In order to explore the resistance mechanism of polymer ultrafiltration membranes to ozone, polyvinyl chloride（PVC）membranes and polyvinylidene fluoride（PVDF）membranes as representatives were used, and systematically evaluated the effects of ozone on the water permeability, pollutant retention capacity and mechanical properties of the membranes by simulating 0.1mg/L ozone exposure for 0.5 years, and analyzed the changes in chemical properties. The results showed that the water permeability of the PVC membrane significantly increased under the action of ozone for 36 hours, up to more than 4times that of the new membrane, while the retention capacity of humic acid（HA）decreased by about 27.6%. The water permeability and retention performance continued to decrease with the extension of exposure time. The water permeability of PVDF membranes increased significantly in the initial stage, with the HA retention performance decreasing by about 40.2% after 36hours of aging. However, the performance tended to stabilize after 1 hour of aging. Ozone aging led to a decrease in the hydrophilicity of the two membranes, but the hydrophilicity of PVC membranes decreased to a lesser extent, showing their relative advantages in maintaining hydrophilic properties. The analysis of the membrane structure mechanism showed that ozone mainly damaged the membrane performance through oxidation and the loss of the hydrophilic additive polyvinyl pyrrolidone（PVP）, and the membrane matrix itself remained intact, which was also confirmed by SEM observations. The mechanical properties of the two membranes decreased after aging, but the PVDF membrane showed relatively high mechanical strength. A comprehensive comparison of the ozone resistance of PVC, and PVDF, showed that PVC had relative advantages in ozone aging resistance in terms of retention, anti-pollution, hydrophilic, and mechanical properties, followed by PVDF. These findings provide an experimental basis and theoretical reference for the application and optimization of polymer ultrafiltration membranes in ozone-containing water treatment environment.

In order to further supplement the mechanism of the enhanced coagulation efficiency of the fine bubble co-coagulation process and the potential of the process for engineering applications, this paper investigated the effect of calcium ion concentration response on the enhanced removal of humic acid（HA）by the fine bubble co-coagulation process. The results showed that the fine bubbles could enhance the removal of HA with different calcium ion concentration responses, but the enhancement effect was different with different circulation times. When the cycle time of fine bubbles was kept constant at 1min, the participation of fine bubbles in the coagulation process could enhance the removal efficiency of HA by forcing the hydrolysis of polyaluminum chloride（PACl）, elevating the potential of the solution to the isoelectric potential, and promoting the complexation between HA and Ca²⁺, and the removal efficiency of HA increased with the increase of Ca²⁺ concentration, and the removal efficiency of HA increased about 42% with the increase of Ca²⁺ concentration, and increased about 42% with the increase of Ca²⁺ concentration, and increased about 42% with the increase of Ca²⁺ concentration. The HA removal efficiency increased with increasing Ca²⁺ concentration, up to about 42% compared to the conventional coagulation process without the presence of fine bubbles. In addition, with the extension of the fine bubbles circulation time, the Zeta potential of the solution gradually increased, which affected the enhanced removal efficiency of HA. The above findings provide data and theoretical support for the application of the fine bubble co-coagulation process in engineering practice.

The advanced oxidation technology of persulfate（PDS）activation by CuO have been hotly sought as one of the effective strategies for degrading organic pollutants in water. However, there are still certain issues such as the low efficiency of PDS activation, the small specific surface area of CuO, and the low conversion efficiency of Cu（II）/Cu（I）. Herein, the flake copper oxide（CCB-300）with high activity and large specific surface area（32.8m²/g）was successfully synthesized through a two-step hydrothermal-calcination method. Multiple characterization analysis, such as X-ray powder diffractometry（XRD）, N₂ adsorption-desorption analysis, Scanning electron microscopy（SEM）, Transmission electron microscopy（TEM）and X-ray photoelectron spectroscopy（XPS）, were utilized to analyze crystal structure, morphology and element composition of CCB-300. Furthermore, the performance of the CCB-300 for degradation of tetracycline（TC）via peroxydisulfate activation under visible light（Vis）was investigated. The findings revealed that the TC removal rate reached 96.9% within 60minutes under the circumstances of 0.05g/L CCB-300, 0.5mmol/L PDS, 50mg/L TC and unadjusted initial pH. Electron paramagnetic resonance spectroscopy（EPR）and radical quenching experiments indicated that both ¹O₂ produced by the non-radical pathways and and ⋅OH generated via the radical pathways were involved in the degradation reaction. Ultraviolet-visible diffuse reflectance spectroscopy and photoelectrochemical tests confirmed that CCB-300 exhibited excellent visible light absorption capacity and charge transfer performance. The photogenerated electrons excited by visible light accelerate the redox cycle of Cu（II）/Cu（I）, facilitating the conversion of PDS to and ⋅OH, and further enhancing the efficiency of TC degradation. The repeatable experiments demonstrated that CCB-300exhibited favorable reusability and stability. Finally, the possible reaction mechanism was proposed. This study provided a novel method for tetracycline degradation through synergistic persulfate activation by visible light and heterogeneous catalysts.

To deal with problems such as high concentration of arsenic（As）and fluorine（F）in water, along with difficulty in dealing with complex pollution and irrigation utilization, zirconium-aluminum modified biochars were synthesized to study their adsorption efficiency and mechanism of As and F. The study was conducted to explore the impact of initial concentration, adsorption time, pH, and co-existing ions on their adsorption. The combination of SEM, BET, FTIR, and X-ray techniques were applied to characterize and analyze the materials. The results showed that zirconium-aluminum bimetallic modified biochar（ZA-BC）was an excellent mesoporous biochar with a good pore structure, which can rapidly adsorb As and F ions within 6hours. With initial concentrations of 1mg/L for As and 5mg/L for F, and a biochar dosage of 1g/L, As and F removal rates can reach 98.7% and 95.2%. The optimal adsorption pH of As and F by ZA-BC was 4~5, the zero charge point of the material was 9.1. Its adsorption fits the Langmuir isotherm and pseudo-second-order kinetic models within a pH range of 4.0~9.1. ZA-BC adsorbed As and F at 19.62 and 28.70mg/g, respectively, with CO₃^2- most affecting its efficiency. ZA-BC's adsorption of As involved electrostatic attraction and surface complexation, whereas for F, it's primarily electrostatic and ion exchange. The hydroxyl group was vital for adsorption, with metal modifications enhancing the immobilization of As and F via M-OH groups. Comprehensive tests had shown that ZA-BC was a promising adsorbent for removing arsenic and fluoride from water.

Using florfenicol（FFC）as the target pollutant, schwertmannite and jarosite as catalysts synthesized by the mediation of A.ferrooxidans to investigate their effectiveness in catalyzing Fenton-like reactions for FFC degradation. Initially, the two minerals were characterized using SEM, XRD, FTIR and BET analysis. Subsequently, the impact of four key variables—mineral dosage,H₂O₂ concentration, pH, and temperature—on FFC degradation was studied. Finally, the degradation mechanism of FFC and the reusability of the minerals were analyzed. The results indicated that the biosynthesized schwertmannite and jarosite were pure minerals, with average particle diameters of approximately 2.5µm and 5.0µm and jarosite exhibiting more noticeable aggregation. The specific surface areas of schwertmannite and jarosite were 116.67m²/g and 87.52m²/g, respectively, with total pore volumes of 0.098cm³/g and 0.065cm³/g and average pore diameters of 2.986nm and 2.867nm. Increasing the mineral dosage enhanced the degradation efficiency of FFC by both minerals. The degradation efficiency of FFC initially increased and then decreased with an increase in the H₂O₂ concentration. Under acidic conditions, both minerals exhibited better degradation effects. The degradation rate increased with rising temperature. Under the combined experimental conditions of a mineral dosage of 10g/L, an H₂O₂ concentration of 200mg/L, an pH of 3.00, and a temperature of 36℃, combined with Liquid Chromatography-Mass Spectrometry（LC-MS）test results, the degradation mechanism of FFC by the two minerals was inferred as follows: The minerals adsorbed H₂O₂ onto their surfaces, catalyzing its decomposition to produce hydroxyl radicals（·OH）, which oxidized FFC into intermediate products, ultimately leading to inorganic substances. A total of six intermediate products were detected during the Fenton-like reaction, including small organic molecules such as alcohols, aldehydes, or carboxylic acids containing benzene rings, amide groups, or amine groups, as well as methyl phenyl sulfone. After 10cycles of reuse, the crystal structure and functional groups of the two minerals remained unchanged, demonstrating good stability.

In view of the accumulation of nitrite in the effluent of denitrification biofilter in water recycling plant, nitrite accumulation in denitrification filter units of 4recycled water plants was investigated. Two denitrification filter process units of recycled water plant, G（with nitrite accumulation）and W（without nitrite accumulation）, were selected as research objects to explore the causes of nitrite accumulation under the condition of low carbon to nitrogen ratio influent. The results showed that operating parameters such as backwashing cycle and mode of filter had little effect on nitrite accumulation. The sludge denitrification rates of plants G and W were 0.51 and 0.92 mgNO₃/（mgVSS·d）, respectively. The accumulation of nitrite in the effluent from the filter of Plant G was due to the weak denitrification ability of microorganisms in the filter. When nitrate nitrogen was present in the denitrification process, the denitrification rate of nitrite in the sludge of Plant G was 75% lower than that of plant W, and it was easier to produce nitrite accumulation. When the sludge biomass of Plant G was increased to twice the concentration of plant W, the maximum nitrite denitrification rate still couldn’t reach the level of plant W, so the biomass was not the main reason for the accumulation of nitrite in Plant G. The results of microbial community structure analysis showed that the abundance of Methylotenera in the filter of W plant was 12.9% higher than that of G plant. The denitrification process was mainly completed by denitrifying bacteria using methyl type nutrition, which was the cause of nitrite accumulation happening or not, and it was not necessary to consider the influence of bacteria species using other organic types on nitrite accumulation.

The effects of the formation of iron minerals at the interface of birnessite（MnO₂）on the environmental behavior of antimony（Sb）were systematically studied in this paper. Many nanoparticles and abundant pore structure was found on the obtained Fe-Mn binary oxide（Fe-MnO₂）. HRTEM and XRD analysis indicated that the nanoparticles anchored on MnO₂ was ferrihydrite. The iron minerals formed on MnO₂ enhanced adsorption performance for Sb（III）and Sb（V）. The adsorption capacities of Sb（III）and Sb（V）by Fe-MnO₂ were 397.4 and 247.7mg/g, respectively, which was much higher than that of MnO₂ for Sb（III）and Sb（V）immobilization（342.0 and 71.8mg/g）. The chemical bond complexation was the dominant mechanism for Sb（III）and Sb（V）immobilization. The electrostatic adsorption played an important role in Sb（V）immobilization. The ferrihydrite made a significant contribution for reducing the mobility of Sb. MnO₂ played the critical role in the transformation of Sb（III）to Sb（V）. This study not only reveals the formation mechanism of Fe-Mn binary oxide, but also helps to further understand the migration and transformation behavior of Sb in the environment.

This paper optimized the traditional comprehensive water quality identification index model（CWQI）and established two improved models: the improved comprehensive water quality identification index model based on game theory（ICWQI_G）, which considered both subjective weight and objective weight, and the improved comprehensive water quality identification index model with phased period combination weights（ICWQI_P）, which incorporated the variation of weight time. Taking Qionghai Lake as a case, the water quality monitoring data of 11 sampling sites in different hydrological periods from 2020 to 2023 were selected to evaluate the water quality of Qionghai Lake using ICWQI_G and ICWQI_P models, which could verify the scientific validity of the improved comprehensive water quality identification index method. The results show that, compared with the traditional CWQI model, the improved ICWQI_G and ICWQI_P models both take into account the factor of TP exceedance. The evaluation results could better reflect the actual water quality of the study area, and sensitively identify more pollution risk areas and severely polluted water bodies.ICWQI_P used phased weights instead of uniform weights, compensating the effect of environmental factors such as such as precipitation on the weight of water quality. This could better identify the key environmental variables affecting water quality in different periods, leading to more accurate and reasonable results. At the same time, based on the improved comprehensive water quality identification index method, it was found that the water quality of Qionghai Lake in 2023 was worse than that in 2020~2022. The pollution degree of the northwestern lake area was higher than that in the eastern and southern lake area. The improved ICWQI_G and ICWQI_P models showed better rationality in the water quality assessment of the Qionghai Lake, providing theoretical support for the refined management of the lake’s ecological environment, and offering important reference value for water quality assessment of other similar water bodies.

The study utilized filter mud and bagasse as raw materials for the co-hydrothermal carbonization process at 240℃-60min-5:1. The primary objective of this study was to investigate the impact of liquid-phase cycling on the solid-liquid phase products of the co-hydrothermal carbonization process and to elucidate the reaction pathways. The experimental findings demonstrated that liquid-phase cycling significantly enhanced the reaction process of co-hydrothermal carbonization, resulting in substantial improvements in the hydrochar properties. In the liquid-phase cycling process, there was a substantial increase in the hydrochar yield and higher heating value（HHV）, accompanied by a significant decrease in ash content and an increase in microsphere structures on the surface. Following the second cycling, the hydrochar obtained a maximum specific surface area of 31.2m²/g, and the contents of the groups CHX, C-C/C=C, and -C/OR/-C-NR exhibited a tendency to increase, while the contents of C=O/C=N and -COOR decreased significantly; In the liquid-phase products, the contents of organic acids and ketones increased. Concurrently, the proportion of aromatic compounds remarkably rose from 0.31% to 13.75%, and hydrocarbons, amides, and esters decreased. Within the liquid-phase cycle, the acidic environment generated by the accumulation of organic acids served as a catalyst for hydrolysis and other reactions, and simultaneously facilitated the Maillard reaction, which effectively enhanced the degree of aromatization of the hydrochar. Moreover, it was beneficial for fortifying the oxygen-containing functional groups on the surface of the hydrothermal carbon, thereby creating more chemically active sites. Consequently, the hydrochar was bestowed with enhanced adsorption capabilities and its potential for land application was elevated.

To investigate the feasibility of anaerobic digestion of antibiotic fermentation residues（AFR）as sole substrates, several typical AFR, including erythromycin fermentation residue（EFR）, cephalosporin fermentation residue（CFR）, and penicillin fermentation residue（PFR）were chosen as raw materials for digestion in this study. Batch assays of methane production potential and kinetics experiments were conducted at mesophilic temperature（35±1℃）to explore the basic characteristics of anaerobic digestion of different AFR. Mass balance and correlations between basic characteristics of raw materials and digestion performance were compared and contrasted. Results showed that EFR had the highest methane production potential, approximately 226mL/g VS, which was 27.0% and 20.2% higher than CFR and PFR, respectively. Distinct kinetic characteristics and metabolic activity differences were exhibited by different antibiotic fermentation residues during anaerobic fermentation. The highest biogas production rate, which was 13.2mL/（g VS·d）, was found in PFR. A clear two-stage characteristic was exhibited by EFR, with the first-order kinetic constants K₁ and K₂ being 0.0336 and 0.2012d^-1, respectively. Material balance verification confirmed the reliability of the experimental results, and the remaining insoluble substances significantly impact the startup and stability of the anaerobic system. Correlation analysis indicated that the parameters of SCOD/TCOD, C/N, protein, and fat content in the fermentation residues are important for assessing their performance in anaerobic fermentation, suggesting that optimizing the characteristics of the fermentation residues can improve fermentation efficiency. It was demonstrated that antibiotic fermentation residues treated with antibiotic removal can serve as a single substrate for anaerobic fermentation, providing a new solution for the resource utilization of fermentation residues.