To efficiently remove residual antibiotics and mitigate ecological risks, h-BN/ZnFe2O4 composites were synthesized via a self-template solvothermal method. The material features 3D yolk-shell ZnFe2O4 substrate coated with 2D h-BN nanosheets. Under visible light, the composite exhibits high catalytic activity (97.58 % TC degradation in 120 min) and excellent cycling stability. Enhanced photocatalysis originates from: (1) increased light-harvesting efficiency via the 2D/3D yolk-shell structure; (2) extended spectral response and possible defect-mediated optical transitions introduced by h-BN; and (3) improved charge separation and transfer efficiency enabled by intimate interfacial contact. Comprehensive characterizations including XRD, FTIR, XPS, SEM, TEM, PL, EIS, and BET confirm the structural integrity, large surface area, and effective electron-accepting role of h-BN. Active species trapping experiments and ESR analysis revealed that center dot OH, center dot O-2(-), and h(+) play dominant roles in the photocatalytic process. In addition, HPLC-MS analysis identified major degradation intermediates, from which plausible degradation pathways were proposed. The developed 2D/3D h-BN/ZnFe2O4 heterojunction provides a novel strategy for efficient TC degradation. The yolk-shell structure's stability and high catalytic performance validate this design for fabricating efficient, stable catalysts.

Emerging Contaminants (ECs) in water bodies pose significant environmental concerns. Adsorption technology, known for its low cost, high efficiency, and ease of use, is a promising solution for ECs removal. This study investigated the adsorption performance of MIL-101(Fe), an iron-based metal-organic framework (MOF), for ECs with different molecular sizes. Sodium p-perfluorous nonenoxybenzenesulfonate (OBS), diclofenac sodium (DCF), and tetracycline hydrochloride (TCH) were selected as representative ECs, covering PFAS substitutes, NSAIDs, and antibiotics. MIL-101(Fe) exhibited specific surface area, excellent mesoporous structure and abundant surface active sites, enabling efficient adsorption. Under optimized conditions (pH = 5.8, 6, and adsorbent dosages 9, 40, 20, and 20 mg), removal efficiencies for OBS, DCF, and TCH reached 95.9 %, 97.5 %, and 86.4 %, respectively. Cyclic tests showed stable performance after five adsorption-desorption cycles. Kinetic studies indicated that OBS followed a pseudo-first-order model, while DCF and TCH adhered to a pseudo-second-order model. The maximum adsorption capacities for OBS, DCF, and TCH were 945.1, 1595.9, and 439.5 mg center dot g-1, respectively. Adsorption mechanisms revealed that smaller molecules like OBS and DCF easily entered the mesopores, while larger TCH molecules faced diffusion restrictions. The molecular interactions among OBS, DCF, and TCH involved electrostatic attraction toward-SO3-groups and pore filling in OBS, diffusion into the pore interior followed by hydrogen bonding with-NHS and it-it stacking in DCF, and surface-confined hydrogen bonding with-OH/-NHS and it-it interactions in TCH. This study provided a theoretical basis for efficient treatment of ECs with various molecule structures by Fe-MOFs adsorption materials.

Extensive application of antibiotics has led to antibiotic contamination in aquatic environments, posing global environmental and health challenges. This study pioneered periodically reversed electrocoagulation (PREC) as a process intensification strategy resistant to electrode passivation for the degradation of β-lactam antibiotics, using cefixime (CFX) as a model contaminant. Under baseline conditions (a current intensity of 0.6 A, pH of 7.0, and stirring speed of 600 r/min), Al–Zn electrodes achieved 97.4% removal of CFX (at an initial concentration of 20 mg/L). Response surface methodology (RSM) further enhanced removal efficiency to 98.8% (at a current intensity of 0.78 A, pH of 6.28, stirring speed of 613 r/min, and reaction time of 47.56 min), approaching the theoretical limits of 99.4% as predicted. Furthermore, the removal mechanisms were elucidated through analysis of flocs and CFX solutions. CFX is primarily adsorbed onto ZnAl2O4 flocs, while hydroxyl radicals (·OH) generated during the PREC process destroy aromatic rings and C=C bonds. The proposed degradation pathways involve hydroxylation, carboxylation, cleavage of C–N bonds, and benzene ring opening, followed by mineralization to H2O and CO2. Numerical simulations of the electric and flow fields revealed uniformly distributed intermediate potentials between electrodes, with electrolytic byproducts primarily accumulating near electrode surfaces. Variations in electrode configuration and flow velocity were found to affect the CFX removal efficiency. The intrinsic anti-passivation design and synergistic adsorption–oxidation of PREC provide a chemical-free and industrially adaptable solution for the treatment of recalcitrant antibiotics in water.

Nitrate pollution poses a significant threat to aquatic ecosystems and public health due to its high solubility and mobility in groundwater. Microbial electrolysis cells (MECs) offer a promising approach for nitrate removal from water; however, their denitrification efficiency remains limited. A composite cathode consisting of reduced graphene oxide-modified carbon cloth further electrodeposited with riboflavin (RF/rGO/CC) was employed in MECs to enhance denitrification performance. Over a 10-day operational period, the residual nitrate concentration in the catholyte of the RF/rGO/CC group decreased to 34.48 % of the initial level, compared with 54.33 % in the unmodified carbon cloth group. Scanning electron microscopy and confocal laser scanning microscopy revealed significantly increased biofilm density and microbial viability on the modified cathode. Electrochemical analyses confirmed that the RF/rGO/CC electrode exhibited superior electrochemical activity, which was reflected by a higher nitrate reduction peak observed in CV and a lower charge transfer resistance revealed by EIS. Moreover, the modified cathode enriched electroactive denitrifying bacteria and significantly increased the abundances of key functional genes involved in the denitrification pathway, including napA, narG, nirK, nirS, and nosZ. This study presents a promising strategy for enhancing nitrate removal efficiency in bioelectrochemical systems through cathode surface modification.

Photocatalysis has emerged as an economical, facile, and efficient strategy for combating aqueous environmental pollution. A novel 0D/2D hierarchical h-BN/Fe2O3 composite photocatalyst was developed through solvothermal synthesis for visible-light-responsive degradation of tetracycline (TC) in aqueous systems. The h-BN particles exhibited strong interfacial coupling with hexagonal Fe2O3 nanosheets, creating a well-ordered heterostructure. Advanced characterization techniques were utilized to systematically investigate the surface morphology and microstructure. Photoelectrochemical analyses demonstrated improved charge transfer kinetics, whereas controlled photocatalytic experiments under visible light irradiation quantitatively assessed degradation efficiency and parametric dependencies. The optimized 10 % h-BN/Fe2O3 composite material exhibited excellent photocatalytic activity. In the h-BN/Fe2O3/Vis/PMS system, the TC degradation rate was 92.12 % within 30 min and the final degradation rate was 93.94 %.Increasing the original H-BN degradation rate by 18.5 %, while Fe2O3 reaches 31.22 %. The enhanced performance originated from dual synergistic mechanisms, h-BN integration substantially extended Fe2O3's visible-light harvesting capacity, and the engineered Z-scheme heterojunction promoted directional migration of charge carriers at the interface. Mechanistic studies confirmed hydroxyl radicals (center dot OH) and superoxide anions (center dot O2- ) as primary active species, with degradation pathways rigorously verified through intermediate identification. This study establishes a dual contribution, a scalable protocol for engineering h-BN-based composites for antibiotic remediation, and fundamental principles for constructing visible-light-active heterojunctions, thereby creating a theoretical framework for industrial implementation.

The study of methane diffusion within coal is a critical theoretical foundation for coalbed methane extraction technologies. Currently, the development of coalbed methane resources is significantly constrained by the high-stress and low-permeability characteristics of deep coal seams. This necessitates an urgent focus on investigating the diffusion behavior of methane within the deep coal seams. This study investigates the stepwise diffusion characteristics of methane in coal under high-stress conditions. A series of experiments were carried out using a specially designed experimental apparatus aimed at this purpose to investigate the behavior of methane diffusion and to determine the dominant diffusion patterns in high-stress conditions. A diffusion model was constructed to calculate the diffusion coefficients of coal under high-stress conditions, which were then employed to perform numerical simulations of methane extraction based on the identified stepwise diffusion patterns. This analysis enabled the exploration of more economical and efficient methods of methane extraction. The results indicate that the adoption of a multistep diffusion pathway can effectively enhance methane desorption. When the diffusion pathways are uniform, the amount of desorption in the higher-level diffusion stage surpasses that in the lower-level diffusion stage. Additionally, the methane diffusion coefficient increases with a greater diffusion pressure gradient; however, simply increasing the diffusion pressure gradient does not necessarily lead to a significant increase in the desorption. Based on these findings, an intelligent extraction method was proposed, which enhances methane extraction efficiency while remaining economically viable and effective. The outcomes of this research provide theoretical support for understanding the mechanisms underlying methane extraction in high-stress coal seams.

Landfill leachate and concentrates from nanofiltration (NF) and reverse osmosis (RO) processes pose potential environmental threats. This study investigates the seasonal variations in the physicochemical properties and acute toxicity of landfill leachate and concentrates from Shenyang, Liaoning, China. The hydrophilic matter (HyI) constituted the major component of dissolved organic matter (DOM) in landfill leachate (68.18% on average). Humic substances were enriched in NF and RO concentrates, accounting for 86.92 and 62.78%, respectively. Landfill leachate exhibited strong toxicity to Artemia salina, particularly in summer. Although biotreatment processes reduced toxicity, the concentrates remained toxic. Principal component analysis (PCA) revealed significant correlations between physicochemical variables and toxicity. Discriminant analysis indicated that certain variables could predict acute toxicity. This study highlights the need for effective management of landfill leachate and concentrates on mitigating environmental risks.

The impact of pulsed electric field (PEF) on Fe(II)-assisted anaerobic ammonium oxidation (anammox) system remains unclear. This study investigated the effects and mechanisms of PEF on Fe(II)-assisted anammox system at 15 degrees C under varying nitrogen loads. The results showed that under a high nitrogen load of 6.6 kg-N/(m3-day), PEF significantly enhanced the performance of Fe(II)-assisted anammox system, increasing the total nitrogen removal by 14.3 %. Additionally, PEF enhanced the activities of anammox related enzymes such as HZS, HDH and heme c by 110.8 %, 73.6 % and 102.1 %, respectively. Molecular ecological network analysis showed that PEF facilitated the community symbiosis and enhanced the potential collaboration of the community. PEF greatly enhanced the abundance of Candidatus Kuenenia by 52.2 %, correspondingly promoting the capacity of anammox metabolism. The results indicated that PEF could improve the stability and effectiveness of Fe(II)-assisted anammox system under high nitrogen loads, benefiting the development of Fe(II)-assisted anammox technology.

Persistent pharmaceutical and personal care products (PPCPs) such as diclofenac (DCF) were inadequately removed by conventional wastewater treatments, posing global water contamination issues. This study addressed this issue by investigating efficient DCF removal using novel PREC with Al-Zn electrodes, optimized via conventional experiments and Response Surface Methodology (RSM). Exceptional DCF removal (93.7

Constructing a direct Z-scheme heterostructure is an effective way to improve photogenerated charge separation efficiency. In this work, a novel BiVO4/g-C3N4 (BVO/CN) Z-scheme heterojunction was successfully fabricated through a liquid film combustion method and ultrasonic desperation technique. The obtained samples were analyzed by serials characterization techniques, such as XRD, FT-IR, XPS, SEM, HRTEM, EDS, BET, UV-vis, and PL. The results demonstrated a strong integration between CN and BVO, as evidenced by the absorption edge shifting to 520nm and revealing a narrow band gap (Eg=2.47eV), thereby enhancing light absorption capacity. Under visible light irradiation, the removal efficiency of levofloxacin (LVFX) reached 97.7% within 40min using 20 BVO/CN, which was respectively 2.03 and 2.21 times higher than that achieved with BVO or CN alone. The mechanism of the BVO/CN Z-scheme heterojunction was elucidated based on the ESR test and radical trapping experiment. Additionally, the potential degradation pathway of LVFX was analyzed using HPLC-MS. This study demonstrates the feasibility of constructing a Photocatalyst/Visible-light/peroxymonosulfate (PMS) system for mitigating antibiotic-induced ecological pollution.

Roasting technology is increasingly used in the beneficiation of refractory iron ores. During the roasting process, the presence of pyrite in some iron ores leads to the formation of SO2, requiring effective sulfur fixation techniques. This study proposed an innovative in-situ sulfur fixation method by pre-oxidation roasting, in which sulfur was fixed during the oxidation roasting process before reduction roasting. The effects of the main iron mineral (hematite), primary gangue mineral (quartz), and common calcium-containing carbonate minerals (calcite and dolomite) on sulfur migration during pyrite roasting were investigated, with particular emphasis on the sulfur fixation capabilities of calcite and dolomite. The study included thermodynamic equilibrium analysis, phase transitions and microstructural evolution in different reaction systems. The results showed that calcite and dolomite effectively reduced SO2 emissions by forming CaSO4 and MgSO4, with calcite exhibiting a stronger sulfur fixation capacity for the same mass. Kinetic analysis indicated that pyrite pyrolysis followed a two-step random nucleation and growth model. Furthermore, the addition of calcite increased the apparent activation energy of SO2 formation and altered the reaction pathway, providing insight into the sulfur fixation mechanism of calcite from a kinetic perspective.

This study focused on analyzing the contamination status of groundwater around an oil depot in Fuxin by considering physicochemical indexes, potentially toxic elements (PTEs), and organic substances with reference to relevant standards. The hazard analysis using the Nemero contamination index and potential ecological hazard index method, aimed at determining the levels of PTEs and organic contaminants in the groundwater, revealed a mild ecological risk in the study area. A redundancy analysis-geographic information system employed to uncover the sources of PTEs in groundwater samples revealed two main components: the first comprised Cd, Zn, Mn, and Pb, which were mainly of anthropogenic origin (oil reservoir leakage), and the second component includes Cr, Hg and As, which may originate from anthropogenic and geological sources. Evaluation of the carcinogenic and noncarcinogenic risks associated with PTEs indicated high levels of the former in the study area. Finally, the correlation between organic pollutants and environmental factors and the natural attenuation trend was explored. This exploration aimed to provide a reference for groundwater contamination investigation, formulation for contamination prevention and control strategies in relevant demolition areas, and theoretical guidance and technical support for subsequent analysis and monitoring of field data.

Effects of different electric field intensities on the anammox process were investigated. The results showed that the suitable electric field intensity could dramatically enhance the anammox growth rate and granule sludge stability under a higher nitrogen loading shock. The cellular yield and anammox amount of R2 (0.3 V/cm) was significantly enhanced by 186.48

Geopolymer technology is an effective method of fly ash (FA) disposal developed in recent decades. This study provided a novel technology based on geopolymerization for FA resource, which could solve the problem of long-term heavy metal leakage trends. Firstly, Unconfine compressive strength (UCS) of geopolymer and the heavy metals leaching test was taken to discuss the effects of oxidize species. The results indicated that the UCS of geopolymer samples was increased with the increase of CaO, and the largest 28 d UCS was 24.8 MPa when CaO content was 31.5%. When the CaO content was 32%, the leaching concentration of heavy metals was the lowest (Pb2+ was 0.02 mg L-1, Cd2+ was 0.01 mg L-1), and the solidification rate of heavy metal ions were more than 93.6%. Secondly, two methods were used to evaluate the corrosion resistance of FA based geopolymer. The observations suggested that the FA based geopolymer exhibits a high level of resistance to erosion caused by sulfate ions and chloride ions. Thirdly, carbonation tests were taken to discuss the durability of FA based geopolymer. The results shown that UCS exhibited a modest rise following the process of carbonation, and then demonstrated a stable trend after a period of 28 days, and the heavy metal leaching test results that comply with the limitations specified in the national standard at 7, 14, 28, and 56 days. The findings from accelerated carbonization tests at 56 days, determined by empirical equations, suggest that the carbonization age of geopolymers is projected to be 102 years. Finally, XRD, FTIR and SEM were taken to discuss the microstructure characterization of FA based geopolymer, and solidification mechanisms of heavy metal ions by geopolymer materials could be concluded as gelation, physical encapsulation, and chemical reactions. This study employed geopolymerization technique to solidify MSWI fly ash, aiming to facilitate its reutilization. The FA based geopolymers exhibit strong durability and mechanical qualities, making them suitable for a variety of applications.

The use of geopolymers for the solidification/stabilization (S/S) of municipal solid waste incineration fly ash (MSWI FA) is promising because the Cao in MSWI FA can provide an alkaline environment to facilitate geopolymer reactions and help to form the gel phase in the solidified body. This study investigated the role of CaO in MSWI FA in immobilizing common heavy metals, especially Cd2+ and Pb2+. Tests were performed to evaluate the effect of CaO on the unconfined compressive strength (UCS) of the polymer and the leaching of heavy metals. The findings revealed that as the CaO content increased, the UCS of the geopolymer samples also rose, reaching a maximum 28-day UCS of 24.8 MPa at a CaO content of 31.5%. Additionally, higher CaO levels resulted in lower leaching concentrations of heavy metals in the stabilized material. When the CaO level is 32%, the levels of heavy metals that leach out are very low, with Pb2+ at 0. 02 mg/L and Cd2+ at 0. 01 mg/L, achieving a stabilization rate of over 93.6% for these ions. Moreover, the geopolymer’s characteristics were analyzed by XRD, FTIR, and SEM, and the immobilization mechanisms of Cd2+ and Pb2+ were identified as gelation, physical encapsulation, and chemical substitution.

Pyrite, a common iron mineral in refractory iron ores, emits SO2 2 during oxidative roasting, contributing to environmental pollution. This study investigated the effect of calcite on the thermal decomposition of pyrite, focusing on thermodynamics, phase transformation, microstructural evolution, and non-isothermal kinetics, with emphasis on SO2 2 formation inhibition. Results showed that pyrite decomposed first to pyrrhotite, then to magnetite and hematite, with SO2 2 as the primary gaseous product. Higher temperatures and lower oxygen concentrations favored S2 2 gas formation. Non-isothermal decomposition of pyrite occurred between 400-725 degrees C, degrees C, initiated at the particle surface, and significantly increased product porosity, resulting in butterfly-shaped hematite. The addition of calcite resulted in the reaction of SO2 2 with calcite to form anhydrite on the particle surface, inhibiting the release of SO2. 2 . Initially, the thermal decomposition of pyrite proceeded with a low apparent activation energy, making the reaction relatively easy. However, the presence of calcite significantly increased the apparent activation energy and inhibited the thermal decomposition reaction.

Tropical cyclones have resulted in casualties and economic losses in the areas surrounding the Bay of Bengal (BoB). Thus, a comprehensive investigation of these tropical cyclones holds vital implications for disaster preparedness and mitigation. This paper compares the occurrence of storms in the last two decades, i.e., 2002–2011 and 2012–2021, and results reveal that such storms exhibited predominantly a northwesterly track towards the northwestern BoB, with a severer intensity but equal total storm frequencies. Over the past decade, a southeast-northwest pathway (SNP) was identified, demonstrating a higher incidence of severe tropical cyclones (STC, with lifetime maximum intensity ≥ 64 knots) over the BoB. Further analysis of the changes in the environmental conditions between these two decades indicates that a southeasterly anomaly in the steering flow contributed to the formation of the SNP. During the same period, the more favorable oceanic conditions during the last decade, including higher sea surface temperatures, a greater upper ocean heat content, a thicker warm water layer, and a thicker barrier layer beneath the SNP, favored the development of these storms by providing more heat energy to the storms. The atmospheric conditions, including increased air-sea heat fluxes, moisture, and instability within the lower troposphere, as well as reduced vertical wind shear, facilitated the development of convection within these storm systems. These favorable conditions improved the potential for storm development into STCs and elevated the risk of the northwestern BoB being impacted by more destructive storms.

Electrochemical-assisted microbial degradation technology was considered a crucial strategy to reduce micropollutants, but the mechanism of the pulsed electric field (PEF) in affecting biodegradation had not been systematically studied. This study aimed to construct a bio-electrochemical system (BES) using PEF to investigate its effect on the degradation of triclosan (TCS) by the aerobic bacterium Bacillus sp. DL4. The operating optimal parameters for the BES (i.e. 0.01 A of the pulsed current, 1000 Hz of the pulse frequency, Fe (+)-C (-) of the plate materials, 4 cm of the plate spacing) were obtained by batch experiments. The maximum biomass (OD600 = 1.0 ± 0.05) was achieved and the removal efficiency of TCS reached above 95% in 24 h under the obtained operating conditions. Meanwhile, a thorough and methodical investigation of the metabolites in strain DL4 stimulated by PEF using untargeted Liquid Chromatography - Mass Spectrometry (LC-MS). In multivariate analysis, the experimental groups showed a notable separation in Principal Components Analysis (PCA) and Orthogonal Partial Least Squares Analysis discriminant analysis (OPLS-DA) score plots. A total of 3181 differential metabolites were obtained, and the up-regulated metabolites were mainly related to 'Aminoacyl-tRNA biosynthesis', 'Arginine and proline metabolism', 'Lysine degradation', 'ABC transporters', and 'TCA cycle', implying that PEF enhanced the degradation efficiency of TCS by enriching functional genes with transport ability and ion migration ability in cells. This study illuminated how PEF can affect TCS biodegradation and gives insights into the application prospect of electrochemical-assisted biodegradation technology in water environment treatment.

Water pollution is a significant global environmental concern that threatens the sustainable progress of humanity. In this study, the concepts of photocatalytic oxidation in the cathodic zone (NH4+-N adsorption-NH3-N conversion) and electrochemical oxidation in the anodic zone (NH4+-N direct oxidation + chlorination) were proposed to remove ammoniacal nitrogen, and experimental studies were conducted. The stirring of the test solution during the reaction process enhanced the ammoniacal nitrogen removal efficiency by ∼9% after 90 min of reaction. The removal efficiency of ammoniacal nitrogen was comparatively high at low concentrations. After 60 min of reaction in the presence of 15 mg·L−1 ammonium chloride, the removal efficiency exceeded 95%; the removal efficiency of ionized ammonia increased with increasing current density. After 60 min, the removal efficiency of ammoniacal nitrogen exceeded 80%. Under the same ammoniacal nitrogen concentration conditions, the ammoniacal nitrogen removal efficiency in the test solution increased with the increase in the chlorine ion concentration, and in the absence of chlorine ions, ammoniacal nitrogen removal in the electrochemical reaction environment was insignificant. Under the same power and light conditions, the photoelectrochemical reaction exhibited a ∼15% higher ammoniacal nitrogen removal efficiency than electrochemical oxidation.

Overusing triclosan (TCS) endangered ecological safety and human health, and the pandemic of COVID-19 aggravates the accumulation of TCS in the aquatic environment. Therefore, reducing residual TCS concentrations in the environment is an urgent issue. An aerobic bacterium, Bacillus sp. DL4 was isolated with the capability of TCS biodegradation. Response surface methodology (RSM) and artificial neural network (ANN) were carried out to optimize and verify the different condition variables. All the variables were linear and the interaction of the three factors significantly affected TCS removal at the quadratic level (p < 0.001). Under the optimal conditions (35℃, initial pH 7.31, and 5% strain DL4), the TCS removal rate of 95.89 ± 0.68% was observed and found to be consistent with the predicted values from RSM and ANN models. In addition, statistical comparisons between the models indicated that the ANN model had a stronger predictive capability than the RSM model. Kinetic studies showed that TCS degradation was consistent with a pseudo-first-order kinetic model. Whole genome sequencing indicated that many functional genes were involved in and facilitated TCS degradation. Main metabolite products were detected and identified during the biodegradation process by LC-MS, and a possible degradation pathway was tentatively hypothesized. Overall, this study provides a theoretical foundation for the characterization and mechanism of TCS biodegradation in the environment by Bacillus sp. DL4.