In this study, GCW was coupled with the advanced oxidation system based on Fe²⁺ activated O₂ to achieve efficient transmission and uniform distribution of chemical agents while continuously replenishment of oxygen to groundwater, so as to enhance the remediation effect of the Fe²⁺/O₂/ligand was advanced oxidation system. The variation law of groundwater flow field and enhanced transport effect of solute under the enhancement of GCW were clarified using two-dimensional simulation tank experiment combined with visualization methods such as tracer dyeing. In addition, sodium tripolyphosphate (STPP) was selected as the ligand, and the effect of advanced oxidation system on the remediation of p-nitrophenol (PNP) polluted aquifer was investigated by injection of chemicals into the well. The results show that GCW had achieved efficient transmission of chemical agents and provided sufficient O₂ for advanced oxidation reactions. Under the enhancement of GCW, PNP was degraded throughout the simulated tank, with an average degradation rate of 62% in 15h. The results provide a new insight for efficient remediation of organic contaminated groundwater.

In order to explore the characteristics and influencing factors of nitrogen export at the watershed scale during storm events, this study carried out water quality and quantity monitoring of six typical storm events in the Fengyu River Watershed in the upper subbasin of Erhai Lake in Basin 2022 and 2023. The changes of nitrogen export during rainfall-runoff process and the influence mechanism of rainfall intensity, duration, flow and other factors on nitrogen load were investigated. The results indicated that it was more likely to cause larger rainfall runoff when the antecedent soil moisture was highter in the early stage of rainfall event. A large fluctuation of nitrogen concentration was observed when the rainfall intensity reached heavy rain (level 3), indicating that the loss of nitrogen is affected by the rainfall intensity. The analysis of different stages of rainfall events showed that nitrogen was mainly lost in the late stage of the event, accounting for about 62.25%~78.77% of nitrogen load during the whole event, but the amount of nitrogen loss per unit time was large in the early stage of rainfall. For heavy and extreme events, the proportion of nitrogen loss in the middle period was more than 50% of nitrogen load during the whole event, and the nitrogen loss per unit time was the largest in the middle period of the event. Redundancy analysis of rainfall-runoff process and nitrogen loss factors showed that nitrogen concentration change and load export were mainly positively correlated with Antecedent Precipitation Index (API), followed by average rainfall intensity (RI), maximum 30-minute rainfall (I30) and peak flow (FP). Among them, ammonia nitrogen (NH₄⁺-N) and nitrate nitrogen (NO₃^--N) were significantly correlated with total discharge (FA), duration of rainfall (RT), and total rainfall (RA). However, dissolved organic nitrogen (DON) has a greater correlation with API and a weaker or negative correlation with other factors.

Water-soluble polyvinyl alcohol nanofibers were utilized as the adhesive layer, and a steam atomization method was employed as a substitute for high-temperature treatment to fabricate PET/PPS nanofiber membrane composite filters through a circular roller stretching and pressing technique. The performance of the composite filters was characterized. The results indicated that the adhesion strength of the PET/PPS nanofiber membrane composite filter reached a maximum of 4.521N when the pressure was set at 0.436N/cm², the PVA spinning amount was 42.857mL/m², and the processing temperature during the pressurization was maintained at 20℃. The filtration efficiency for fine particulate matter with a diameter of 0.3µm achieved 98.86%. In dynamic filtration performance tests, after 30 cycles of constant pressure blowing, the time required for a single cycle was recorded as 13.5minutes, with a residual resistance of 265.4Pa, which outperformed existing PTFE-coated filter materials.

This study was aimed to rapidly remediate the cracked contaminant containment and carrying structure (3C structure) and carrying structure by composite contaminant containment and carrying structure (4C structure) in operating plant. To assess the effectiveness of the 4C structure, both field and laboratory tests were performed. Field tests included elevation monitoring, rebound modulus testing, and volatile organic compounds (VOCs) concentration detection, while laboratory tests focused on determining the compressive strength and permeability coefficient of the core samples. The results indicated that the injected polymers exert a compressive force on the surface layer of 4C structure, which reduces the elevation variance by 71.4%, thereby markedly enhancing its flatness. Additionally, regarding the 14 filed test points on the surface layer with an average crack width of 7.5mm, the rebound modulus (E) values at 42.9% of these test points achieved over 80% of E value measured within the uncracked control area. The axial compressive strength of core samples from these points increased by 0.38 times, and the penetration resistance of the base soil layer increased by 21.3%. These results suggested a significant improvement in the load-carrying performance of 4C structure compared with the cracked 3C structure. Furthermore, the permeability coefficient of the core samples was reduced by approximately 2orders of magnitude, and the VOCs concentration in the sampling holes decreased by 80%. This demonstrated the contaminant containment performance of 4C structure was also significantly improved. This research provided an innovative method to assess and improve the service performance of cracked contaminant containment and carrying structure in operating plant.

The persulfate-based advanced oxidation technology for antibiotic-containing wastewater treatment has become a current research hotspot in water treatment. Carbon-based materials have been used as green materials for activating persulfate due to their chemical stability and absence of secondary pollution. However, the catalytic activity of undoped or modified carbon materials is limited. This paper reviews strategies to enhance the catalytic performance of carbon materials, including non-metallic doping, metal doping, and carbon-based composites, and summarizes the new active sites formed by these strategies, as well as the connection between the types of active species produced by activated persulfate. In conjunction with the existing studies on the degradation of antibiotics by activated persulfate in carbon-based materials, the mechanisms of activation of persulfate by carbon-based materials (including free radicals, single-linear oxygen, electron transfer, and high-valent metal-oxygen species), and the methods to identify and determine the active species are concluded. Finally, the susceptible oxidation sites of tetracyclines, sulfonamides, and fluoroquinolones antibiotics, their linkages with active species, as well as the application of this technology in treating antibiotic-containing waters. These results can provide a reference for the development of carbon-based catalysts with high catalytic performance and stability, and their application to activated persulfate systems for efficient antibiotic degradation.

The bimetallic NiCe-x(x=1:3, 2:2, 3:1, 0:1, 1:0) catalysts were successfully synthesized using the hydrothermal method and subsequently evaluated for their efficacy in the selective catalytic reduction of NO by CO(CO-SCR). The results indicated that compared to NiO and CeO₂ catalysts, the NiCe composite catalyst exhibited superior performance in simultaneously removing low-temperature CO and NO. Superior performance was demonstrated by the NiCe composite catalyst with a 3:1 ratio, which achieved over 90% NO conversion over an extensive temperature range of 200~450℃ and exhibited strong resistance to SO₂ and H₂O. Characterization indicated that the existence of Ni and Ce ions led to an increased specific surface area and accelerated redox cycling (Ce³⁺+Ni³⁺↔Ce⁴⁺+Ni²⁺), which improved denitrification activity. In-situ DRIFTS findings confirmed that adsorbed NCO played a crucial role as an intermediate in the CO-SCR process employing NiCe-3:1.

In advanced oxidation processes (AOPs) based on peroxymonosulfate (PMS), efficient activation and utilization of PMS was considered to be an important goal for the removal of organic pollutants. The piezoelectric effect driven by water flow was introduced into PMS activation in this study, using the prepared MoS₂/PVDF membrane as a piezoelectric membrane to remove tetracycline (TC) from water. The degradation efficiency of TC by MoS₂/PVDF membrane was 77.9% within 60min was showed in the results, with a reaction rate constant of 0.0231min^-1, which was higher than that of MoS₂ (0.0135min^-1) and PVDF (0.0085min^-1). Sacrificial agent experiments combined with LC-MS were used to explore the intermediates of the TC degradation process and analyze the reaction mechanism. In cycling experiments, the excellent reusability and recyclability was exhibited in MoS₂/PVDF membranes. These results indicated that under the mechanical vortex force of water flow, MoS₂/PVDF membrane can trigger piezoelectric potential and generate abundant free electrons to activate PMS, thereby producing various active substances to degrade organic pollutants.

PM_2.5 control in the Guanzhong region has achieved significant progress, but the situation regarding ozone pollution remains severe. To continue advancing the fine management of VOCs (volatile organic compounds) in the Guanzhong region, with Xi'an and Xianyang as representatives, six industries—packaging printing, electronic product manufacturing, industrial coatings, paint and ink manufacturing, furniture manufacturing, and rubber products — were selected for sample collection. This study examines the VOC emission profiles, ozone formation potential (OFP), and secondary aerosol formation potential (SOAFP) of typical industries in the Guanzhong region. The results show that in the packaging printing and industrial coating industries, the primary VOCs emitted are oxygenated volatile organic compounds (OVOCs) (53%~73%) and alkanes (17%~34%); in the electronic product manufacturing industry, they are OVOCs (68%) and alkenes (29%); in the paint and ink manufacturing industry, the main VOCs are OVOCs (61%) and aromatic hydrocarbons (22%); in the furniture manufacturing industry, the primary VOCs are aromatic hydrocarbons (78%) and OVOCs (19%); and in the rubber products industry, alkanes (78%) dominate. Key characteristic species emitted by typical industries in the Guanzhong region include ethanol, acetone, isopropanol, formaldehyde, ethyl acetate, and m-/p-xylene. Based on the Maximum Incremental Reactivity (MIR) method and the Aerosol Formation Coefficient (FAC) method, it was found that OVOCs, aromatic hydrocarbons, and alkenes are the main contributors to OFP, while aromatic hydrocarbons are the primary source of SOAFP. The major emission sources are the paint and ink manufacturing, industrial coatings, and furniture manufacturing industries, which should be prioritized for control.

To investigate the causes of sludge bulking during high load operation of activated sludge and the control effect of adding vanillin, this study examined the overall changes in microbial community, filamentous bacteria genus, extracellular polymeric substance secreting bacteria genus, and functional gene clusters involved in exopolysaccharides synthesis when operating under conventional load or high load with or without vanillin addition. The results indicated that after sludge bulking occurred, there was a decrease in the proportion of proteins to polysaccharides in extracellular polymeric substances. This reduction limited the ability of proteins to act as a biological flocculant and resulted in poorer settling performance of the sludge. The causes of sludge bulking during high load operation were attributed to filamentous bacteria dominated by Sphaerotilus and viscous bulking led by Flavobacterium. The addition of vanillin effectively inhibited the proliferation of Sphaerotilus but still allowed for viscous bulking dominated by Thauera and Zoogloea. Metagenomic sequencing analysis revealed that the abundance of alg, eps, and pel functional gene clusters involved in exopolysaccharide synthesis increased by 0.4~0.5 times, 0.8~1.1 times, and 10.3~15.7 times, respectively. These findings suggest that these gene clusters may be potential factors contributing to the substantial increase in exopolysaccharide content observed in bulking sludge.

Passive convergence-permeable reactive barrier (PC-PRB) is an eco-friendly and sustainable in-situ groundwater remediation technology. Based on mathematical models of groundwater flow and contaminant transport, this study innovatively proposed a grid self-adaptive refinement algorithm and developed a contaminant convection-diffusion numerical simulation software PRB-Trans. Utilizing PRB-Trans, the impact of the decompression convergence process on the contaminant capture performance of PC-PRB was analyzed. Under given simulation contaminant source conditions, compared with the continuous permeable reactive barrier (C-PRB), the required PRB length (L_PRB) and PRB height (H_PRB) of PC-PRB were reduced by 40.0% and 70.0%, respectively. The PC-PRB's planar and cross-sectional contaminant treatment efficiencies were increased by 102.9% and 348.3%, respectively. The results of the investigation of influencing factors show that with the increase of the drainage pipe length (L_p), the required L_PRB and H_PRB of PC-PRB decreased, but the reduction rate gradually decreased. Simultaneously, the PRB thickness (H_PRB) increased significantly, leading to an increase in the PRB filler volume. To avoid this situation, it is recommended that the L_p/L_PRB ratio is less than 2. In addition, due to the mixing and matching function of the decompression convergence wells and the uniform water distribution function of the buffer layer, PC-PRB can effectively solve the problems of low filler utilization rate and local breakthrough of C-PRB, demonstrating its application potential in the field of groundwater remediation.