Yongdi Liu

Dyeing wastewaters are toxic and carcinogenic to both aquatic life and human beings. Adsorption technology, as a facile and effective method, has been extensively used for removing dyes from aqueous solutions for decades. Numerous researchers have attempted to seek or design alternative materials for dye adsorption. However, using various novel adsorbents to remove dyes has not been extensively reviewed before. In this review, the key advancement on the preparation and modification of novel adsorbents and their adsorption capacities for dyes removal under various conditions have been highlighted and discussed. Specific adsorption mechanisms and functionalization methods, particularly for increasing adsorption capacities are discussed for each adsorbent. This review article mainly includes (1) the categorization, side effects and removal technologies of dyes; (2) the characteristics, advantages and limitations of each sort of adsorbents; (3) the functionalization and modification methods and controlling mechanisms; and (4) discussion on the problems and future perspectives about adsorption technology from adsorbents aspects and practical application aspects.

H2O2 production through photocatalysis has been considered as a sustainable technique. Here, we report ultrathin g-C3N4 nanosheets with hierarchical pores and desirable energy band for high-efficiency photocatalytic H2O2 production. The resultant catalyst showing an ultra-high H2O2 production rate of 1083 μmol g−1 h−1, which is about seven times higher than that of bulk g-C3N4 and represents one of the most active photocatalysts for H2O2 production. DFT calculation and experimental studies revealed that the suitable energy band structure achieved by a phosphorus doping in g-C3N4 leading to the efficient yielding two-electron reduction of O2 to form H2O2. Meanwhile, the particular morphology provided a large accessible surface area, multi-mass transport channels and short charge transfer distance. The synergy effect of desirable energy band and hierarchical porous nanosheets bring the excellent photocatalytic activity. In addition, the simple preparation procedure and the non-metal properties make it have great potential for the practical application.

Due to the rich structures and ingredients, diverse heteroatom doping, regular network hole structure, adjustable unique morphology and pore structure, large specific surface area, Metal-organic frameworks (MOFs) have attracted widespread attention. However, most MOFs have poor stability and are prone to self-decompose in the water phase, which limits their use to remove environmental pollutants. Some recent studies have shown that the porous carbon materials derived from MOFs not only maintain the original structure and morphology, but also get excellent stability in water. Considering these advantages, the carbon materials derived from MOFs represent great potential and high performance as adsorbents and catalysts. So far, MOF-derived carbon-based nanomaterials have been used in the field of environmental adsorption and degradation. In this review, we summarize the classification and morphology control of MOF-derived carbon-based nanomaterials, and then focusing on their application of adsorption, electrocatalytic, photocatalytic and advanced oxidative degradation in the environment field for the first time. Finally, we give our own views on the future development of carbon materials derived from MOFs in the environmental field.

The application of photo-Fenton process is restricted by the acidic pH and additional hydrogen peroxide (H2O2). In order to overcome these drawbacks, a photo-Fenton system of CdS/rGO/Fe2+ which can perform at natural pH with in situ-generated H2O2 has been successfully developed. Highly efficient photo-Fenton degradation of phenol was achieved under the visible light irradiation via the CdS/rGO/Fe2+ system. Experimental results showed that phenol could be degraded completely in 1 h at natural pH. The plentiful in situ generation of H2O2 was further proved to act as an important role in phenol degradation with the addition of Fe2+. The advantages of degradation at natural pH with in situ-generated H2O2 can provide a new prospective to the environmental-friendly Fenton process.

g-C3N4 modified TiO2 composites were prepared through a simple calcination process of anatase and cyanamide. The as-prepared samples were characterized by X-ray diffraction (XRD), diffuse reflectance spectrophotometry (DRS), fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), thermogravimetry differential thermal analysis (TG–DTA) and X-ray photoelectron spectroscopy (XPS), proving a successful modification of TiO2 with g-C3N4. Photodegradation of acid orange 7 (AO7) was used to evaluate the photocatalytic activities of the composites, showing excellent activity of them under both visible and UV light. In addition, base treatment was then introduced to investigate the interaction between g-C3N4 and TiO2. After removing the g-C3N4 modified on TiO2 by base, no nitrogen doping is found in TiO2 lattice, demonstrating the g-C3N4 was surface attached on TiO2 and attributing all improvement of photocatalytic activity of g-C3N4/TiO2 composite to the synergy between the two semiconductors.

In this study, carbon nitride was loaded into the titanium incorporated SBA-15 mesoporous silica (denoted as Ti-SBA15-CN) by a two-step vapor condensation of dicyandiamide. The as-prepared sample was characterized by various spectroscopy techniques. Photocatalytic reduction of Cr (VI) in aqueous solution was investigated using Ti-SBA15-CN under visible-light irradiation. By introducing Ti into the SBA-15 framework structure, the visible light driven photocatalytic activity of the obtained Ti-SBA15-CN was higher than SBA15-CN and the photocatalytic activity exhibited a rise with the increase of Ti contents. It was because the presence of Ti moiety could promote the separation of the photo-generated charge carriers in carbon nitride, leading to the enhancement of the photocatalytic activity. The addition of phenol further enhanced the photocatalytic reduction of Cr (VI). Similarly, the presence of Cr (VI) promoted the degradation of phenol. The synergistic effect between the reduction of Cr (VI) and the degradation of phenol provided salutary method for purification of the complex waste water and environmental restoration.

An active and inexpensive photocatalyst for H2O2 production is desirable for industrial applications. However, obtaining high photocatalytic activity from metal-free catalysts without the use of sacrificial electron donors is difficult. Herein, g-C3N4 (CN) nanotubes functionalized with surface > OH groups that are grafted in situ were successfully synthesized via a novel alkalinization process. The nanotube structures provide a large surface area and improved mass transfer properties. In situ grafted > OH groups can capture photogenerated holes to promote separation of photogenerated charge, enabling the ready availability of electrons and hydrogen ions for H2O2 production. Further, the surface > OH groups help to suppress H2O2 self-decomposition. Consequently, a high rate of 240.36 μmol h−1 g−1 of H2O2 production can be achieved without sacrificial agents, which is the highest H2O2 production in a spontaneous system for metal-free photocatalysts. This work provides a new strategy for an efficient and spontaneous H2O2 production method using a metal-free CN photocatalyst.

A membrane-covered composting system was used to investigate the odor emission and microbial community succession during biogas residue composting. Results showed that in comparison with the control (CK) group, the NH3 and H2S emissions outside the membrane of the membrane-covered (CT) group decreased by 58.64% and 38.13%, respectively. The nitrogen preservation rate of the CT group was increased by 17.27% in comparison with the CK group. Moreover, the ammonium nitrogen and nitrate nitrogen contents of the CT group were 37.68% and 11.77% higher than those of the CK group, respectively. Microbial analysis showed that the average abundance and co-occurrence rate of ammonification bacteria dominated by Pseudomonas and Bacillus in the CT group were lower than those in the CK group, and the abundance of anaerobic sulfate-reducing bacteria (SRB) dominated by Desulfovibrio in the CT group was higher than that in the CK group.

Localized surface plasmon resonances (LSPRs) are usually achieved by some small grains of noble metal (Au, Ag et al.) to enhances the light absorption and charge carrier’s concentration of photocatalysts, but the wide application of noble metals is limited by their high cost. Here, we report the preparation of 0D/2D plasmonic Cu2-xS/g-C3N4 nanosheets (CSCNNs) and the utilization of LSPRs generated from Cu2-xS nanodots instead of noble metals to improve the photocatalytic activity for degradation of typical antibiotic levofloxacin (LVX). One-step hydrothermal method was employed to grow the highly dispersed Cu2-xS nanodots on the g-C3N4 nanosheets. Various characterization techniques verify the strong light absorption capacity and longer carriers’ lifetime for CSCNNs. The analysis of band structure reveals the efficient separation and transmission mechanism of photogenerated electrons and holes. More importantly, LSPRs has been proved to be effective in increasing the light absorption in near infrared (NIR) region and the theoretical finite difference time domain (FDTD) simulations demonstrated that Cu2-xS LSPR-induced electromagnetic field in g-C3N4 nanosheets was far stronger than that of Ag and Au in NIR region. Consequently, efficient photocatalytic degradation of LVX under full solar spectrum (UV–vis-NIR) can be achieved for CSCNNs. This work will lead to a cheap and efficient LSPR photocatalysis system for treatment of antibiotic wastewater or other photocatalytic applications.

Highly efficient removal of tetracycline (TC) has been achieved by cooperative adsorption of carbon and iron in a magnetic Fe/porous carbon hybrid (MagFePC) derived from MIL-101(Fe). The optimum hybrid material MagFePC-700 (obtained from MIL-101(Fe) carbonization at 700 °C had a good adsorption capacity for TC at a wide range of pH, and the highest adsorption capacity was up to 1301.24 mg g−1 at a pH of around 7, which was 6 times higher than that of activated carbon. In addition to TC, it also showed high adsorption capacity (>800 mg g−1) for oxytetracycline, chlortetracycline hydrochloride, and tetracycline hydrochloride. The porous carbon in MagFePC-700 was rich in meso- and micropores, which were conducive to the transport and enrichment of TC molecules. Especially, the Fe nanoparticles in the hybrid were found to contribute greatly to the adsorption, which were both the active site of adsorption and the active site of Fenton reaction. A multi-cycle experiment revealed that the MagFePC material was regenerated well through Fenton reaction, and the regeneration conditions were mild without adjusting the pH. Taken it all together, MagFePC-700 is a green and recyclable adsorbent for the removal of antibiotics from water owing to its high adsorption capacity, easy separation, and good reuse performance.

A novel Z-scheme Ag/AgVO3/carbon-rich g-C3N4 heterojunction with excellent solar-light-driven photocatalytic activity was constructed via a facile hydrothermal-calcining method. The Ag/AgVO3/carbon-rich g-C3N4 composites displayed superior performance for the photocatalytic degradation of sulfamethiadiazole (SFZ) under solar irradiation. The optimal composite with a 10 wt% Ag/AgVO3 content showed the highest photocatalytic activity, its degradation rate constant (k) for SFZ degradation was ∼13 and 30 times than that of carbon-rich g-C3N4 (CCN) and Ag/AgVO3, respectively. Furthermore, •O2– was identified as the most crucial reactive species in the Z-scheme photocatalysis system. The greatly improved photocatalytic activities are derived from the built-in electric field (BIEF) of CCN and efficient Z-scheme charge transfer with Ag nanoparticles as charge transmission-bridge. The possible photocatalytic degradation mechanism and pathway over Ag/AgVO3/carbon-rich g-C3N4 were proposed based on LC-MS analysis and density functional theory (DFT) calculation, and the toxicity of intermediates was evaluated by Quantitative structure–activity relationship (QSAR) based prediction. In summary, this work provides new insight into constructing highly efficient Z-scheme photocatalyst, which is promising for implementation in surface water remediation.

This study describes an integrated granular sludge and fixed-biofilm (iGB) reactor innovatively designed to carry out the anammox/partial-denitrification (A/PD) process for nitrogen removal with mainstream municipal wastewater. The iGB-A/PD reactor consists of anammox granules inoculated in the lower region of reactor and an acclimated fixed-biofilm positioned in the upper region. Compared to the other reported A/PD systems for mainstream wastewater treatment, this iGB-A/PD reactor is notable due to its higher quality effluent with a total inorganic nitrogen (TIN) of ∼3 mg•L-1 and operation at a high nitrogen removal rate (NRR) of 0.8 ± 0.1 kg-N•m-3•d-1. Reads-based metatranscriptomic analysis found that the expression values of hzsA and hdh, key genes associated with anammox, were much higher than other functional genes on nitrogen conversion, confirming the major roles of the anammox bacteria in nitrogen bio-removal. In both regions of the reactor, the nitrate reduction genes (napA/narG) had expression values of 56-99 RPM, which were similar to that of the nitrite reduction genes (nirS/nirK). The expression reads from genes for dissimilatory nitrate reduction to ammonium (DNRA), nrfA and nirB, were unexpectedly high, and were over the half of the levels of reads from genes required for nitrate reduction. Kinetic assays confirmed that the granules had an anammox activity of 16.2 g-NH4+-N•kg-1-VSS•d-1 and a nitrate reduction activity of 4.1 g-N•kg-1-VSS•d-1. While these values were changed to be 4.9 g- NH4+-N•kg-1-VSS•d-1and 4.3 g-N•kg-1-VSS•d-1 respectively in the fixed-biofilm. Mass flux determination found that PD and DNRA was responsible for ∼50% and ∼25% of nitrate reduction, respectively, in the whole reactor, consistent with high effluent quality and treatment efficiency via a nitrite loop. Metagenomic binning analysis revealed that new and unidentified anammox species, affiliated with Candidatus Brocadia, were the dominant anammox organisms. Myxococcota and Planctomycetota were the principal organisms associated with the PD and DNRA processes, respectively.

Using MOFs MIL-101-NH2 (Fe) mixed with lignin uniformly as precursors, Carbon-Fe3C/lignin composites were prepared by carbonization for efficient adsorption removal of tetracycline (TC) from wastewater. The doping of lignin in MOFs MIL-101-NH2 (Fe) increased the BET surface area (160.9 m2/g) of the obtained porous carbon materials, made Fe nanoparticles more dispersed on carbon matrix, and brought more defects and oxygen-containing groups as active adsorption sites. As a result, the materials had excellent adsorption performance for TC in a wide pH range, and the maximum adsorption capacity reached 760.36 mg/g when pH was 4.19, which was 2 times higher than that of Carbon-MIL-101-NH2. The mechanism investigation revealed that the adsorption mainly included chemical adsorption (chemical bonds, ion exchange, π-π interaction and electrostatic interaction) and physical adsorption. It was found that the materials also had a good adsorption effect on tetracycline hydrochloride, oxytetracycline and chlortetracycline (>350 mg/g) and heavy metal Cr(VI) (164 mg/g). Significantly, adsorbent had excellent cycle stability and can be easily recovered from water through magnetic separation, ensuring its great potential for practical wastewater treatment.

Traditional defect engineering and doping strategies are considered effective means for improving H2 evolution, but the uncontrollability of the modification process does not always lead to efficient activity. A defect-induced heteroatom refilling strategy is used here to synthesize heteroatoms introduced carbon nitride by precisely controlling the "introduction" sites on efficient N1 sites. Density functional theory calculations show that the refilling of B, P, and S sites have stronger H2 O adsorption and dissociation capacity than traditional doping, which makes it an optimal H2 production path. The large internal electric field strength of heteroatom-refilled catalysts leads to fast electron transfer and the hydrogen production of the best sample is up to 20.9 mmol g-1 h-1 . This work provides a reliable and clear insight into controlled defect engineering of photocatalysts and a universal modification strategy for typical heteroatom and co-catalyst systems for H2 production.

Additives could improve composting performance and reduce gaseous emission, but few studies have explored the synergistic of additives on H2S emission and compost maturity. This research aims to make an investigation about the effects of chemical additives and mature compost on H2S emission and compost maturity of kitchen waste composting. The results showed that additives increased the germination index value and H2S emission reduction over 15 days and the treatment with both chemical additives and mature compost achieved highest germination index value and H2S emission reduction (85%). Except for the treatment with only chemical additives, the total sulfur content increased during the kitchen waste composting. The proportion of effective sulfur was higher with the addition of chemical additives, compared with other groups. The relative abundance of H2S-formation bacterial (Desulfovibrio) was reduced and the relative abundance of bacterial (Pseudomonas and Paracoccus), which could convert sulfur-containing substances and H2S to sulfate was improved with additives. In the composting process with both chemical additives and mature compost, the relative abundance of Desulfovibrio was lowest, while the relative abundance of Pseudomonas and Paracoccus was highest. Taken together, the chemical additives and mature compost achieved H2S emission reduction by regulating the dynamics of microbial community.

Cofactors, including reduced nicotinamide adenine dinucleotide (NADH), are involved in approximately 80 % of oxidoreductase-catalyzed reactions. However, NADH has not been widely used in the industrial production processes due to cost factors. In this work, we have designed a kind of metal-free core-shell photocatalyst with resorcinol-formaldehyde resin spheres as the core and polyaniline as the shell (RF@PANI) for the highly efficient and selective photocatalytic regeneration of 1,4-NADH (only 1,4-NADH has enzyme activity). It was demonstrated that the introduction of the carbonyl group and the sum of electronic effects made the C4 site of NAD+ a more electrophilic hydride transfer site rather than C6 and C2 in the RF@PANI system, leading to the high selectivity of NAD+ to 1,4-NADH. The discovery of this mechanism will guide the design of more efficient and highly selective catalysts to break through the cost limitations for the large-scale applications of NADH.

Structural shifts associated with functional dynamics in a bacterial community may provide clues for identifying the most valuable members in an ecosystem. A laboratory-scale denitrifying reactor was adapted from use of non-efficient seeding sludge and was utilized to degrade quinoline and remove the chemical oxygen demand. Stable removal efficiencies were achieved after an adaptation period of six weeks. Both denaturing gradient gel electrophoresis profiling of the 16S rRNA gene V3 region and comparison of the 16S rRNA gene sequence clone libraries (LIBSHUFF analysis) demonstrated that microbial communities in the denitrifying reactor and seeding sludge were significantly distinct. The percentage of the clones affiliated with the genera Thauera and Azoarcus was 74% in the denitrifying reactor and 4% in the seeding sludge. Real-time quantitative PCR also indicated that species of the genera Thauera and Azoarcus increased in abundance by about one order of magnitude during the period of adaptation. The greater abundance of Thauera and Azoarcus in association with higher efficiency after adaptation suggested that these phylotypes might play an important role for quinoline and chemical oxygen demand removal under denitrifying conditions.

Dissolved organic matter (DOM) in the biotreated effluent of a municipal wastewater treatment plant was separated by XAD-8 and XAD-4 resins into four fractions: hydrophobic acids, non-acid hydrophobics, transphilics and hydrophilics. Ozonation with and without ultraviolet (UV) enhancement removed most UV-absorbing substances in the first 30 min achieving 78% and 63% reduction in UV254, respectively; the UV enhancement resulted in a greater reduction in dissolved organic carbon (DOC) (90% vs. 36%). Ozone reacted sequentially with aromatic hydrophobics, transphilics, and then hydrophilics; however, under UV, it reacted with all four organic fractions simultaneously. Low-MW hydrophilics were the most abundant fraction in the ozone-treated effluent.

Well dispersed TiO2 nanocrystals with (001) facets were successfully grown in situ on g-C3N4 through a facial solvothermal method. The resultant TiO2/g-C3N4 composites exhibit remarkably higher efficiency for photocatalytic degradation of phenol as compared to pure catalysts (g-C3N4 or TiO2) or mechanically mixed TiO2/g-C3N4. The optimal composite with 11.2 wt% TiO2 showed the highest degradation rate constant, which is 2.8 times that of pure g-C3N4, 2.2 times that of pure TiO2, and 1.4 times that of mechanically mixed TiO2/g-C3N4. The enhanced photocatalytic activity is mainly attributed to the effective charge separation derived from two aspects: (1) well matched energy levels between TiO2 and g-C3N4 and (2) a uniform and close contact between TiO2 and g-C3N4 that resulted from the in situ growth of highly dispersed TiO2 nanocrystals. The TiO2/g-C3N4 hybrid material prepared in this study is expected to provide a good foundation for the further design and synthesis of advanced TiO2/g-C3N4-based functional materials, and the in situ growth method developed is hopeful to provide a new strategy for the synthesis of other semiconductor-modified g-C3N4 materials.

A novel heterojunction photocatalyst with well-dispersed TiO2 nanoparticles on Co-Doped g-C3N4 has been successfully fabricated by an in situ generation solvothermal method. The photocatalytic performance of the as-prepared TiO2/Co-g-C3N4 catalyst was evaluated by the degradation of phenol in the presence of Cr6 + under simulated sunlight irradiation. The catalyst exhibited markedly enhanced photocatalytic activity for degradation of phenol but obviously decreased photocatalytic activity for reduction of Cr6 + compared with common TiO2/g-C3N4 catalyst. The mechanism for this photocatalytic performance was proposed.

In the field of green chemistry, producing hydrogen peroxide (H2O2) via photocatalysis could be a promising method for obtaining chemical feedstock during industrial and environmental processes. Herein, we simultaneously introduced inverse opal (IO) structure and carbon vacancies (CVs) into carbon nitride to improve H2O2 production by photocatalysis. Experimental results reveal that, after visible light irradiation for 2 h, IO carbon nitride (IO CN-Cv) shows a H2O2 generation value of 325.74 μM over 1.69, 2.13, and 1.84 times more than the H2O2 generation of bulk CN-Cvs (bulk carbon nitride with Cvs), bulk CN (bulk carbon nitride without Cvs), and nanosheet CN (carbon nitride nanosheet), respectively. On the one hand, the typical IO structure improves the efficiency of visible light absorption and simultaneously provides more surface area for the adsorption of molecular oxygen. Meanwhile, the introduction of Cvs improves the separation ability of carriers. This study offers a new idea for enhanced production of H2O2 using visible light with metal-free materials in the era of energy shortage.

The microbial safety of swimming pool waters (SPWs) becomes increasingly important with the popularity of swimming activities. Disinfection aiming at killing microbes in SPWs produces disinfection by-products (DBPs), which has attracted considerable public attentions due to their high frequency of occurrence, considerable concentrations and potent toxicity. We reviewed the latest research progress within the last four decades on the regulation, formation, exposure, and treatment of DBPs in the context of SPWs. This paper specifically discussed DBP regulations in different regions, formation mechanisms related with disinfectants, precursors and other various conditions, human exposure assessment reflected by biomarkers or epidemiological evidence, and the control and treatment of DBPs. Compared to drinking water with natural organic matter as the main organic precursor of DBPs, the additional human inputs (i.e., body fluids and personal care products) to SPWs make the water matrix more complicated and lead to the formation of more types and greater concentrations of DBPs. Dermal absorption and inhalation are two main exposure pathways for trihalomethanes while ingestion for haloacetic acids, reflected by DBP occurrence in human matrices including exhaled air, urine, blood, and plasma. Studies show that membrane filtration, advanced oxidation processes, biodegradation, thermal degradation, chemical reduction, and some hybrid processes are the potential DBP treatment technologies. The removal efficiency, possible mechanisms and future challenges of these DBP treatment methods are summarized in this review, which may facilitate their full-scale applications and provide potential directions for further research extension.

TiO2 inverse opal photonic crystal (TiO2 IO PCs) that possesses the advantages of titanium dioxide including non-toxicity, high refractive index (>2.5), good biocompatibility etc. and the optical characteristics of photonic crystals containing the band gap, photonic localization, slow light effect, super prism effect and negative refraction effect has attracted tremendous interest. Its synthetic methods are usually chemical vapor deposition, atomic layer deposition, electrochemical deposition and sol-gel method. To meet the needs of the applications in chemical sensors, solar cells, photocatalysis, high efficient microwave wire, photonic crystal fiber etc., lots of research focused on the modifications of TiO2 IO PCs by means of noble metal deposition, non-metal elements or metal ion doping, quantum dot sensitization and semiconductor composite. This paper aims to review the up-to-date synthesis, modification, and applications of TiO2 IO PCs and forecast its future development direction.

The purpose of this study was to investigate the enhanced biogas production and biodegradation of phenanthrene in sludge treated anaerobic digestion (AD) reactors fitted with a bioelectrode system (AD-MEC reactors). Different cathodes were considered for installation in the AD-MEC reactor. The result showed that the maximum methane yield (113.45 L/kg TS) and the highest phenanthrene degradation rate (52.3%) were obtained in a reactor with a carbon paper (CP) cathode; this performance was 30.5% and 83.5% greater, respectively, than that in the AD control reactor. Clostridia spp., bacteria that degrade pollutants, were specifically adsorbed onto the electrodes, and Methanosaeta spp. and Geobacter spp. were enriched on the anode. These results implied that a potential direct electron transfer occurred between Methanosaeta and Geobacter. Two hydrogenotrophic methanogens (Methanospirillum spp. and Methanobacterium spp.) were enriched on the surface of the cathode, which enhanced interspecies H2 transfer in the AD-MEC reactors.

At present, the assessment of photooxidation system mainly focuses on the photodegradation efficiency of target pollutant, lacking of the toxicity assessment in the photocatalysis process. Here, photodecomposition of bisphenol A (BPA) was used to investigate the performance of several cyclodextrin modified photocatalysts. Moreover, the comprehensive toxicity changes of BPA under different photocatalytic oxidation conditions were conducted. The β-cyclodextrin (β-CD) modified photocatalyst, including titanium dioxide (CM-β-CD-TiO2), carbon nitride (CM-β-CD-C3N4) and cadmium sulfide (SH-β-CD-AM/CdS) exhibit high degradation rate and mineralization efficiency of BPA. The highest total organic carbon (TOC) removal of BPA observed in the oxidation system of SH-β-CD-AM/CdS nanoreactor (73.4%). The main oxidation intermediates in these systems were detected, and the comprehension toxicity of BPA and its oxidation intermediates in different system were compared by toxicity estimation software tool (T.E.S.T.) based on quantitative structure-activity relationship (QSAR) prediction. The results show that β-CD can facilitate the photodecomposition of the target contaminant. However, many oxidation intermediates with high comprehensive toxicity, even in the oxidation system with high BPA removal, can still be detected. Therefore, not only decomposition of target contaminant but also the comprehensive toxicity of oxidation intermediates should be regarded as index to evaluate a photocatalysis technology.

In this study, Ni/Fe nanoparticles supported by biochar to stimulate the reduction of 1,1,1-trichloroethane (1,1,1-TCA) in groundwater remediation was investigated. In order to enhance the reactivity of ZVI (zero valent iron) nanoparticles, surface modification of ZVI was performed using nickel and biochar. The removal efficiency of 1,1,1-TCA increased from 42.3% to 99.3% as the biochar-to-Ni/Fe mass ratio increased from 0 to 1.0. However a higher biochar-to-Ni/Fe ratio showed little difference in the 1,1,1-TCA degradation efficiency. In the presence of Ni, atomic hydrogen generated by ZVI corrosion could be absorbed in the metal additive's lattice and then produce a hydride-like species (H) that represented the primary redox-active entity. The effects of various factors were evaluated, including pH, humic acid (HA) and inorganic matters (Cl−, CO32–, HCO3−, NO3− and SO42–). The degradation of 1,1,1-TCA was greatly affected by pH. The presence of Cl−, CO32–, HCO3− and SO42− had negligible effects, but NO3− and HA showed a significant inhibitory effects on 1,1,1-TCA degradation. In conclusion, biochar supported Ni/Fe nanoparticles could be highly effective for 1,1,1-TCA degradation.

In this study, a highly efficient heterogeneous photo‐Fenton system (Fe 2 O 3 /g‐C 3 N 4 /H 2 O 2 /visible light) has been developed. The heterogeneous catalyst Fe 2 O 3 /g‐C 3 N 4 in this system was successfully prepared by growing Fe 2 O 3 nanoparticles on the surface of g‐C 3 N 4 . The Fe 2 O 3 nanoparticles could achieve high dispersion on the surface of g‐C 3 N 4 and form a heterojunction with g‐C 3 N 4 to improve the charge separation. In addition, the combination of the Fenton's reagent Fe 2 O 3 /H 2 O 2 and the photocatalyst g‐C 3 N 4 greatly enhances the rate of the Fenton's reaction with the assistance of the photocatalytic process. The results showed that the Fe 2 O 3 /g‐C 3 N 4 catalyst had a superior catalytic activity as compared with the single component of Fe 2 O 3 or g‐C 3 N 4 and the mechanical mixture of Fe 2 O 3 and g‐C 3 N 4 . The catalyst prepared with 3 mL of FeCl 3 aqueous solution shows the best photo‐Fenton photocatalytic efficiency with a reaction rate constant of 0.02461 mg L –1 min –1 , which is about 45.4, 8.4 and 7.2 times larger than that of pure Fe 2 O 3 (0.0005418 mg L –1 min –1 ), pure g‐C 3 N 4 (0.00294 mg L –1 min –1 ) and the mechanically mixed Fe 2 O 3 /g‐C 3 N 4 (0.0034 mg L –1 min –1 ), respectively. A possible mechanism for the visible‐light‐irradiated photo‐Fenton photocatalysis is proposed, and the Fe 2 O 3 /g‐C 3 N 4 catalyst exhibited stable performance without obvious loss of catalytic activity after four successive runs, showing a good application prospect for the photo‐oxidative degradation of organic contaminants in wastewater.

A composite catalyst combining CoP with g‐C 3 N 4 was explored for the photocatalytic production of H 2 O 2 under visible‐light irradiation. The composite catalyst was fabricated by growth of CoP nanoparticles on the surface of g‐C 3 N 4 . The CoP nanoparticles were well dispersed on the surface of g‐C 3 N 4 and could interact with g‐C 3 N 4 to improve charge separation and electron transfer. The composite catalyst showed superior catalytic activity compared with pure CoP or g‐C 3 N 4 under visible‐light irradiation. The optimal catalyst with 1.76 wt.‐% CoP loading exhibited the best photocatalytic efficiency with an H 2 O 2 production of 140 µ m in 2 h, which is about 4.6 and 23.3 times those of pure g‐C 3 N 4 and pure CoP, respectively. A possible mechanism for the visible‐light‐driven photocatalytic production of H 2 O 2 is proposed. The composite catalyst exhibited stable performance without obvious loss of catalytic activity after seven successive runs, and thus has good application prospects in sustainable H 2 O 2 production.

In this work, the Fe2O3-SiO2 composite photo-Fenton catalyst was designed and synthesized as a photonic crystal with a hierarchical macro-mesoporous structure, which possesses a slow-light-effect region that overlaps with the absorption spectrum of methyl orange (MO). The prepared material exhibits remarkably high and stable photo-Fenton catalytic performance for the degradation of MO using only a low concentration of H2O2 under visible light irradiation. The catalytic activity of the as-prepared material is better than that of the corresponding macroporous or mesoporous Fe2O3-SiO2 composites as well as commercial Fe2O3 or the homogenous photo-Fenton system of FeCl3 · 6H2O. The efficient use of H2O2 and the high catalytic activity are attributed to (i) the excellent adsorption of MO by the hierarchical macro-mesoporous structure and (ii) enhanced light harvesting from coupling the absorption spectrum of MO with the slow-light-effect region of the photonic crystal. This hierarchical macro-mesoporous Fe2O3-SiO2 photonic crystal is expected to be a promising cost-effective photo-Fenton catalyst for degradation of a variety of dyes by deliberately tuning its slow-light-effect region, and opens up new perspectives for the development of highly efficient photo-Fenton catalysts for environmental remediation technology.

The salt-tolerance aerobic granular sludge (SAGS) dominated by moderately halophilic bacteria was successfully cultured in a 9% (w/v) salty, lab-scale sequence batch reactor (SBR) system. Influence of high salinity (0-9% w/v NaCl) on the formation, performance and microbial succession of the SAGS were explored. Crystal nucleus hypothesis, selection pressure hypothesis and compressed double electric layers hypothesis were used to discuss the formation mechanism of SAGS. Notably, salinity could be seen as a kind of selection pressure contributed to the formation of SAGS, while salinity also declined the performance of SAGS system. High throughput 16S rRNA gene analysis showed that the salinity had great influence on the species succession and community structure of SAGS. Moreover, Salinicola and Halomonas were dominant at 9% salt concentration, therefore moderate halophiles were identified as functional groups for the tolerance of hypersaline stress.

The photocatalytic activity of g-C₃N₄ was restricted by the fast charge recombination of photo-generated electrons and holes.

Hierarchical macro-mesoporous g-C₃N₄ with an inverse opal structure and vacancies was prepared and exhibited excellent performance for photocatalytic H₂ production and antibiotic degradation.

Tris(1,3-dichloro-2-propyl)phosphate (TDCPP) is a halogen-containing organophosphorus chemical that is widely employed in various consumer products with a high production volume. As an additive flame retardant (FR), TDCPP tends to be released into the environment through multiple routes. It is ubiquitous in environmental media, biotic matrixes, and humans, and thus is deemed to be an emerging environmental contaminant. To date, significant levels of TDCPP and its primary diester metabolite, bis(1,3-dichloro-2-propyl)phosphate, have been detected in human samples of seminal plasma, breast milk, blood plasma, placenta, and urine, thereby causing wide concern about the potential human health effects resulting from exposure to this chemical. Despite the progress in research on TDCPP over the past few years, we are still far from fully understanding the environmental behavior and health risks of this emerging contaminant. Thus, this paper critically reviews the environmental occurrence, exposure, and risks posed by TDCPP to organisms and human health among the literature published in the last decade. It has been demonstrated that TDCPP induces acute-, nerve-, developmental-, reproductive-, hepatic-, nephron-, and endocrine-disrupting toxicity in animals, which has caused increasing concern worldwide. Simultaneously, TDCPP induces cytotoxicity by increasing the formation of reactive oxygen species and inducing endoplasmic reticulum stress in multiple human cell lines in vitro, and also causes endocrine-disrupting effects, including reproductive dysfunction and adverse pregnancy outcomes, according to human epidemiology studies. This review not only provides a better understanding of the behavior of this emerging contaminant in the environment, but also enhances the comprehension of the health risks posed by TDCPP exposure to ecosystems and humans.

Photocatalytic H2O2 production is an environmentally friendly and sustainable production technique. Here, we fabricate the Ti3C2 quantum dot-modified defective inverse opal g-C3N4 (TC/CN) via a facile electrostatic self-assembly method. The resultant catalysts greatly facilitate the photocatalytic H2O2 production. The optimum H2O2 yield on TC/CN-20 reaches 560.7 μmol L–1 h–1, which is 9.3 times higher than that of bulk CN under visible light irradiation. This enhancement is attributed to the direction-induced bonding between carbon vacancies in g-C3N4 and TCQDs. The formation of a Schottky junction in the interface further realizes spatial separation of electron and holes, effectively avoiding the recombination of the charge carriers at defect sites. Therefore, this work not only constructs a high-performance photocatalyst for H2O2 production with outstanding yield and long-term recyclability but also develops a direction-induced bonding synthetic method and explores the functionary mechanism of defect sites in the Schottky junction for photocatalytic H2O2 production.

Nitrate production during anammox can decrease total nitrogen removal efficiency, which will negatively impact its usefulness for the removal of nitrogen from waste streams. However, neither the performance characteristics nor physiological shifts associated with nitrate accumulation in anammox reactors under different nitrogen loading rates (NLRs) is well understood. Consequently, these parameters were studied in a lower NLR anammox reactor, termed R1, producing higher than expected levels of nitrate and compared with a higher NLR reactor, termed R2, showing no excess nitrate production. While both reactors showed high NH4+-N removal efficiencies (>90%), the total nitrogen removal efficiency (<60%) was much lower in R1 due to higher nitrate production. Metagenomic analysis found that the number of reads derived from anammox bacteria were significantly higher in R2. Another notable trend in reads occurrence was the relatively higher levels of reads from genes predicted to be nitrite oxidoreductases (nxr) in R1. Binning yielded 27 high quality draft genomes from the two reactors. Analysis of bin occurrence found that R1 showing both a decrease in anammox bacteria and an unexpected increase in nxr. In-situ assays confirmed that R1 had higher rates of nitrite oxidation to nitrate and suggested that it was not solely due to obligate NOB, but other nxr-containing bacteria are important contributors as well. Our results demonstrate that nitrate accumulation can be a serious operational concern for the application of anammox technology to low-strength wastewater treatment and provide insight into the community changes leading to this outcome.

The efficient degradation of fluoroquinolone antibiotics and the reduction of their antimicrobial activity were achieved in different water matrices through the photocatalysis of inverse opal potassium-doped carbon nitride (IO K-CN). The IO K-CN photocatalyst with optimum doping ratio of potassium performed much better than bulk carbon nitride and pure inverse opal carbon nitride for removing fluoroquinolone antibiotics, such as levofloxacin (LVX) and norfloxacin (NOR). The remarkably narrowed band gap resulting from potassium doping and the unique properties of the inverse opal construction jointly contributed to enhancing the activity of the photocatalyst. A possible mechanism and degradation pathway for LVX was proposed on the basis of a series of characterizations including electron spin resonance (ESR) experiments, and liquid chromatography-mass spectrometry (LC-MS) analysis. Meanwhile, the byproducts during the LVX photocatalytic degradation were shown to have much lower sterilization effect, implying that the toxicity and the potential risk of LVX were excellently reduced. The potential application for the treatment of antibiotic-containing wastewater was indicated by the excellent treatment efficiency and favorable durability of this photocatalyst.

This study investigated methane production and ARGs reduction during thermophilic AD of swine manure with the addition of different Cu salts (cupric sulfate, cupric glycinate, and the 1:1 mixture of these two salts). Results showed methane production was increased by 28.78% through adding mixed Cu salts. The mixed Cu group effectively reduced total ARGs abundance by 26.94%, suggesting mixed Cu salts did not promote the potential ARGs risk. The positive effects of mixed Cu salts on AD performance and ARGs removal might be ascribed to the low bioavailability. Microbial community analysis indicated the highest abundances of Clostridia_MBA03 and Methanobacterium in the mixed Cu group might cause the increased methane production. Spearman’s rank correlation analysis elucidated the succession in microbial community induced by environmental factors was the main driver for shaping ARGs profiles. Thus, mixed Cu salts could be an alternative to replace the inorganic Cu salt in animal feed additives.

A novel carbon-rich g-C3N4 nanosheets with large surface area was prepared by facile thermal polymerization method using urea and 1,3,5-cyclohexanetriol. Plenty of carbon-rich functional groups were introduced into the surface layers of g-C3N4, which constructed the built-in electric field (BIEF) and resulted in improved charge separation; therefore, the carbon-rich g-C3N4 displayed superior photocatalytic activity for amoxicillin degradation under solar light. The contaminant degradation mechanism was proposed based on radical quenching experiments, intermediates analysis and density functional theory (DFT) calculation. Moreover, the reusing experiments showed the high stability of the material, and the amoxicillin degradation under various water matrix parameters indicated its high applicability on pollutants treatment, all of which demonstrated its high engineering application potentials.

A highly solar active nanocomposite with sheet-like WO3 skeleton and evenly loaded TiO2 and carbon quantum dots (CQDs) was synthesized by facile hydrothermal-calcining process, which showed 3.1- and 46.6- times activity on antibiotic (cephalexin) degradation than TiO2 and WO3, respectively. The construction of TiO2/WO3 heterojunction narrowed the band gap and facilitated the electrons-holes separation. The π conjugated CQDs was found to further improve the charge separation and extend the visible light response by photosensitization. However, the promoted charge separation predominantly contributed to the improved photocatalytic activity. The contributions of detected reactive species follows the order of: O2–>1O2>OH>h+. The cephalexin degradation mechanism and pathway were proposed based on DFT (density functional theory) calculation and experimental analysis. The photocatalytic mineralization efficiency can reach 92.4% in 4 h, indicating the efficient reduction of ecotoxicity of cephalexin and its intermediates. This new composite proved to have great potentials for emerging contaminants degradation in water.

This study investigated the changes of phosphorus (P) fractions, bacterial community and their response to available P or carbon (C):P during composting with different rock phosphate (RP) addition levels. Results showed that adding RP at 10% or 15% promoted the rise of temperature, maturity and Olsen P accumulation in composting, which had a higher amount of RP solubilization than other groups. Available P changed bacterial composition and decreased diversity in composts. RP solubilization efficiency was negatively correlated to C:P ratio and the highest (22.7%) when 10% RP was added, in which bacterial community changed from "function redundancy" to "intensive P-solubilization". Low C:P ratio (〈300) increased the RP solubilization ratio especially within 135–160. Therefore, this study proposed that adding P-rich substrates to decrease C:P ratio could regulate P-solubilizers' activity for increasing RP solubilization efficiency during composting.

Photo-Fenton process is an advanced oxidation technology, which is used to eliminate organic pollutants in environmental pollution. In this paper, g-C3N4 quantum dots incorporated hierarchical macro-mesoporous CuO-SiO2 (MM SC-QDs) composite was successfully fabricated by a dual-template method combined with polystyrene sphere (PS) crystal and copolymer F127. With the presence of H2O2, MM SC-QDs exhibited excellent degradation performance against the antibiotic pollutant norfloxacin (NOR) under visible-light assisted heterogeneous Fenton process at neutral condition, which was 27 times higher than that of the Bulk CuO-SiO2. Interconnected macropores, together with abundant mesopores effectively expand specific surface area and improve mass transfer. In addition, the g-C3N4 QDs served as the separation center for photogenerated charges, promoting the separation and migration of the charge carriers. Wherein, the long-lived photogenerated electrons were effectively separated and transferred to the surface of CuO-SiO2, which accelerated the reduction rate of Cu2+ to Cu+, enhancing the photo-Fenton-like catalytic activity. This stable, efficient, and environmentally friendly Cu-based heterogeneous photo-Fenton-like catalyst is expected to become an effective implementation in organic pollution removal. Meanwhile, this paper proves that Cu-based materials can activate H2O2 to generate singlet oxygen (1O2) for the degradation of organic pollutants. The transformation mechanism of 1O2 was clarified, which is helpful to better understand the Fenton-like reaction process of Cu-based materials.

Window composting with inoculation or frequent turning is a superior way to improve traditional composting efficiency. However, the relationship between the innocent treatment in composting with inoculation or turning and microbial dynamics is unclear. Here, the impact of inoculation and turning for full scale composting on core bacterial community and their co-occurrence network as well as harmless level were compared by network analysis. Results showed that composts with both inoculation and turning had 46% increase of total organic carbon degradation compared to traditional composting and decreased the abundance of potential pathogens. The relative abundance of thermophilic bacteria and Galbibacter, Methylocaldum, Steroidobacter, etc. increased during composting with turning and inoculation. Luteimonas, Sphaerobacter, Turicibacter and Flavobacterium as core bacteria had significant difference between control and composting with enhanced innocent treatment efficiency. Network analysis suggested that turning increased the number of indigenous core bacteria and inoculation enhanced the interaction among key bacterial network.

Composting is widely used as an easily operated and economical method to manage organic wastes. However, the long residence time of composting impedes the recycling nutrients from large amounts of organic wastes produced every day. In this study, the intelligent biodrying + continuous dynamic trough (IB + CDT) was created and used in China’s first urban and rural organic waste treatment and utilization demonstration center in Suzhou city. Results showed that IB + CDT composting had higher temperature, more reduction of moisture than windrow composting, enhancing 40% of composting efficiency. Primary fermentation of the IB + CDT composting in the indoor conditions could achieve the harmless treatment (GI > 80%) of compost within 12 days. The IB + CDT composting product enhanced 17% soil organic matter and 11% available nitrogen. The IB + CDT composting mode could earn 57.6 USD/ton by recycling organic waste and producing organic fertilizer, leading to a sustainable and profitable mode.

Advanced oxidation processes (AOPs) such as Fenton and Fenton-like process for pollutant removal have been widely reported. However, most papers choose one of the popular oxidants (H2O2, peroxymonosulfate (PMS) or peroxydisulfate (PDS)) as the oxidant via AOPs for pollutant degradation. The purpose of this work is to compare the degradation rates of the Fe2+/PMS, Fe2+/H2O2 and Fe2+/PDS processes. Furthermore, to solve the problem of slow regeneration of Fe2+, the visible light irradiation and inverse opal WO3 cocatalyst were added to the Fenton/Fenton-like process. The IO WO3 co-catalytic visible light assisted Fe2+/PMS, Fe2+/H2O2 and Fe2+/PDS processes greatly improved the degradation efficiency of norfloxacin (NOR), reaching about 30 times, 9 times and 12 times that of the homogeneous Fenton/Fenton-like process, respectively. On average, the TOC removal rates of PMS-based, H2O2-based and PMS-based processes for the five pollutants were 71.6%, 54.0%, and 59.6% within 60 min, and the corresponding co-catalyst treatment efficiencies were 0.215 mmol/g/h, 0.162 mmol/g/h, and 0.179 mmol/g/h, respectively. 1O2 and •O2- have been proven to play a vital role in the degradation of NOR via all the three IO WO3 co-catalytic photo-Fenton-like processes. In addition, the effects of different reaction parameters on the activity of degrading norfloxacin were explored. The IO WO3 co-catalytic visible light assisted Fe2+/PMS, Fe2+/H2O2 and Fe2+/PDS processes for removal of different persistent organic pollutants and norfloxacin in different actual wastewater have also been studied. Nonetheless, this study proves that IO WO3 co-catalytic visible light assisted Fe2+/PMS, Fe2+/H2O2 and Fe2+/PDS processes could effectively remove antibiotics from wastewater.

Antibiotic resistance genes (ARGs) and their host antibiotic-resistant bacteria (ARB) are widely detected in the environment and pose a threat to human health. Traditional disinfection in water treatment plants cannot effectively remove ARGs and ARB. This study explored the potential of a heterogeneous photo-Fenton-like process utilizing a hierarchical macro-mesoporous Co3O4-SiO2 (MM CS) catalyst for activation of peroxymonosulfate (PMS) to inactivate ARB and degrade the intracellular ARGs. A typical gram-negative antibiotic-resistant bacteria called Pseudomonas sp. HLS-6 was used as a model ARB. A completed inactivation of ARB at ∼107 CFU/mL was achieved in 30 s, and an efficient removal rate of more than 4.0 log for specific ARGs (sul1 and intI1) was achieved within 60 min by the MM CS-based heterogeneous photo-Fenton-like process under visible light and neutral pH conditions. Mechanism investigation revealed that •O2- and 1O2 were the vital reactive species for ARB inactivation and ARG degradation. The formation and transformation of the active species were proposed. Furthermore, the hierarchical macro-mesoporous structure of MM CS provided excellent optical and photoelectrochemical properties that promoted the cycle of Co3+/Co2+ and the effective utilization of PMS. This process was validated to be effective in various water matrices, including deionized water, underground water, source water, and secondary effluent wastewater. Collectively, this work demonstrated that the MM CS-based heterogeneous photo-Fenton-like process is a promising technology for controlling the spread of antibiotic resistance in aquatic environments.

This study is aimed at adding different types of mature compost and sulfur powder, as additives into food waste composting to investigate the effect on nitrogen loss and compost maturity. The composting experiment used the in-vessel composting method and was conducted continuously for 15 days. High-throughput sequencing was used to analyze the bacterial community during composting. Results showed that the secondary fermentation mature compost mixed with sulfur powder group had the most reduction of ammonia emission (56%) and the primary fermentation mature compost amendments were the most effective for nitrous oxide emission reduction (37%). The temperature, pH, and nitrogen forms of transformation of the pile significantly affect the nitrogen loss during composting. Firmicutes helped to promote the rapid warming of the pile, and Actinobacteria and Proteobacteria played an important role in decomposition of organic matter. Thermobifida and Ureibacillus had a main contribution to the rapid degradation of organic matter in the process of composting. The relative abundance of nitrogen-fixing bacteria was higher, and the relative abundance of predominantly ammonifying and denitrifying bacteria was lower than the control group, with the addition of different additives.

This study investigated the effects of different carbon-based additives including biochar, woody peat, and glucose on humic acid, fulvic acid, and phosphorus fractions in chicken manure composting and its potential for phosphorus mobilization in soil. The results showed that the addition of glucose effectively increased the total humic substance content (90.2 mg/g) of composts, and the fulvic acid content was significantly higher than other groups (P < 0.05). The addition of biochar could effectively improve the content of available phosphorus by 59.9% in composting. The addition of carbon-based materials to the composting was beneficial for the production of more stable inorganic phosphorus in the phosphorus fraction. The highest proportion of soluble inorganic phosphorus components of sodium hydroxide was found in group with woody peat addition (8.7%) and the highest proportion of soluble inorganic phosphorus components of hydrochloric acid was found in group with glucose addition (35.2%). The compost products with the addition of biochar (humic acid decreased by 17.9%) and woody peat (fulvic acid decreased by 72.6%) significantly increased soil humic acid mineralization. The compost products with the addition of biochar was suitable as active phosphate fertilizer, while the compost products with the addition of glucose was suitable as slow-release phosphate fertilizer.

A Fe-doped CeO2 was fabricated for catalytic ozonation of Amoxicillin (AMX), and the catalytic mechanisms were explored in this study. Under optimal conditions (the initial solution pH of 7.0, FC-0.3 dosage of 0.5 g/L, O3 dosage of 4 mg/min), the AMX and TOC removal by the optimal material (FC-0.3, at Fe/Ce atomic ratio of 0.3) reached 98.1 % at 24 min and 55.2 % at 36 min, respectively. Improved the AMX mineralization efficiency by 3.7 times. The experiments and theoretical calculation reveal the mechanisms of promoted catalytic ozonation by FC-0.3: 1) Highly abundant surface-active sites (i.e., –OH) enabled the adsorption of H2O and O3, which was favorable to the generation of reactive oxygen species (ROS) and improved the reaction probability for ROS and contaminants. 2) The synergistic effect between Ce4+/Ce3+ and Fe3+/Fe2+ redox couples accelerated the electron transfer and formation of ROS. More than 42 % of •OH was generated in the presence of FC-0.3, and the •OH, •O2− and 1O2 were the main ROS that contributed to AMX degradation. The surface OH groups played a key role in the catalytic ozonation. The oxygen vacancies (OVs) played an important role in electron transfer, Ce and Fe were the active sites of electrons transfer following the sequence of (Ce3+ + Fe2+) → (Ce4+ + Fe3+) → (Ce3+ + Fe2+) redox reaction. The degradation pathway investigation and toxicity evaluation revealed that some more toxic intermediates were generated during the ozonation process, and sufficient mineralization is required to meet safe discharge. This study provides reference for the synthesis of new catalysts and insight into the reaction mechanisms in the heterogeneous catalytic ozonation process.

Using nitrate saturated metal–organic frameworks (MOFs) MIL-101-NH2(Fe) as precursors, N, O co-doped carbon/Fe composites (NOC/Fe-MIL) were synthesized by carbonization for activating peroxymonosulfate (PMS) to degrade sulfadiazine (SDZ). N and O species were doped into the carbon matrix by adsorbed nitrate, increasing the degradation rate of SDZ by 2.80 times compared to the original materials (NC/Fe-MIL). N, O co-doping not only increased the charge transfer rate on the materials surface, but also provided more pyridine N, CO groups and defects as main active sites for enhancing the adsorption to PMS indicated by DFT calculations, thus promoting the generation of O2− and 1O2 to degrade SDZ. More importantly, the NOC/Fe-MIL/PMS system still exhibited stable degradation performance in a wide pH range and in the presence of background anions, which can be used in a variety of complex water matrices and regenerated by heating, enabling it to be applied to practical wastewater treatment. This work will provide a general approach for preparing heteroatom modified materials and new insights for exploring critical roles of N and O species in PMS activation.

In this study, specific generation of 1O2 was achieved by activation of peroxymonosulfate (PMS) using N-doped porous carbon with Fe nanoparticles (NPC-Fe), synthesized by carbonizing MIL-88B(Fe) metal-organic frameworks modified with ionic liquid. Fe(II) in the catalyst was found to react with PMS to form •O2−, and Pyridinic N promoted the conversion of •O2− to 1O2. Consequently, the NPC-Fe/PMS reaction system could generate a large amount of 1O2 by the synergistic effect of Fe(II) and Pyridinic N. The system demonstrated excellent performance in a wide pH range for the degradation of contaminants represented by antibiotics. Additionally, the catalyst NPC-Fe had good stability and recyclability. This work provides novel insights for generating 1O2 by activation of PMS for environmental remediation.

Ambient exposure to polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) is suspected to cause adverse human health outcomes. Herein, serum samples from 40 residents in the neighborhood of a municipal solid waste incinerator (MSWI) in the metropolitan area were measured for PCDD/Fs. The mean toxic equivalent (TEQ) concentration of total PCDD/Fs in human serum samples was 16.8 pg TEQ/g lipid. Serum PCDD/F levels were significantly higher in residents adjacent to the MSWI than in those from areas far from the emission source (p < 0.01). In addition, there were no significant associations between serum PCDD/Fs levels and factors, such as gender, age, and BMI in donors. For non-occupationally exposed populations, OCDD and 1,2,3,7,8-PeCDD in serum are available as indicators of total PCDD/Fs and total TEQ, respectively. The atmospheric PCDD/Fs levels were within a relatively low range in areas upwind and downwind of the MSWI. The results of the principal component analysis showed a distinct difference in PCDD/F congener patterns between air and serum samples, suggesting inhalation exposure could have a limited influence on the human body burden. Our findings will deepen the current knowledge of endogenous PCDD/F exposure in urban populations, and also facilitate public health protection strategies near MSWIs.

Mixed-phase TiO2 photocatalysts with different proportions of anatase and rutile have been successfully synthesized in an acidic hydrothermal system, using tartaric acid (C4H6O6) as a phase content regulator and titanium trichloride (TiCl3) as the titanium source. The obtained samples were characterized by X-ray diffraction spectroscopy (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and so on. The phase contents of anatase and rutile in the TiO2 particles were successfully controlled by simply adjusting the molar ratio of C4H6O6 to TiCl3. And the regulation degree could be further controlled by the concentration of sodium chloride (NaCl) in the reaction system. In addition, the effect of the reaction time, hydrothermal temperature and acidity on the phase structure of as-prepared products have also been investigated. A mechanism was proposed to interpret the evolution of the phases based on the experimental results. Finally, the photocatalytic activity of the prepared TiO2 were evaluated by the degradation of Rhodamine B (RhB) and methyl orange (MO) in aqueous solutions. The mixed-phase TiO2 exhibited higher activity than pure phase TiO2, and the catalyst containing 77% anatase and 23% rutile had the highest photocatalytic activity. The enhanced photocatalytic activity could be explained by the mixed-phase effect between anatase and rutile.

Two-chamber microbial fuel cells (MFCs) were exposed to static magnetic field (MF) of field strengths 0 mT, 100 mT, 200 mT, and 300 mT, and the electricity production of the MFCs under the influence of the MF was investigated using electrochemical methods. The results show that the start-up periods of MFCs in MF were shorter than that without. The MFC with a 100-mT MF needed the shortest time (7 days) to obtain a stable voltage output. The maximum power density of 1.56 W m−2 was for a field strength of 200 mT, which was the best among the MFCs. The impact of the MF on the charge transfer resistances (Rct) of the anode, cathode, and whole MFC was analyzed by electrochemical impedance spectroscopy (EIS). A new method was developed to extend the equivalent circuit (EC) model to the whole MFC by connecting the anode and cathode models in series. The simulated results show that anode Rct values are much higher compared than at the cathode. The cell and anode Rct values were reduced by 56.6% and 57.2%, respectively, for the 200-mT MF. It was also found that there is an optimal intensity MF range for the microorganisms.

Anaerobic ammonium oxidation (anammox) combined with partial-denitrification (NO3– → NO2–) is an innovative process for the simultaneous removal of ammonia and nitrate from wastewaters. An efficient method for the selection of partial denitrifying community, which relies on increasing influent salinity, is described. Using this method, a denitratating community was enriched, which showed a nitrite accumulation efficiency higher than 75% as well as a high nitrate conversion efficiency. Community analysis using 16S rDNA indicated that Halomonas became the dominant genus as salinity increased. Metagenomic analysis revealed that there was not a significant difference in reads mapping to downstream denitrification genes in a comparison of samples from cultures with 5% salinity to those without salinity. The majority of the reads mapping to the genes encoding dissimilatory nitrate and nitrite reductases nar and nirS came from Halomonas under high salinity conditions. Two metagenome-assembled genomes taxonomically assigned to Halomonas were obtained, one of which accounted for ∼35% of the reads under high salinity conditions. Both genomes harbored the genes for the complete denitrification pathway. These results indicate progressive onset denitrifiers, a phenotype where nitrite reduction only occurs after nitrate exhaustion, could be successfully enriched with increasing salinity. Progressive onset denitrifiers may be more widespread in natural and artificial habitats than anticipated and are shown here to be valuable for nitrogen mitigating processes.

This study investigated the performance of anaerobic digestion systems using four types of fibrous biofilm carriers, a polypropylene, a polyester, a polyamide, and a polyurethane fiber material. The biogas and methane production, pH, chemical oxygen demand, total solids content, volatile solids content, residual coenzyme F420, and microbial community compositions were determined during the experimental runs. Furthermore, scanning electron microscopy was employed to identify the microbial consortium and examine their attachment onto the surface of the four fibrous biofilm carriers. The polypropylene fiber system maintained the highest biogas and methane production in the reactor, which was 44.80% and 49.84% higher than that noted in the control, respectively, during the entire anaerobic fermentation cycle. Meanwhile, the polypropylene fiber system exhibited the highest TS, VS, and COD removal efficiency. The results of high-throughput sequencing indicated that the dominant species in the polypropylene fiber system were Methanoregula and Methanobacterium.

An inverse opal TiO₂/g-C₃N₄ composite with excellent photogenerated electron–hole separation efficiency and enhanced visible light absorption efficiency was constructed.

Optimizing the heterojunction structure of semiconductor photocatalysts is vital for utilizing their abilities in organic matter degradation.

To investigate biological effects of bisphenol A (BPA) over the long term, the model animal Caenorhabditis elegans was used to conduct the chronic exposure. C. elegans were exposed to BPA (0.0001-10 μM) from L4 larvae to day-10 adult in the present chronic toxicity assay system. Multiple endpoints at the physiological (growth, locomotion behaviors and lifespan), biochemical (lipofuscin accumulation), molecular (stress-related genes expressions), and population (population size) levels were examined. At the physiological level, BPA exposure induced significant negative effects on the indicators. Among the endpoints, head thrash was most sensitive and the detection limit was 0.001 μM. At the biochemical level, BPA exposure induced no significant effects on lipofuscin accumulation. At the molecular level, BPA induced strong stress responses in vivo. At the population level, the population size was significantly decreased in the treatment groups from 0.1 to 10 μM. Compared to the previous short-term toxicity evaluation, long-term exposure to BPA induced a more obvious response at the same concentration, and the phenomenon might be due to cumulative toxic effects. By the Pearson correlation analyses, cep-1 was speculated to act as an important role in BPA-induced chronic toxicity on C. elegans.

The aim of this work was to enhance methane production from swine manure anaerobic digestion (AD) with in-situ formed graphene in microbial electrolysis cell (AD-MEC). The AD-MEC for in-situ graphene exfoliation incorporated a carbon felt anode and a titanium mesh cathode with an applied voltage of 2.5 V. Atomic force microscopic and Raman analyses confirmed that the graphene was in-situ formed. Voltage stimulation (1 h per day) and graphene production enhanced AD efficiency by promoting direct interspecies electron transfer between AD microorganisms. The increased biomass owing to enrichment of AD microorganisms on the carbon felt could also enhance AD efficiency. The voltage-graphene group (VGG) greatly enhanced the biogas yield (356.49 m3/t dry swine manure) and methane yield (222.17 m3/t dry swine manure), which were 41.49% and 60.89% higher than that of the control group, respectively. Microbial community analysis identified the dominant methanogens in the VGG system as Methanosarcina and Methanobrevibacter, while only Methanosarcina was dominant in the control system. Network analysis showed that the VGG system established a narrower niche than the control system, and microorganisms trended to gather more in the module.

The feasibility of achieving stable nitritation inoculating with activated sludge by adding formic acid was studied in this work. Short-term batch effects of formic acid on nitrification showed that the nitrite accumulation ratio (NAR) significantly increased from 0.3% to 83.7% with an increase of formic acid concentration from 0 to 50 mM at an initial ammonia concentration of 75 mg·L-1, which was demonstrated to be due to the inhibition of nxrB transcription in nitrite oxidizing bacteria (NOB). The long-term effects of formic acid at 30 mM were constantly monitored in an aerobic sequencing batch reactor. During 27 days of operation, the NAR was rapidly raised and maintained approximately 90%. What's more, in the following 52 days without addition of formic acid, the NAR was kept above 91.3%. The sustained suppression of NOB genus Nitrospira coupling nxrB inhibition was the main reason to maintain stable nitritation. These results supported the feasibility of formic acid as an efficient nitritation regulator, thus providing a new approach for the development of the BNR process via nitrite pathway.

The present study was performed to evaluate the neurobehavioural deficit induced by nonylphenol (NP), a well-known xenobiotic chemical. The neurotoxic mechanism from oxidative stress and serotonin-related progress was also investigated. Caenorhabditis elegans was exposed at different levels of NP ranging from 0 to 200 μg L−1 for 10 days. The results revealed that from a relatively low concentration (i.e., 10 μg L−1), significant effects including decreased head thrashes, body bends and forging behaviour could be observed, along with impaired learning and memory behaviour plasticity. The level of reactive oxygen species (ROS) in head was significantly elevated with the increase of NP concentrations from 10 to 200 μg L−1. Through antioxidant experiment, the oxidative damage caused by NP restored to some extent. At a NP concentration of 200 μg L−1, the significant increased expression of stress-related genes, including sod-1, sod-3, ctl-2, ctl-3 and cyp-35A2 gene, was observed from integrated gene expression profiles. In addition, in comparison with wild-type N2 worms, the ROS accumulation was increased significantly with the mutation of sod-3. Tryptophan hydroxylase (TPH) in ADF and NSM neurons sharply decreased at the concentrations of 10–200 μg L−1. The transcription of TPH synthesis-related genes and serotonin-related genes were both suppressed, including tph-1, cat-1, cat-4, ser-1, and mod-5. Overall, these results indicated that NP could induce neurotoxicity on Caenorhabditis elegans through excessive induction of ROS and disturbance synthesis of serotonin. The conducted research opened up new avenues for more effective exploration of neurotoxicity caused by NP.

A novel hybrid nanoreactor with spatially separated co-catalysts (SH-CD-Au@CdS@MnOx) was successfully synthesised to remove bisphenol-A (BPA) from water by visible light. The photooxidation intermediates, degradation pathway of BPA and the enhancement mechanism were investigated in particular. Gold (Au) nanoparticles modified with SH-β-cyclodextrin and MnOx nanoparticles were selectively decorated on the interior and exterior surface of hollow CdS nanoreactors, respectively. The directed migration of photogenerated electrons and holes induced by spatially separated co-catalysts lead to high utilization of light, and SH-β-cyclodextrin modification makes catalytic active sites more accessible for oxidation intermediates. Compared with pristine CdS, the hybrid nanoreactor increased the BPA photooxidation reaction rate and the TOC removal efficiency by 5.6-fold and 3.6-fold, respectively. Moreover, the toxic intermediates, such as phenol, were further degraded by visible light. Molecular orbital calculation predicted that the sites on BPA molecule values of (FED2HOMO + FED2LUMO) can be easier attacked by the radical, whereas atoms with higher values of 2FED2HOMO can easily be extracted into electrons. Thus, SH-CD-Au@CdS@MnOx can provide a new strategy for the high-efficiency photodegradation of endocrine disrupter compounds in advanced water treatments.

The main objective of this study was to optimize bioleaching process parameters for high co-extraction of base metals (Cu, Ni, Zn, and Cr) from hazardous electroplating sludge using an adapted microbial consortium and to explore the relevant bioleaching mechanisms. Microbial cultivation and sludge bioleaching were separated. The effect of the relevant process parameters (i.e., bulk pH, pulp density, and Fe2+ concentration) on the extraction of four selected metals through bioleaching by an adapted microbial consortium was investigated in a 1 L stirred tank reactor. Results indicated that maximum metal solubilization (>95.6% for each of Cu, Zn, and Ni, and 90.3% of Cr) was achieved at a bulk pH of 2.0, Fe2+ of 9.0 g/L, and pulp density of 15% (w/v). Bioleaching kinetics of the selected metals was described by a modified shrinking core model. This indicated that the interfacial transfer and diffusion across the solid film layer was the rate controlling step and controlled the dissolution kinetics. Data from bioleaching and chemical leaching systems showed that bioleaching had some advantages over simple chemical leaching. The mechanisms of improved Cu, Ni, Zn, and Cr extraction by bioleaching were demonstrated. Bioleaching improved metal release, especially from the residual fraction, as indicated by Community Bureau of Reference (BCR) three-stage sequential extraction analysis. Most of the Cu, Ni, and Zn extraction was attributed to H+ attack, as these metals were primarily distributed in the water/acid soluble and exchangeable fractions, along with Fe and Mn oxyhydroxides (>72.3%). For the extraction of Cr, besides H+, microorganisms and Fe3+ were also responsible. They improved Cr extraction, especially from the residual fraction. These findings indicate that bioleaching with an adapted microbial consortium appears promising for recycling and reutilizing valuable heavy metals from hazardous electroplating waste.

• Fe 2+ /PMS photo-Fenton-like performance could be improved by IO WO 3 cocatalyst. • 1 O 2 is proved main ROS in this heterogeneous co-catalytic photo-Fenton-like process. • 1 O 2 can be directly converted from SO 4 − and O 2 − radicals without OH intermediate. • The efficient photogenerated carrier catalyst can improve photo-Fenton activity. Singlet oxygen ( 1 O 2 ) as an important reactive oxygen species (ROS) has broad application prospects in the fields of organic synthesis, cell repair, environmental remediation et al . However, the mechanism of the 1 O 2 formation in the Fe 2+ /PMS Fenton-like system, which is directly transformed from O 2 − or generated by OH as an intermediate, is still a mystery. Herein, we designed an inverse opal WO 3 (IO WO 3 ) co-catalytic photo-Fenton-like system, which can finish RhB (20 mg·L −1 ) degradation within 6 min. And the optimal condition of pH, light intensity, FeSO 4 ·7H 2 O dosage, PMS dosage, cocatalyst dosage were also explored in this work. The high-efficiency photogenerated long lifetime charge carriers produced by IO WO 3 cocatalyst under photocatalytic process can directly make a conversion from SO 4 − and O 2 − to 1 O 2 without OH intermediate in the solution. Furthermore, the IO WO 3 cocatalyst addition can improve the reduction of Fe 3+ /Fe 2+ ions to enhance activation of PMS molecule. As for the interconnected periodic macroporous framework of inverse opal WO 3 would help to improve mass transfer and light harvest in the photo-Fenton-like process. This facile synthesized material with recyclable and stable co-catalytic activity for the contaminant remediation, and the selective generation of 1 O 2 in the Fe 2+ /PMS process, will highlight its huge application in environmental potential.

Metal-free carbon-based catalysts hold great promise for the degradation of organic pollutants by peroxymonosulfate (PMS) activation because they avoid the negative effects of metal catalysts such as harmful metal ions leaching. However, these carbon-based catalysts are limited by their high cost and complex synthesis, and the mechanisms for the activation of PMS are unclear. Herein, the N-rich carbon catalysts (GCN-x) derived from glucose and g-C3N4 were facilely synthesized by hydrothermal treatment and carbonization to explore the mechanism of PMS activation. The nitrogen content of catalysts could be adjusted by simply altering the ratio of glucose and g-C3N4. GCN-2.4 with a ratio of glucose and g-C3N4 of 2.4 displayed the highest efficiency for the degradation of pollutants represented by Levofloxacin. The electron paramagnetic resonance and quenching experiments demonstrated that the non-radical pathway was dominant in Levofloxacin degradation and singlet oxygen (1O2) was the main active specie. Further, we found 1O2 was generated from superoxide radical (• O2-) which has rarely been studied. Levofloxacin degradation rate was shown to be positively correlated with both the amount of graphitic N and pyridinic N. Graphitic N and pyridinic N were identified as the catalytic sites. The GCN-2.4/PMS system could also remove multifarious contaminants effectively. Overall, this research advances understanding of the role of N species in PMS activation and has potential practical application in wastewater treatment.

This study focused on acclimating a microbial enrichment to biodegrade benzene, toluene, ethylbenzene and xylenes (BTEX) in a wide range of salinity. The enrichment degraded 120 mg/L toluene within 5 d in the presence of 2 M NaCl or 150 mg/L toluene within 7 d in the presence of 1–1.5 M NaCl. PCR–DGGE (polymerase chain reaction–denatured gradient gel electrophoresis) profiles demonstrated the dominant species in the enrichments distributed between five main phyla: Gammaproteobacteria, Sphingobacteriia, Prolixibacter, Flavobacteriia and Firmicutes. The Marinobacter, Prolixibacter, Balneola, Zunongwangia, Halobacillus were the dominant genus. PCR detection of genotypes involved in bacterial BETX degradation revealed that the degradation pathways contained all the known initial oxidative attack of BTEX by monooxygenase and dioxygenase. And the subsequent ring fission was catalysed by catechol 1,2-dioxygenase and catechol 2,3-dioxygenase. Nuclear magnetic resonance (NMR) spectroscopy profiles showed that the bacterial consortium adjusted the osmotic pressure by ectoine and hydroxyectoine as compatible solutes to acclimate the different salinity conditions.

Using silylated carbon dots as the framework fluorogen, periodic mesoporous organosilica (PMO) nanoparticles (NPs) possessing unimpeded, ordered meso­pores, and excellent one- and two-photon excitation fluorescence properties are obtained. These novel, fluorescent NPs serve as platforms for the design and fabrication of ratiometric sensors, multichannel traceable drug delivery vehicles, and efficient photocatalysts.

Carbon dots (CD) and Ti species were assembled in the mesoporous silica matrix by a one-pot co-condensation strategy. The CD and Ti in the silica matrix were demonstrated to interact in two ways: on the one hand, part of the carbon in CD was doped into the Ti species; on the other hand, CD worked as photosensitizers for Ti species. The synergy effect between CD and Ti in the silica matrix along with the unique physical properties of the composite including ordered pore channels, large surface area and wide-range light absorption from UV to near IR made this composite be an excellent photocatalyst, as demonstrated by the photocatalytic degradation of azo dye acid orange 7. In addition to the degradation of organic pollutant, this newly developed mesoporous composite is expected to have promising applications in various areas related to environment and energy such as photoreduction of CO2 and photocatalytic H2 production.

Tetrabromobisphenol A (TBBPA) is a commonly used brominated flame retardant, which has a wide range of toxic effects on organisms. This study investigated the cytotoxic effects on human hepatocytes (L02 cells) after treated with 0, 5, 10, 20, and 40 μM of TBBPA. Results showed that TBBPA significantly increased intracellular reactive oxygen species (ROS), malondialdehyde (MDA) and the ratio of oxidized/reduced glutathione (GSSG/GSH) dose-dependently. TBBPA also decreased the cell mitochondrial membrane potential (MMP), caused the release of cytochrome C (Cyt C) to cytoplasm and promoted the expression of caspase-9 and caspase-3, and finally increased the level of apoptosis. The ROS inhibitor N-acetyl-L-cysteine (NAC) relieved the oxidative stress responses, and prevented the decrease of MMP and increase of apoptosis. In addition, TBBPA promoted the expression of antioxidant genes related to Nrf2, such as quinone oxidoreductase 1 (NQO1), catalase (CAT), and heme oxygenase 1 (HO-1). Oxidative stress initiated by TBBPA, activated mitochondrial apoptosis and Nrf2 pathway, and increased the degree of apoptosis in L02 cells.

In order to understand how bisphenol A (BPA) exposure acts on the evolutionary dynamics of populations and changes of stress response across generations, the model animal Caenorhabditis elegans was used to conduct the multigenerational testing. Multiple endpoints at the physiological (growth, reproduction, and locomotion behaviors) and molecular (stress-related gene expressions) levels were examined by multigenerational exposure to low-concentration BPA (0.001-10 μM) across four generations. The results showed that changes of physiological-level effects across four generations varied in magnitude and direction, depending on the exposure concentrations. C. elegans individuals in the first generation grew smaller, moved slower, and produced less offsprings than the controls by BPA exposure. As for each trait tested, the first generation response could be commonly mirrored in the subsequent generations at the highest concentration of 10 μM. However, at lower concentrations, response of parental generation was a relatively poor predictor of the effects on progeny, as acclimation or cumulative damage could occur in the subsequent generations. The integrated gene expression profiles visually illustrated that the tested gene expressions at low concentrations (0.001-0.01 μM) were more obviously changed in both G1 and G4 generations, and the G1 generation showed a much greater degree of increase in stress-related gene expressions than the G4 generation. The multigenerational toxicity data emphasize the need of considering biological effects over multiple generations to conduct accurate assessment of environmental risks of toxicants on population dynamics.

The aerobic granular sludge (AGS) dominated by halophilic microorganisms, was successfully cultivated in a lab-scale sequencing batch reactor (SBR) under varying salinity levels (from 0% to 6% (w/v)). Removal performance of AGS improved with the increase of salinity and increased up to 42.86 mg g-1 VSS h-1 at 6% salinity. Increased salinity resulted in better settling performance of AGS in terms of the sludge volume index (SVI), which was initially 148.80 mL/g at 0% salinity and gradually decreased to 59.1 mL/g at 6% salinity. The increase of salinity stimulated bacteria to secret excessive extracellular polymeric substances (EPS), with its highest production of 725.5 mg/(g·VSS) at 5% salinity. The total protein (PN) exhibited highly positive correlation with the total EPS (R = 0.951), indicating that selective secretion of some functional PN played a key constituent in resisting the external osmotic pressure and improving sludge performance. Salinicola, accounted for up to 91% relative abundance at 6% salinity, showed the high positive correlation (R = 0.953) with salinity. The enrichment of such halophilic or halotolerant microbial community assured both stable and improved removal performance in the AGS system. The enrichment of salt response pathways and altered metabolic processes for salt-tolerant bacteria indicated that the microbial community formed special metabolic pattern under long-term hypersaline stress to maintain favourable cellular activity and removal performance.

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) has been frequently detected in environmental media and biological samples. However, knowledge of its adverse health consequences is limited. In the current study, Caenorhabditis elegans (C. elegans, L1 larvae) were exposed to TDCPP at environmentally relevant concentrations (control, 0.1, 1, 100 and 1000 μg L-1) for 72 h to explore any association between TDCPP and the aging process. Some of the degenerative age-related indicators were observed, including locomotion behaviors and lifespan. As crucial biomarkers of aging, the accumulation of lipofuscin, and lipid peroxidation (LPO) products exemplified by 4-hydroxynon-2-enal (4-HNE) were detected. This product forms as a result of oxidative stress, as confirmed by an N-acetyl-L-cysteine (NAC) pharmacological assay. Moreover, a significant increase in reactive oxide species (ROS) production in a dose-dependent manner using a fluorescent probe was observed. For the underlying molecular mechanism of the above aging phenotypes, significantly upregulated transcription of genes related to antioxidant systems, especially a subset of glutathione S-transferase (gst-5, gst-6, gst-9, gst-10, gst-19, gst-24, gst-26, gst-29, gst-33, and gst-38), was found by RNA-Seq and further confirmed by RT-qPCR. The elevated glutathione S-transferase (GST) was attributed to the significant increase in 4-HNE because mutations in gst-5 and gst-24 inhibited the conjugation of GSTs with 4-HNE. Therefore, GST play an indispensable role in the detoxification process of TDCPP exposure and further confirmed LPO accumulation at the molecular mechanism level. In conclusion, TDCPP accelerated the aging process induced by the LPO products, 4-HNE, response to reactive oxidative species in C. elegans.

In this work, inverse opal (IO) structure construction and phosphorus doping were combined to modify carbon nitride (g-C₃N₄) for the photocatalytic reduction of CO₂.

Applications of noble metal decorated photocatalytic nanomaterials are restricted by its high cost. In this study, carboxymethyl β-cyclodextrin (CM-β-CD), as an alternative to gold nanoparticle, was used to modified titanium dioxide (CM-β-CD-P25) to accelerate photoelectron transmission and enhance the organic contaminants removal from water. Several of emerging organic contaminants, such as bisphenol A (BPA), phenol and sulphanilamide (SA), were used to evaluate their photocatalytic activities. Carboxymethyl-β-cyclodextrin not only provide hydrophobic sites to entrap organic contaminants but also provide a “bridge” for accelerated transmission of photogenerated charges without introducing the recombination interface. Consequently, 91.6 % of BPA, 71.9 % of phenol and 97.1 % of SA could be removed by CM-β-CD-P25(2:1) under 1 h UV light irradiation. The photooxidation rate constant of BPA, phenol and SA by CM-β-CD-P25(2:1) were 0.039 min−1, 0.021 min−1 and 0.062 min−1, respectively, which are much higher than that of pristine P25 and Au-P25. Moreover, the photocatalytic activity of CM-β-CD-P25(2:1) remains almost unchanged in repeated cycle test owing to its high stability. The reasonable mechanism of CM-β-CD-P25 were investigated. CM-β-CD-P25 hybrid nanoparticles completely surpasses Au-P25 in organic contaminants removal, and shows great potential to replace noble metal as mediator.

Anaerobic digestion (AD) systems with high substrate concentrations are characterized by high viscosity, which affects material and energy transfer efficiencies, thereby influencing methane production efficiency. In this study, adding granular activated carbon (GAC) and increasing the temperature decreased the viscosity by 4.56–10.19% and 27.13–28.85%, respectively, and improved AD efficiency. Adding GAC and increasing the temperature enhanced the methane yields by 34.37–38.15% and 25.60–28.31%, respectively. Distance-based redundancy analysis showed that the viscosity, temperature, and GAC had the greatest effects on the composition of the microbial community. The dominant bacteria in the medium-temperature AD system at the phylum level belonged to Firmicutes, Bacteroidetes, and Euryarchaeota. In addition to the dominant bacteria in the medium-temperature AD system, the thermophilic phylum Thermotogae was abundant in the high-temperature AD system. Moreover, the relative abundance of Euryarchaeota, which contained most of the methanogens, was higher in the high-temperature AD system than in the medium-temperature AD system.

Aerobic granular sludge (AGS) technology has been recognized as a promising alternative to alleviate the osmotic stress of hypersaline wastewater. However, the response of AGS process to composite hypersaline wastewater on removal performance and populations was yet to be understood. In this work, two sequenced batch reactors were operated in parallel in absence (R0) and presence (R1) of high concentration sulfate as proxy for single and mixed salts (30 g salt·L−1) respectively. Results demonstrated that the presence of sulfate in hypersaline wastewater enhanced chemical oxygen demand (COD) and total nitrogen (TN) removals of 95.3% and 65.5% respectively with lower accumulations of nitrite. High-throughput 16 S rRNA gene sequencing technique elucidated that Denitromonas (31.6%) and Xanthomarina (17.0%) were the more dominant genera in AGS response to mixed salts with high sulfate and laid the biological basis for strengthening removal performance. The enrichment of halophilic Luteococcus (23.5%) in the AGS surface indicated the potential role of mixed salts in shaping the physical properties and surface population structure of AGS. Our work could facilitate the potential applications of AGS technology for industrial hypersaline wastewater treatment with complicated compositions.

Semiconducting minerals (such as iron sulfides) are highly abundant in surface water, but their influences on the natural photochemical process of contaminants are still unknown. By simulating the natural water environment under solar irradiation, this work comprehensively investigated the photochemical processes of anthracene (a typical Polycyclic Aromatic Hydrocarbons) in both freshwater and seawater. The results show that the natural pyrite (NP) significantly promotes the degradation of anthracene under solar illumination via 1) NP induced photocatalytic degradation of anthracene, and 2) Fenton reaction due to the NP induced photocatalytic generation of H2O2. The material characterization and theoretical calculation reveal that the natural impurity in NP enlarges its band gap, which limits the utilization of solar spectra to shorter wavelength. The contribution of generated reactive intermediates on anthracene degradation follows the order of 1O2 >OH > O2- in freshwater and O2- >1O2 >OH in seawater. The photochemically generated H2O2 is a vital source for OH generation (from Fenton reaction). The steady-state concentration of OH, 1O2 and O2- in freshwater were monitored as 3.0 × 10-15 M, 1.1 × 10-13 M, and 4.5 × 10-14 M, respectively. However, the OH concentration in seawater can be negligible due to the quenching effects by halides, and the 1O2 and O2- concentrations are higher than that in freshwater. An anthracene degradation kinetic model was built based on the experimentally determined reactive intermediates concentration and its second order rate constant with anthracene. Moreover, the anthracene degradation pathway was proposed based on intermediates analysis and DFT calculation, and its toxicity evolution during the photochemical process was assessed by quantitative structure-activity relationship (QSAR) based prediction. This finding suggests that the natural semiconducting minerals can affect the fate and environmental risks of contaminants in natural water.

The utilization of near-infrared (NIR) light with strong photothermal effect in photo-Fenton or Fenton-like systems for the degradation of organic pollutants is always ignored. In this study, we have synthesized a novel photothermal Fenton-like catalyst (Co3O4/PDA) to activate peroxymonosulfate (PMS) for the degradation of antibiotics. The Co3O4 in the nanocomposite acts as a PMS activator, while unexpectedly, PDA was found to accelerate the redox cycle of Co2+/Co3+. Both Co3O4 and PDA are black-colored photothermal materials with excellent NIR absorption properties. During the degradation process, the light-to-heat conversion ability of Co3O4 and PDA enables a higher temperature, which innovatively boosts the rate of PMS catalytic activation. Mechanistic studies revealed that the increased temperature effectively promotes the heterogeneous catalytic PMS activation by Co3O4/PDA. As a result, the Co3O4/PDA + PMS + NIR system exhibits greatly enhanced degradation performance. Furthermore, this degradation system demonstrates strong tolerance to different operation conditions, and the catalyst exhibits good stability in cycling tests. These results demonstrate the favorable application prospects of this photothermal Fenton-like system in environmental water remediation. The findings also contribute valuable insights towards the development of efficient strategies for the photothermal activation of PMS.

In this study, a novel hybrid process involving stepwise coagulation and intermediate ozonation in the presence of granular activated carbon (GAC/O3) was employed to remove effluent organic matter (EfOM) from bio-treated textile wastewater. Removal behavior of EfOM in different processes, including biodegradability, hydrophobic and hydrophilic property, and apparent molecular weight (AMW) distribution, were evaluated as well. When the polyaluminum chloride (PACl) dose of 25 mg L−1 as Al was used in both pre-coagulation (pH 8.0) and post one (pH 5.5), and the ozone dose of 3.1 mg O3 mg−1 COD was applied in GAC/O3 (GAC 10 g L−1) lasting 5 min, the superior removal efficiencies of water quality parameters like turbidity, color, COD, DOC and UV254 were 95.8%, 97.5%, 88.1%, 68.7% and 90.5%, respectively. Results also showed that GAC/O3 not only gave the efficient decolorization and DOC removal, but also enhanced the treatability of biodegradable and hydrophilic organics of AWM in 1–10 k Da by post coagulation, likely due to the effective removal of colored and hydrophobic organics in AMW > 1 k Da via pre-coagulation. Therefore, the hybrid process applying appropriate operational parameters was proved to be an attractive strategy in the wastewater reclamation.

With the development and operation of the bench-scale opposed multi-burner gasification system and the application of advanced visualization techniques, the particle deposition characteristics in a gasifier has been studied. The particle deposition characteristics are mainly divided into four different types: particles impact and adhere, particles impact and rebound, particles detach after adherence, and particles impact and break up. The high-temperature and low-temperature particle deposition characteristics are discussed separately. The probability of low-temperature particle impact and adhere (39.50%) is approximately the same as that of impact and rebound (45.50%), and the proportion of adhered particles detach from refractory wall is 12.50%. The probability of high-temperature impact and adhere is 75.70%, which is much higher than that of impact and rebound (21.10%), whereas only 0.80% of high-temperature particles detach after adherence. The proportion of particle break up is almost the same for both high- and low-temperature particles, with a percentage of ~2.50%.

Alkane-degrading bacteria are crucial in the bioremediation of petroleum contamination from soil and groundwater. The alkane monooxygenase (alkB) gene encoding the Alk enzyme involved in aerobic degradation is a potentially functional gene biomarker for the detection of alkane-degrading bacteria. This study describes a denaturing gradient gel electrophoresis (DGGE) assay to facilitate the rapid and sensitive detection of alkB genes in wastewater from oilfield. The results showed that the presence of a considerable genetic diversity of alkB genes in the wastewater as evidenced by a total of 13 unique DNA bands detected. These alkB genes belong to nine genera, including Acinetobacter, Alcanivorax, Acidisphaera, Burkholderia, Geobacillus, Marinobacter, Mycobacterium, Pseudomonas, Rhodococcus and Xanthobacter. The abundance of alkane-degrading bacteria and total bacteria was calculated to range from 1.46 × 103 to 9.89 × 104 cell ml−1 and from 1.18 × 104 to 6.29 × 105 cells ml−1, respectively. The distribution of alkane-degrading bacteria was positively correlated with the environmental temperature and the specific types of n-alkanes in the wastewaters. Our results suggest that alkB-based DGGE methods could describe the diverse alkane-degrading bacteria in oil-degrading community, which may improve the understanding of the treatment for oil-polluted wastewater.

The effective disposal of waste cutting fluid has received increasing attention in recent years. This study focuses on the treatment of waste cutting fluid by freeze-thaw method. The influences of freezing medium, freezing temperature, freezing time, NaCl content and pH on treatment efficiency were studied. The COD removal rate of waste cutting fluid was about 80% and oil recovery reached 3700 mg/L at the freezing temperature of −8 °C for 8 h without NaCl addition or pH adjustment. The micrograms of initial and treated waste cutting fluid showed that the particles of oil droplets in wastewater were significantly larger after freeze-thaw process and easier to gather and separation. Infrared spectroscopy studies indicated that the oil recovered from waste cutting fluid precipitation was mainly composed of esters. Up to 3.7 kg fat extract was recovered from 1 m3 of waste cutting fluid, while the required power of this freezing process is 42.90 kW h by theoretical calculation. Thus, freeze-thaw method appears to be effective and feasible for waste cutting fluid treatment.

A polymer composite consisting of g-C₃N₄ and PDPB with efficient and stable photocatalytic performance for degradation of organic pollutants has been developed.

In order to gain insights into the chronic effects and mechanisms of hexabromocyclododecane (HBCD), the animal model Caenorhabditis elegans (C. elegans) was chosen for toxicity study. Multiple endpoints, including the physiological (growth and locomotion behaviors), biochemical (reactive oxygen species (ROS) production, lipofuscin accumulation, and cell apoptosis), and molecular (stress-related gene expressions) levels, were tested by chronic exposure for 10 d to low concentrations of HBCD (0.2 nM-200 nM). The results revealed that chronic exposure to HBCD at concentrations more than 20 nM would significantly influence the growth, locomotion behaviors, ROS formation, lipofuscin accumulation, and cell apoptosis of nematodes. Treatment with antioxidants of ascorbate and N-acetyl-l-cysteine (NAC) suppressed the toxicity induced by HBCD. The integrated gene expression profiles showed that the chronic exposure to 200 nM of HBCD significantly increased the expression levels of stress-related genes (e.g., hsp-16.2, hsp-16.48, sod-1, sod-3, and cep-1 genes). Among these genes, the sod-1, sod-3, and cep-1 gene expressions were significantly correlated with HBCD-induced physiological effects by the Pearson correlation test. The mutations of sod-3 and cep-1 induced more severe toxicity compared to wild-type nematodes. Therefore, HBCD exposure induced oxidative stress by ROS accumulation and cell apoptosis, which resulted in HBCD-induced toxicity on nematodes, and sod-3 and cep-1 played important roles in protecting nematodes against HBCD-induced toxicity.

In order to understand multi-generational effects and changes of stress response by hexabromocyclododecane (HBCD) exposure, the animal model Caenorhabditis elegans was chosen for toxicity study. Multiple endpoints, including the physiological levels (growth, reproduction, and locomotion behaviors), stress-related gene expressions, reactive oxygen species (ROS) production and degree of cell apoptosis, were evaluated on exposed nematodes and their progeny. Prolonged exposure to HBCD at concentrations of 2 nM–200 nM caused adverse physiological effects in the parental generation (F0), and these effects were also observed in the offspring under HBCD-free conditions (F1). HBCD-induced toxicities could be transferred from parent to offspring. The integrated gene expressions profiles showed that exposure to HBCD at concentrations of 20–200 nM resulted in obvious changes in stress-related gene expressions, which were more increased in F0 generation than in F1 generation. The increased expressions were pronounced in several genes related to oxidative stress and cell apoptosis, e.g., hsp-16.2, hsp-16.48, sod-1, sod-3 and cep-1 genes. Exposure to 200 nM of HBCD could significantly increase ROS production and degree of cell apoptosis in the F0 and F1 generations. Therefore, it was speculated that HBCD exposure induced oxidative stress and cell apoptosis, which resulted in the adverse physiological effects. This finding is helpful for understanding the multi-generational effects and evaluating the potential risk of HBCD.

Nitrous oxide (N2O) emissions from anammox-based processes are well documented but insight into source of the N2O emission in high-rate anammox granular sludge reactors (AGSR) is limited. In this study, metagenomics and fed-batch experiments were applied to investigate the relative contributions of anammox granules and flocs to N2O production in a high-rate AGSR. Flocs, which constitute only ~10% of total biomass contributed about 60% of the total N2O production. Granules, the main contributor of nitrogen removal (~95%), were responsible for the remaining ~40% of N2O production. This result is inconsistent with reads-based analysis that found the gene encoding clade II type nitrous oxide reductase (nosZII) had similar abundances in both granules and flocs. Another notable trend observed was the relatively higher abundance of the gene for NO-producing nitrite reductase (nir) in comparison to the gene for the nitric oxide reductase gene (nor) in both granules and flocs, indicating nitric oxide (NO) may accumulate in the AGSR. This is significant since NO and N2O pulse assays demonstrated that NO could lead to N2O production from both granules and flocs. However, since anammox bacteria, which were shown to be in higher abundance in granules than in flocs, have the capacity to scavenge NO this provides a mechanism by which its inhibitory effects can be mitigated, limiting N2O release from the granules, consistent with experimental observation. These results demonstrate flocs are the main source of N2O emission in AGSR and provide lab-scale evidence that NO-dependent anammox can mitigate N2O emission.

A double-chamber self pH-buffer microbial fuel cell (MFC) was used to investigate the effect of dissolved oxygen (DO) concentration on cathodic nitrification coupled with anodic denitrification MFC. It was found that nitrogen and COD removal, electricity generation were positively correlated with DO concentration in the cathode chamber. When total inorganic nitrogen of influent was 202.51 ± 7.82 mg/L at DO 6.8 mg/L, the maximum voltage output was 282 mV and the maximum power density was 149.76 mW/m2. After 82 h operation, the highest removal rate of total inorganic nitrogen was 91.71 ± 0.38%. Electrochemical impedance spectroscopy (EIS) test showed that the internal resistance of the reactor with different DO concentration was related to the diffusion internal resistance. The data of bacterial analysis in the cathode chamber revealed that there were not only ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), but also a large number of exoelectrogens. Compared with the traditional biological denitrification and related MFC denitrification research, this method does not need pH-buffer solution and external circulation device through the anion exchange membrane (AEM). It can generate electricity and remove nitrogen simultaneously, and the oxygen utilization rate in the cathode can also be enhanced.

Efforts to produce aerobic granular sludge (AGS) for high-efficient and stable nutrient removal in high saline wastewaters have gained much attention recently. This study was undertaken to describe the phase-related characteristics of the rapid formation of glucose-fed salt-tolerant AGS (SAGS) generated from common municipal activated sludge using metagenomic approaches. The time needed for SAGS formation is about 11 days in a multi-ion matrix salinity of 3%. There were three distinct developmental phases during sludge maturation which were designated: I) the salinity adaptation phase (days 1-2), II) the particle-size transition phase (days 3-5) and III) the maturation and steady-state phase (days 6-11), respectively. Genome-based analysis revealed that during the phase I, members of the genus Mangrovibacter, which has the potential to secrete extracellular polymeric substances (EPS), dominated during the formation of initial SAGS aggregates. During phase II, fungi of the class Saccharomycetes, in particular the genus Geotrichum, became dominant and provided a matrix for bacterial attachment. This mutualistic interaction supported the rapid development and maintenance of mature SAGS. This work characterizes a robust approach for the rapid development of SAGS for efficient saline sewage treatment and provides unique insight into the granulation mechanism occurring during the development process.

In this study, Fe3O4@TiO2 decorated reduced graphene oxide (RGO) nanosheets were synthesized by loading iron oxide on the surface of RGO nanosheets and subsequently coating by titanium oxide, which can be employed as the persulfate (PS) activator and high-performance adsorbent toward thallium (Tl). PS could be effectively activated by the Fe3O4@TiO2 decorated RGO nanosheets due to the presence of RGO and Fe(II), resulting in the rapid oxidation of Tl(I) to Tl(III). The removal of Tl(I) was found to be pH-dependent, with the removal efficiency of more than 88.5% in the pH range of 8.0–12.0 at the optimal PS dosage of 10 mM and material dosage of 0.2 g/L. The surface precipitation of Tl2O3 and enhanced adsorption affinity toward Tl were deduced to be main mechanisms for the extremely efficient removal of Tl(I) ions during the oxidation and adsorption hybrid process. The maximum removal capacity of the material at pH 8.0 was estimated as 673.2 mg/g based on the fitting result from the Langmuir model. Approximately 94.7% of ultimate removal capacity could be accomplished within the first 10 min at the initial Tl concentration of 8.5 mg/L. The PS catalytic oxidation coupled with the adsorption technique using the prepared Fe3O4@TiO2 decorated RGO nanosheets were proven to be a promising approach for Tl(I) removal from water.

Biological nitrogen removal is the most prevalent wastewater nitrogen removal process but nitrification limits the rate of the whole process mainly due to the low efficiency of oxygen transfer. In this study, clean-water oxygenation tests, batch tests, long-term operational tests and metagenomic analyses were applied to assess the effects of micro-nano aeration on nitrification. The oxygen transfer coefficient (KLa), oxygen transfer rate (OTR) and oxygen transfer efficiency (OTE) were determined to be 0.56 min−1, 0.36 kg·m−3·h−1 and 71.43%, respectively during micro-nano-bubble aeration. Impressively, these values were 15 times greater than those of conventional aeration. The results of batch tests and long-term operation experiments found that the ammonia removal rate of micro-nano aeration was 3.2-fold that of conventional aeration. The energy cost for micro-nano aeration was calculated to be 3694.5 mg NH4+-N/kW·h, a 50% energy saving in comparison to conventional aeration. In addition, the nitrite accumulation ratio in the Micro-nano (MN) reactor was 1.5 that of the Conventional (CV) reactor. Metagenomic analysis showed that after long-term operation in micro-nano aeration, the abundances of genes encoding ammonia monooxygenase (amoA) and hydroxylamine oxidoreductase (hao) was more than 8-fold and 4-fold of those in conventional aeration, respectively. The abundance of the gene encoding nitrite oxidoreductase (nxrA) was similar in both reactors. Read taxonomy revealed that abundance of AOB-Nitrosomonas increased significantly when using micro-nano aeration, while abundance of NOB-Nitrospira abundance was similar in both reactors. The results of this study indicated that the micro-nano aeration process will increase the ammonia oxidation performance by enhancing oxygen transfer but was also shown to be beneficial for enhancing partial nitrification by specific enrichment of ammonia oxidizing bacteria. This latter result demonstrates the potential benefits of the micro-nano aeration process as an alternative approach to establishing high-rate partial nitrification.

The photochemical behavior of a model PAH, naphthalene, was investigated under simulated sunlight irradiation with different dissolved organic matter (DOM) in seawater. The results revealed that naphthalene was prone to direct photolysis (Φd = 1.34 × 10-3) and could be degraded by 3DOM*/1O2-induced reactions with fulvic acid (FA) and humic acid (HA) at low concentrations. However, the DOM at a high level dramatically decreased the kobs due to the higher light attenuation and radical competition effect. The presence of FA resulted in lower 3DOM*/1O2 generation and quantum yield compared with HA, but it achieved higher degradation kinetics due to the higher reactivity between 3FA* and naphthalene and their lower binding effect. The naphthalene degradation in natural water with different depths and DOM were modeled based on the experimental results, which revealed the important role of indirect photolysis initiated by inorganic constituents. Moreover, several degradation intermediates were identified by GC-MS and three possible pathways were proposed. The Quantitative Structure Activity Relationships (QSAR) evaluation revealed that some intermediates are more toxic than original naphthalene. This study offers further insights into the photochemical behavior of PAHs, which will facilitate our understanding of the persistence and ecological risks of organic contaminants in natural waters.

This study describes the development of an air-lift internal circulation reactor that integrates partial nitrification, anammox and denitratation (SPANADA) into a single stage bioprocess for the treatment of low C/N coal gasification wastewater. During 245 days of operation, the compartmental fluidized bed reactor achieved a total inorganic nitrogen (TIN) removal efficiency of 91.4%. Reads-based metatranscriptomic analysis found the expression of the amoA and hao genes essential for nitritation and the hzsA and hdh genes essential for anammox increased dramatically as reactor performance improved and stabilized. Another notable trend was that the total expression of the napA and narG genes, essential for denitratation, was 3-fold higher than the combined reads for nirK and nirS whose products, nitrite reductases, would lower nitrite levels reducing available substrate for anammox. Analysis of metagenome-assembled genomes revealed members of Nitrosomonas and Candidatus Brocadia, were the dominant genera of ammonium-oxidizing bacteria and anammox bacteria, respectively, and accounted for 5.5% and 10.0% of the total reads in the transcriptome. For denitratation, Thiolinea, whose only relevant gene involved in N-metabolism is narG, accounted for 8.5% of the total reads in the transcriptome and, remarkably, 84.1% of narG expression. Mass balance confirmed anammox was the dominant nitrogen removal pathway, accounting for 67.0% of the TIN removed. Nitritation and denitratation accounted for 82.7% and 17.3% of the nitrite production, respectively. The analysis reported demonstrates the development of a novel and effective one-stage nitrogen removal alternative for low C/N wastewater treatment and also helps gain insight into the underlying microbial interactions.

The acclimated, anaerobic microbial community is an efficient method for indole-containing wastewater treatment. However, our understanding of the diversity of indole-degrading communities is still limited. We investigated two anaerobic, indole-decomposing microbial communities under both denitrifying and sulfate-reducing conditions. Utilizing a near full-length 16S rRNA gene clone library, the most dominant bacteria in the denitrifying bioreactor identified was β-proteobacteria. Among these, bacteria from genera Alicycliphilus, Acaligenes and Thauera were abundant and thought responsible for indole degradation. However, in the sulfate-reducing bioreactor, Clostridia and Actinobacteria were the dominant bacterial class found and likely the main degrading species. Microbial communities in these bioreactors shared only two operational taxonomic units (OTUs). Differences in the electron acceptors of denitrification or sulfate reduction may be responsible for the higher indole removal capacity in the denitrifying bioreactor (80%) than the capacity in the sulfate-reducing bioreactor (52%). This study is the first detailed analysis of an anaerobic indole-degrading community.

Anthracene (40 mg l−1) was completely depleted by Martelella sp. strain AD-3 under 3% salinity and a pH of 9.0 after 6 days of incubation. The metabolites were extracted and identified by high-performance liquid chromatography (HPLC) retention times, mass spectrometry, 1H and 13C nuclear magnetic resonance spectrometry, and comparison to authentic compounds or literature data. On the basis of the identified metabolites, enzyme activities and the utilization of probable intermediates, anthracene degradation by strain AD-3 is proposed via two distinct routes. In route I, metabolism of anthracene is initiated by the dioxygenation at C-1,2, then proceeds through 6,7-benzocoumarin, 3-hydroxy-2-naphthoic acid, salicylic acid and gentisic acid. In route II, anthracene is metabolized to 9,10-anthraquinone. The results suggest that strain AD-3 possesses efficient anthracene biodegradability in high salinity. To our knowledge, this work presents the first report of anthracene degradation by a halophilic PAH-degrading strain via two routes. The strain AD-3 may be a useful candidate for PAH-contaminated saline-alkali soil bioremediation.

The chemical oxidation of 1,1,1-trichloroethane (TCA), a widely detected groundwater pollutant, by UV/H2O2 and UV/S2O82– processes was investigated. The effects of various factors were evaluated, including peroxide/TCA molar ratio, solution pH, Cl– and HCO3– anions, and humic acid (HA). The results showed that TCA oxidation fit to a pseudo-first-order kinetic model. The optimum H2O2/TCA molar ratio was 5:1, with TCA removal of 54.2% in 60 min. In the UV/S2O82– process, higher molar ratios (from 1/1 to 10/1) resulted in higher TCA oxidation rates, and TCA could be completely removed after 60 min with a S2O82–/TCA molar ratio of 3/1. In addition, acidic conditions were favorable for TCA removal in the UV/S2O82– process, while maximum TCA removal was observed at pH 6 in the UV/H2O2 process. Both Cl– and HCO3– anions adversely affected TCA oxidation performance, and higher concentration of HA resulted in a lag phase for TCA oxidation in both processes. Several reaction intermediates, including 1,1,1,2-tetrachloroethane, carbon tetrachloride, chloroform, tetrachloroethylene, 1,1-dichloroethylene, and tri- and dichloroacetic acids, were first identified during TCA oxidation by S2O82– chemistry, while only monochloroacetic acid was detected in the UV/H2O2 process. The results indicated that the UV/S2O82– process was much more effective than the UV/H2O2 process, but the latter was more environmentally friendly because fewer toxic intermediates were produced.