Residual status and source analysis of phthalate esters in Ulungur Lake, China.

Ulungur Lake is the largest lake in northern Xinjiang and undertakes important aquatic tasks. It is the No. 1 fishing ground in northern Xinjiang, and the problem of persistent organic pollution in the water has received much attention. However, there are few studies on phthalate esters (PAEs) in the water of Ulungur Lake. Understanding the pollution levels, distribution characteristics and sources of PAEs is of great significance for the protection and prevention of water. Fifteen sampling sites are established in Ulungur Lake to collect water samples during flood and dry periods, then seventeen PAEs are extracted from the water samples and purified by liquid-liquid extraction-solid-phase purification. Gas chromatography-mass spectrometry is used to detect the pollution levels and distribution characteristics of the 17 PAEs and analyse their sources. Results show that the concentrations of PAEs in the dry and flood periods are 0.451-9.97 µg/L and 0.0490-6.38 µg/L, respectively. The concentration of ∑PAEs with time is characterised by the dry period > the flood period. The change in flow is the main reason for the diverse concentration distributions of PAEs in different periods. The concentration of ΣPAEs in the dry period is much lower on the side near the lake entrance of the Ulungur River and Irtysh River. In the dry period, PAEs mainly come from chemical production and the use of cosmetics and personal care products; in the flood period, they mainly come from chemical production. River input and atmospheric sedimentation are the main sources of PAEs in the lake.

Seasonal variation and risk assessment of microplastics in surface water of the Manas River Basin, China.

The ubiquity of microplastics in the environment has caused great influence to ecosystems and seriously threatened human health. To better understand the variation in microplastics in different seasons in an inland freshwater environment and determine the sources of microplastic pollution and its migration features, this study investigated the characteristics of microplastic pollution during dry (April) and wet (July) seasons in surface water of the Manas River Basin, China. The size, color, shape, area distribution and compound composition of microplastics were studied. Moreover, the risk of microplastic contamination was explored based on risk assessment models. The results demonstrated that the degree of pollution caused by microplastic abundance was minor in this study area. The average abundance of microplastics in April (17 ± 4 items/L) was higher than that in July (14 ± 2 items/L). The range in the abundance of microplastics in April and July were 22 ± 5-14 ± 3 items/L and 19 ± 2-10 ± 1 items/L, respectively. Highly hazardous polymers such as Polyvinyl chloride (PVC) and Polycarbonate (PC) have a significant impact on the results of the evaluation of the presence of microplastics. This study is an important reference for understanding the characteristics of the seasonal variation in microplastics in inland freshwater environments and has practical significance, as it will allow relevant agencies to accurately assess the pollution level of microplastics in different seasons. It is of practical significance to understand the sources and sinks of microplastics in inland freshwater environment.

Amorphous Pd-Loaded Ti4O7 Electrode for Direct Anodic Destruction of Perfluorooctanoic Acid.

We here present a novel Ti4O7-based electrode loaded with amorphous Pd clusters that achieve efficient anodic destruction of perfluorooctanoic acid (PFOA), a persistent water pollutant with significant environmental and human health concerns. These amorphous Pd clusters were characterized by the disordered, noncrystalline arrangement of Pd single atoms in close proximity, in contrast to crystalline Pd nanoparticles that have been often employed to tailor the electronic properties of an electrode. We found that the Ti4O7 electrode loaded with amorphous Pd clusters significantly outperformed the Ti4O7 electrode loaded with crystalline Pd particles due to enhanced electron transfer through dominant Pd-O bonds. Combined with the efficient binding of PFOA and its degradation intermediates to the fluorinated electrode surface, this electrode was capable of mineralizing PFOA and releasing fluoride as F-. The reaction pathway was found to proceed without involving reactive oxygen species and therefore was not quenched by common anions in complex natural water systems such as chloride ions.

Efficient production and characterization of homopolymeric poly(3-hydroxyvalerate) produced by Bacillus strain PJC48.

Aliphatic polyester, poly(3-hydroxyvalerate) (PHV), is commonly produced as a granular component in bacterial cells of various species. Based on 16S rDNA gene sequence analysis, strain PJC48 was identified as a Bacillus species. The current study is aimed to screen for a high-yield strain that can produce PHV efficiently and to increase PHV product yield by optimizing the fermentative process. We identified a high-producer strain based on Nile red staining. Characterization of the PHV produced by PJC48 by nuclear magnetic resonance spectroscopy revealed that it consisted of (R)-3-hydroxyvalerate monomers. The suggested model was validated by response surface methodology. Optimization of the PHV yield resulted in an increase of 32.75% compared to control, with a maximum production of 1.64 g/L after 48 H.

Occurrence and elimination of antibiotics in three sewage treatment plants with different treatment technologies in Urumqi and Shihezi, Xinjiang.

Fourteen antibiotics, including five quinolones (QNs), five sulfonamides (SAs), and four tetracyclines (TCs), were selected to investigate their occurrence and elimination in three sewage treatment plants (STPs) by employing different treatment technologies in Urumqi (two STPs) and Shihezi (one STP), China. The STP in Shihezi was chosen as representative to investigate the distribution of antibiotics in a sludge-sewage system. Results showed that the concentrations of most detected antibiotics ranged from tens to hundreds of nanograms per liter in influent samples and under 100 ng L-1 in effluent samples. QNs and TCs were dominant species with concentrations of 2.33 mg kg-1 to 3.34 mg kg-1 and 0.36 mg kg-1 to 0.47 mg kg-1 in sludge samples, respectively. The elimination rates of target antibiotics by various STPs ranged from 17% to 100%. The STP with anaerobic/anoxic/aerobic and membrane bio-reactor technology removed antibiotics more efficiently than those with anaerobic/anoxic/oxic and oxidation ditch technology. The elimination capacities of treatment units from the three STPs were also investigated. SAs were mainly degraded in biological treatment units; conversely, QNs and TCs were significantly eliminated in sedimentary treatment units. Ozonation effectively removed remaining antibiotics but not UV and chlorination disinfection in this study.

Kinetic model for microbial growth and desulphurisation with Enterobacter sp.

Biodesulphurisation was investigated by using Enterobacter sp. D4, which can selectively desulphurise and convert dibenzothiophene into 2-hydroxybiphenyl (2-HBP). The experimental values of growth, substrate consumption and product generation were obtained at 95 % confidence level of the fitted values using three models: Hinshelwood equation, Luedeking-Piret and Luedeking-Piret-like equations. The average error values between experimental values and fitted values were less than 10 %. These kinetic models describe all the experimental data with good statistical parameters. The production of 2-HBP in Enterobacter sp. was by "coupled growth".

Distribution of antibiotic resistance genes in Bosten Lake, Xinjiang, China.

The occurrence of antibiotic resistance genes (ARGs) and resistant bacteria was quantified in 17 water samples collected across Bosten Lake, Xinjiang, China. The heterotrophic plate count method was used to detect the levels of sulfonamide- and tetracycline-resistant bacteria, which have mean concentrations of 2.50×10(5) and 4.63×10(3) CFU/mL, respectively. The resistance genes of sulfonamide (sul1, sul2) and tetracycline (tetM, tetO and tetW) were detected, and results showed that all other ARGs except the tetO gene were obtained from all samples. Four of the obtained ARGs were further quantified, and results showed that the sulfonamide resistance genes were prevalent. The relative abundance was in the range of 2.81×10(-5) to 3.33×10(-3) for the sul1/16s-rRNA and 1.04×10(-5) to 3.80×10(-3) for the sul2/16s-rRNA. For the tet genes, the relative concentrations of tetM/16s-rRNA and tetW16s-rRNA ranged from 1.18×10(-5) to 2.46×10(-4) and 1.58×10(-6) to 4.19×10(-4), respectively. The concentration divergence among ARGs may be related to the different characteristics of each gene. This study validated that Bosten Lake was affected by ARGs and resistant bacteria, thus turning the lake into an important reservoir for the transfer of ARGs and resistant bacteria.

Establishment of a modified QuEChERS extraction and liquid chromatography-tandem mass spectrometry method for multiple pesticide residues followed by determination of the residue levels and exposure assessment in livestock urine.

The establishment of an analytical method for pesticide residues in livestock urine can realize the real-time monitoring of pesticide pollution in livestock breeding. In this study, a novel method was developed for the determination of 106 pesticide residues in livestock urine based on a modified QuEChERS extraction and liquid chromatography-tandem mass spectrometry. Acetonitrile was used to extract target analytes through acidic and alkaline switching of the sample environment. The purification effect of captiva EMR-Lipid on samples was investigated. Three kinds of materials, C18, polar enhanced polymer (PEP), N-propylethylenediamine (PSA), were selected from 20 kinds of materials as adsorbents for QuEChERS. A mass analysis was carried out using simultaneous scanning in both positive and negative ion mode and multiple reaction monitoring mode. All analytes showed good linearity, with correlation coefficients (R2) greater than 0.9923; their limits of quantification were 0.02-1.95 ng/mL. The average recoveries at low, medium, and high spiked levels were in the range of 70.1 %-117.3 %, with intra-day precision ranging from 3.4 % to 16.9 % and inter-day precision ranging from 4.0 % to 19.3 %. The established analytical method was used to analyze the pesticide residue in swine urine and bovine urine collected from farms in Yining, Xinjiang, China. A total of 8 pesticides were detected, and the residue ranged from less than the limit of quantitation to 22.4 ng/mL. The top three pesticides with the highest detection frequency were clothianidin, thiamethoxam, and dinotefuran. The exposure assessment based on the monitored pesticide residue concentration levels showed that the detected pesticides could pose little risk to cattle and pigs.

Bioaugmented biological contact oxidation reactor for treating simulated textile dyeing wastewater.

In this study, modified polyamide fibers were used as biocarriers to enrich dense biofilms in a multi-stage biological contact oxidation reactor (MBCOR) in which partitioned wastewater treatment zone (WTZ) and bioaugmentation zone (BAZ) were established to enhance the removal of methyl orange (MO) and its metabolites while minimizing sludge yields. WTZ exhibited high biomass loading capacity (5.75 ± 0.31 g/g filler), achieving MO removal rate ranging from 68 % to 86 % under different aeration condition within 8 h in which the most dominant genus Chlorobium played an important role. In the BAZ, Pseudoxanthomonas was the dominant genus while carbon starvation stimulated the enrichment of chemoheterotrophy and aerobic_chemoheterotrophy genes thereby enhanced the microbial utilization of cell-released substrates, MO as well as its metabolic intermediates. These results revealed the mechanism bioaugmentation on MBCOR in effectively eliminating both MO and its metabolites.

Optimization, validation, and application of a liquid chromatography-tandem mass spectrometry method for the determination of 47 banned drug and related chemical residues in livestock urine using graphitized carboxyl multi-walled carbon nanotubes-based QuEChERS extraction.

The establishment of an efficient method for the analysis of drug residues in animal urine facilitates the real-time monitoring of drugs used in the production of animal-derived food. A modified QuEChERS extraction-liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established for the determination of 47 banned drug and related chemical residues in livestock urine. The sample was extracted with acetonitrile by converting the acid-base environment. The sample cleanup effects of seven solid phase extraction cartridges and two EMR-Lipid products were compared, and three materials, including graphitized carboxyl multi-walled carbon nanotubes (MWCNTs), PSA, and C18, were selected as QuEChERS adsorbents from 24 materials. All analytes showed good linearity, with correlation coefficients (R2) greater than 0.9936. Low limits of quantification could be obtained, ranging from 0.2 to 5.5 ng/mL. The average recoveries at low, medium, and high spiked levels were in the range of 70.8-114.9 %, with intra-day precision ranging from 2.4 % to 11.2 % and inter-day precision ranging from 4.5 % to 16.1 %. Swine urine and bovine urine samples collected from different farms were effectively analyzed using the developed method, and metronidazole was detected in three swine urine samples.

Management of biofilm by an innovative layer-structured membrane for membrane biofilm reactor (MBfR) to efficient methane oxidation coupled to denitrification (AME-D).

Aerobic methane oxidation coupled with denitrification (AME-D) has garnered significant attention as a promising technology for nitrogen removal from water. Effective biofilm management on the membrane surface is essential to enhance the efficiency of nitrate removal in AME-D systems. In this study, we introduce a novel and scalable layer-structured membrane (LSM) developed using a meticulously designed polyurethane sponge. The application of the LSM in advanced biofilm management for AME-D resulted in a substantial enhancement of denitrification performance. Our experimental results demonstrated remarkable improvements in nitrate-removal flux (92.8 mmol-N m-2 d-1) and methane-oxidation rate (325.6 mmol m-2 d-1) when using an LSM in a membrane biofilm reactor (L-MBfR) compared with a conventional membrane reactor (C-MBfR). The l-MBfR exhibited 12.4-, 6.8- and 3.4-fold increases in nitrate-removal rate, biomass-retention capacity, and methane-oxidation rate, respectively, relative to the control C-MBfR. Notably, the l-MBfR demonstrated a 3.5-fold higher abundance of denitrifying bacteria, including Xanthomonadaceae, Rhodocyclaceae, and Methylophilaceae. In addition, the denitrification-related enzyme activity was twice as high in the l-MBfR than in the C-MBfR. These findings underscore the LSM's ability to create anoxic/anaerobic microenvironments conducive to biofilm formation and denitrification. Furthermore, the LSM exhibited a unique advantage in shaping microbial community structures and facilitating cross-feeding interactions between denitrifying bacteria and aerobic methanotrophs. The results of this study hold great promise for advancing the application of MBfRs in achieving efficient and reliable nitrate removal through the AME-D pathway, facilitated by effective biofilm management.

Distribution of sterols and the sources of pollution in surface sediments of Ulungur lake, Xinjiang.

Domestic sewage discharged into lakes brings great pressure to the ecological environment. This study selected sediment from an inland lake as a research object to evaluate pollution of the environment. Eight sterols were used to evaluate the content of pollutants, while the ratios of sterols were used as the index to analyze the sources of pollution. The correlations were analyzed between sterols and total organic carbon (TOC), salinity and particle size. The distribution and composition of sterol compounds were determined in 12 surface sediment samples collected from Ulungur lake. The total concentrations of detected sterols in the sediments ranged from 1.3 to 36.3 µg/g.dw. The most abundant sterol detected was ß-sitosterol (STI) with average concentrations of 2.6 µg/g.dw, followed by cholesterol (CHOE), stigmasterol (STIG) and stigmastanol (STAN). The concentration of coprostanol (COP) was between 0.03 and 1.66 µg/g.dw. Through correlation analysis, it was found that there was a significant correlation between fecal sterols and plant sterols. So the plant sterols shall not be neglected in evaluating the sources of pollution for their impact to identify the fecal sources. The study suggests that the composition and distribution of sterols in surface sediment provide useful information for environmental contamination monitoring and assessment in the inland lake.

In five wastewater treatment plants in Xinjiang, China: Removal processes for illicit drugs, their occurrence in receiving river waters, and ecological risk assessment.

Residues of illicit drugs are frequently detected in wastewater, but data on their removal efficiency by wastewater treatment plants (WWTPs) and the ecological risks to the aquatic environment are lacking in this study. The research evaluates the residues, mass load, drug removal efficiency, and risk assessment of illicit drugs in WWTPs and aquatic environments (lakes) in Xinjiang, China. Initially, the concentration (incidence) and mass load of 10 selected illicit drugs were analyzed through wastewater analysis. The detected substances included methamphetamine (METH), morphine (MOR), 3,4-methylenedioxy methamphetamine (MDMA), methadone (MTD), cocaine (COC), benzoylecgonine (BE), ketamine (KET), and codeine (COD), with concentrations ranging from 0.11 ± 0.01 ng/L (methadone) to 48.26 ± 25.05 ng/L (morphine). Notably, morphine (59.74 ± 5.82 g/day) and methamphetamine (41.81 ± 4.91 g/day) contributed significantly to the WWTPs. Next, the drug removal efficiency by different sewage treatment processes was ranked as follows: Anaerobic-Oxic (A/O) combined Membrane Bio-Reactor (MBR) treatment process > Oxidation ditch treatment process > Anaerobic-Anoxic-Oxic (A2/O) treatment process > Anaerobic-Anoxic-Oxic combined Membrane Bio-Reactor treatment process. Finally, the research reviewed the concentration and toxicity assessments of these substances in the aquatic environment (lakes). The results indicated that Lake1 presented a medium risk level concerning the impact of illicit drugs on the aquatic environment, whereas the other lakes exhibited a low risk level. As a result, it is recommended to conduct long-term monitoring and source analysis of illicit drugs, specifically in Lake1, for further investigation. In conclusion, to enhance the understanding of the effects of illicit drugs on the environment, future research should expand the list of target analytes.

Differences in microbial community composition and factors affecting different particulate matter during autumn in three cities of Xinjiang, China.

Environmental pollution has become an issue of increasing concern in China, owing to the country's rapid economic development. Atmospheric particulate matter (PM) is known to be an important parameter in air quality monitoring; further, bioaerosol forms a crucial component of PM. As the climatic environments in the north and south of Xinjiang, China, are significantly different, here, atmospheric PM samples collected from three cities, Shihezi, Yining, and Tumushuk, located in different directions, were analysed for a better understanding of the spatial distribution patterns of microbial community composition of Xinjiang. The16s rDNA and 18 s rDNA were used to locate bacteria and fungi in PM2.5, PM10, and total suspended particulate matter (TSP) at the species level and genus level, and the microbial communities with the top 15 abundances were selected for analysis. The reports indicate that the most abundant group in Shihezi and Yining was Cenchrus_americanus, which belongs to Proteobacteria. The remaining 14 dominant species had their own distribution pattern in each city. The most dominant strain in Tumushuk was Bacillus_taeanensis, but this strain was not detected in Yining and Shihezi. Similarly, the most predominant fungus in Tumushuk (Microdorylaimus_miser under Myriophyllum) was not detected in the other two cities. The analysis of the effect of environmental impact factors on bacteria and fungi revealed that the impact factors such as temperature, humidity, and wind speed had a greater effect on microorganisms, while O3 had a negative correlation with most microorganisms, owing to its toxicity. Overall, the results of this study show that short-range transported air masses have a greater impact on local pollutants and microorganisms.

Analysis, occurrence, and consumption of substances with abuse potential in Xinjiang, China, from 2021 to 2022.

Understanding the consumption patterns of substances with abuse potential in the population is critical in combating drug crimes in the region. In recent years, wastewater-based drug monitoring has become a complementary tool worldwide. This study aimed to use this approach to understand the long-term consumption patterns of abuse potential substances in Xinjiang, China (2021-2022) and to provide more detailed and practical information on the current system. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed to quantify the levels of abuse potential substances in wastewater. Subsequently, the detection rate and contribution rate of the drug concentrations were evaluated through analysis. Eleven of abuse potential substances were detected in this study. The influent concentrations ranged from (0.48 ng/L) to 133.41 ng/L, with dextrorphan having the highest concentration. The highest detection frequency rates were for morphine (82 %), dextrorphan (59 %), 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (43 %), methamphetamine (36 %), and tramadol (24 %). According to a study on wastewater treatment plants (WWTPs) removal efficiency, compared to the total removal efficiency in 2021, the total removal efficiency of WWTP1, WWTP3, and WWTP4 increased in 2022, while WWTP2 decreased slightly, and WWTP5 did not change significantly. Upon examination of the use of 18 selected analytes, it was determined that methadone, 3,4-methylenedioxy methamphetamine, ketamine, and cocaine were the primary substances of abuse in the Xinjiang region. This study identified significant abuse substances in Xinjiang and identified research priorities. Future studies should consider expanding the study site to obtain a comprehensive understanding of the consumption patterns of these substances in Xinjiang.

Content level and risk assessment of phthalate esters in surface water of Bosten Lake, China.

Bosten Lake is the main fishing and grazing area in Xinjiang. The pollution of phthalate esters (PAEs) in water has attracted much attention, but limited research has been conducted on PAEs in Bosten Lake. The distribution of PAEs in fifteen sampling sites of surface water in the dry and flood seasons were investigated to explore the content level of PAEs in Bosten Lake, and the risk was evaluated. Seventeen PAEs were detected by GC-MS after liquid-liquid and solid-phase purification. Results showed that the content of ∑PAEs in the water during dry and flood seasons is ND-26.226 µg/L and ND-7.179 µg/L. The content of PAEs in the water of Bosten Lake is at a medium level. DBP and DIBP are the main PAEs. The content of PAEs is related to the physicochemical properties of water, and the physicochemical properties of water in dry season have a more serious impact on PAEs. PAEs in water mainly come from domestic pollution and chemical production. The results of health risk assessment indicate that PAEs in water do not pose a carcinogenic risk or a non carcinogenic risk to human, which can meet the conditions of Bosten Lake as a fishing ground and livestock base, but the pollution of PAEs cannot be ignored.

Characterization of rhizobacterial strain Rs-2 with ACC deaminase activity and its performance in promoting cotton growth under salinity stress.

A plant growth-promoting rhizobacterial strain Rs-2 with 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity was isolated from salinized soils using ACC as the sole nitrogen source. Based on its physiological and biochemical properties and 16S rDNA sequence analysis, this strain was identified as Raoultella planticola. The maximum value of nitrogen fixation, dissolved phosphorus and dissolved potassium of Rs-2 were 148.8 µg/ml, 205.0 and 4.31 mg/l, respectively within 192 h liquid culture. The germination rate of cotton seeds (Gossypium hirsutum L.) inoculated with Rs-2 (Rs-2-S) was enhanced by 29.5 % in pot experiments compared with that of the control (CK-S). Subsequently, individual plant height, fresh weight and dry weight of cotton seedlings in Rs-2-S treatment increased by 15.0, 33.7 and 33.3 %, respectively, compared with those in CK-S treatment. Statistical analysis showed that the inoculums of Rs-2 promoted significantly (P < 0.05) cotton growth. Further analysis showed that Rs-2 reduced the quantities of ethylene and abscisic acid in cotton seedlings, and increased indole acetic acid content in cotton seedlings under salinity stress. The accumulation of N, P, K(+), Ca(2+) and Fe(2+) in the cotton plants was increased significantly (P < 0.05) in Rs-2-S treatment, whereas the uptake of Na(+) in cotton seedlings decreased (P < 0.05). Hence, the present observations suggested that R. planticola Rs-2 could have a promising potential for promoting cotton growth and alleviating salinity stress.

Enhanced visible-light-driven photocatalytic degradation of tetracycline by 16% Er3+-Bi2WO6 photocatalyst.

The widespread use of antibiotics in drug therapy and agriculture has seriously polluted the aquatic environment. Bismuth tungstate (Bi2WO6) is a new and efficient visible-light catalyst that is simple to prepare, non-toxic, stable, and corrosion resistant. Nonetheless, its efficiency has remained limited, and erbium (Er) mixing has been tested to address this. Here, a new Er3+-mixed Bi2WO6 photocatalyst was successfully prepared through the one-step hydrothermal method; pigments were characterized via XRD, SEM, BET, XPS, Uv-vis, PL and EIS. The results showed that the 16% Er3+-Bi2WO6 photocatalyst is a 250 nm flower-like nanosheet with a specific surface area of 67.1 m2/g and bandgap (Eg) of 2.35 eV, which provides the basis for superior performance. When the concentration of the catalyst was 0.4 g/L, 94.58% of the tetracycline (TC) solution (initial concentration of 10 mg/L) degraded within 60 min under visible light irradiation (λ ≥ 420 nm). ESR and LC-MS were used to identify the free radicals and intermediates for the degradation of TC pollutants; a photocatalytic degradation system and pathway were proposed. This solar-driven system will ultimately reduce resource consumption, providing a sustainable and energy-saving environmental decontamination strategy.

Understanding of the Dual Roles of Phosphorus in Atomically Distributed Fe/Co-N4P2 over Carbon Nitride for Photocatalytic Debromination from Tetrabromobisphenol A.

Atomically dispersed Fe and Co on carbon nitride under an external phosphine (PH3) atmosphere (P-Fe1Co1/CN) are prepared. Combined with the results of calculations and experiments, the formed P-induced bimetallic single atoms of Fe/Co-N4P2 can provide more reactive sites to enhance optical performance. Meanwhile, the introduced P can coordinate with Fe and Co and change the sole nitrogen coordination environment via the bridging effect. Herein, on the one hand, the structure of Fe-P-Co enhances interactions of single atoms in heterogeneous metals, and, on the other hand, the formed Fe/Co-N4P2 effectively changes the electron configuration in coordination centers. All of the abovementioned findings can enhance the photocatalytic performance of P-Fe1Co1/CN, achieving 96% removal and 51% debromination rates from tetrabromobisphenol A under visible light irradiation. The two efficiencies can be further improved under UV-vis light irradiation. The findings of this work reveal the dual roles of P in bimetallic single-atom catalysts, provide a facile method to synthesize P-assisted bimetal single-atom photocatalysts, and highlight the great potential of carbon nitride-based single atoms as photocatalysts.

Formation of stable imine intermediates in the coexistence of sulfamethoxazole and humic acid by electrochemical oxidation.

The electrochemical degradation performance of sulfamethoxazole (SMX) was studied in the presence of humic acid (HA) by using a Ti/Ti4O7/ß-PbO2 anode. The electrochemical degradation efficiency of SMX decreased from 93.4% to 45.8% in 50 min after the addition of 25 mg L-1 HA. The pseudo-first-order kinetic rate constant decreased by 71.4%, and the EEO value increased from 63.8 Wh L-1 to 90.9 Wh L-1. HA and its degradation intermediates could compete for free radicals, especially for ·OH, with SMX. The analytical results obtained using UPLC-ESI-Q-TOF-MS showed that 18 degradation intermediates were identified in the coexistence of SMX and HA. Four imine intermediates were formed through the reactions between the aniline moieties of SMX and quinone groups in the HA structure through covalent bonds. Furthermore, the relative abundances of the intermediates demonstrated that the imine intermediates were complex and stable during electrochemical degradation.