Regional-scale mobile observations of atmospheric isoprene were conducted along a 2000km east-west transect in China's subtropical forest region using a mobile laboratory equipped with a high-resolution proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS). The objective of this study was to elucidate the spatial distribution patterns of isoprene in this area. The results revealed significant spatial heterogeneity in isoprene concentrations, with an average value of (0.635 ± 0.204) μg/m³. The isoprene concentration in the Jiangnan forests, characterized by widespread bamboo and predominantly subtropical evergreen broadleaf species, was (0.629 ± 0.116) μg/m³, which was approximately 32.8% higher than the (0.474 ± 0.155) μg/m³observed in the Guizhou forests, primarily composed of conifers. These findings indicate that the spatial distribution and emission intensity of isoprene in forested areas are significantly influenced by vegetation composition. Moreover, in the industrially dense Zhejiang region, the isoprene concentration reached (0.881 ± 0.155) μg/m³, representing increases of 86.2% and 40.1% compared to the Guizhou and Jiangnan forests, respectively. These results suggest that in addition to the rich diversity of plant species, anthropogenic factors such as industrial and traffic activities also likely contribute to the elevated isoprene concentrations observed in this region.

To clarify the concentration characteristics and sources of volatile organic compounds (VOCs) in a typical northwestern petrochemical park during summer, continuous monitoring of 116 VOCs was conducted from June to July 2024. The measured VOC (MVOCs) concentrations were obtained, and the initial VOC (InVOCs) and consumed VOC (CVOCs) concentrations were calculated. Whereafter, the positive matrix factorization (PMF) was used to analyze the sources of MVOCs and InVOCs, the principal component analysis (PCA) was employed to identify the sources of CVOCs, and the contribution of the major factors of each VOC source to ozone (O₃) formation was also calculated. The results indicated that during the observation period, oxygenated VOCs (OVOCs) and alkanes exhibited the highest concentration contributions among both the measured total VOCs (M-TVOC) and the initial total VOCs (In-TVOC), with a diurnal variation characterized by bimodal peaks in the morning and evening. The consumed total VOCs (C-TVOC) exhibited a strong correlation (r = 0.89) with the diurnal variation of O₃ concentrations, with alkenes and OVOCs being the dominant contributing species. Among the top ten ozone formation potential (OFP) species for all three VOCs categories, alkenes and aldehydes were predominant. .The sources of MVOCs and InVOCs were ranked as follows: petrochemical sources > combustion sources > vehicle emissions > biogenic emissions > solvent utilization sources.. As for CVOCs, the sources were identified aspetrochemical sources (51.1%) > gasoline evaporation (26.0%) > biogenic emissions (18.2%) > solvent utilization sources (4.8%). Among these, petrochemical sources were identified as the largest contributor to O₃formation. The results indicated that reducing emissions from petrochemical sources, combustion sources, and vehicle emissions is an effective strategy for controlling summer VOCs around the park. Additionally, cutting emissions from petrochemical sources and solvent utilization sources can significantly decrease the contribution of VOCs to O₃ formation.

Dominated crops Triticum aestivum, Zea mays, Glycine max, and Arachis hypogaea were selected to study the Volatile Organic Compounds (VOCs) emission characteristics and their atmospheric reactivity of crop. The dynamic enclosure system and the thermal desorption and gas chromatography-mass spectrometry (TD-GC-MS) technique were used for the quantitative analysis of VOCs emission. The VOCs emission rate and chemical composition characteristics of four crops were studied, and their hydroxyl radical consumption rate (L_OH) and O₃ formation potential (OFP) were calculated. The results showed that the total VOCs emission rates of four crops were ranked as Arachis hypogaea ((43.27 ± 18.8) μg/(g·h)) > Triticum aestivum ((21.63 ± 8.24) μg/(g·h)) >Glycine max ((2.97 ± 0.67) μg/(g·h)) > Zea mays ((0.36 ± 0.15) μg/(g·h)). The major emission contributing components of each crop included isoprene, n-heptane, cyclopentane, p-xylene, and m-xylene. The composition of VOCs emitted by the four crops were different. Triticum aestivum mainly emitted alkanes and aromatics, Zea mays mainly emitted monoterpenes, Glycine max mainly emitted alkanes, and Arachis hypogaea mainly emitted isoprene. Alkenes were detected only in VOCs emitted from Glycine max. The L_OH and OFP of VOCs emitted by different crops also followed the same ranking: Arachis hypogaea > Triticum aestivum >Glycine max > Zea mays. Isoprene, limonene, trans-β-ocimene, β-caryophyllene, and cyclopentane were the key active components of VOCs emitted by the four crops.

As a typical photochemical product, atmospheric peroxyacetyl nitrate (PAN), which has received widespread attention for the important role it plays in atmospheric photochemical processes, has been studied relatively late due to difficulties in monitoring. In order to deeply investigate the concentration level of PAN and its generation mechanism in industrial cities, this study conducted online observations of PAN and other pollutants for one year from March 2023 to February 2024 in Zibo City, North China Plain. The average concentration of PAN during the study period was 1.09×10^-9 (0.03~10.07×10^-9), and the four-seasonal concentration ranking showed a pattern of winter (2.07×10^-9) > autumn (0.98×10^-9) > spring (0.64×10^-9) > summer (0.61×10^-9). There was a significant difference in the time of occurrence of the peak daily change concentration, with the peak occurring at midday (12:00) in summer and delayed to the afternoon (17:00) in winter. The results of the generalised additive model (GAM) showed that the PAN concentration was significantly affected by temperature and atmospheric oxidability. Calculations based on the zero-dimensional box model (F0AM) showed that acetaldehyde contributed the most to peroxyacetyl (PA) (69%), followed by photolysis (18%) and oxidation (11%) of methylglyoxal, and that the loss of PA was dominated by the interaction of nitric oxide (NO) (18%) and nitrogen dioxide (NO₂) (81%) with PA. The relative incremental reactivity (RIR) showed that PAN generation was sensitive to NO_x. This study enriches the understanding of the characteristics of atmospheric PAN pollution and its formation mechanism in North China and provides scientific and technological support for air pollution control.

Based on the chemical components in PM_2.5 and meteorological data from the online monitoring of Zibo Super Station, relevant analyses were conducted for the PM_2.5 pollution period from December 25^th, 2023 to January 6^th, 2024. The results showed that during the observation period, the average concentration of PM_2.5 was (133±67) μg/m³, and the average proportion of secondary inorganic ions (NO₃^-,SO₄^2- and NH₄⁺) was 58.3%. Among them, the concentration of NO₃^- was the highest, accounting for 26.9%. The average values of the sulfur oxidation ratio and nitrogen oxidation ratio were 0.46 and 0.29, respectively, both greater than 0.1, indicating that there was an obvious secondary formation process of SO₄^2- and NO₃^- during this pollution process. The formation of NO₃^- was mainly limited by HNO₃, and the heterogeneous reaction under high-humidity conditions was the main pathway for its formation. The Positive Matrix Factorization (PMF) model identified six main sources of PM_2.5, namely secondary nitrates (30.2%), secondary sulfates (26.8%), coal burning sources (18.4%), motor vehicle sources (15.3%), industrial sources (5.3%), and dust sources (4.0%). Concentration Weighted Trajectory (CWT) analysis further revealed the main contribution path areas of sources with a relatively large contribution to PM_2.5, such as secondary nitrates, which were mainly from the local area and surrounding cities.

The passive NO_x adsorbent, Pd-SSZ-13 with a Pd loading of 1.64wt.%, was prepared by the ion-exchange method. Then, the Pd-SSZ-13 was subjected to thermal and hydrothermal aging treatments separately for 10h under mild conditions: at a temperature of 700℃ and in an atmosphere consisting of 10%O₂, 2%H₂O (for hydrothermal treatment only), and N₂ as the balance. The effects of these treatments on the NO_x adsorption/desorption performance of Pd-SSZ-13 were investigated. The physicochemical properties of adsorbents and the NO adsorption process were characterized using N₂ adsorption-desorption, XRF, ICP-OES, XRD, SSNMR, XPS, TEM, NH₃-TPD and in situ Drifts techniques. The results showed that when the feed gas contained 2%H₂O, the SSZ-13 support was unable to adsorb NO_x, whereas Pd-SSZ-13 exhibited NO_x adsorption during both the adsorption stage and the temperature-programmed stage (100~230℃), demonstrating an adsorption capacity of 81.3μmol/g. The NO_x desorption temperature range (230~493℃) fell within the active temperature window of SCR catalysts, and complete NO_x desorption was achieved. After undergoing thermal and hydrothermal aging treatments, the NO_x adsorption capacity of Pd-SSZ-13 in the presence of H₂O further increased to 113.4 and 126.2μmol/g, respectively, and the thermally aged sample showed better cyclic stability. Although thermal and hydrothermal aging treatments induced partial dealumination of the SSZ-13 framework, they neither altered the micropore characteristics of SSZ-13 nor caused structural collapse or framework destruction. Instead, the aging processes promoted the migration of Pd species from external surfaces to interior pores, enhanced the dispersion of Pd, and increased the amount of Pd²⁺(Z-[Pd²⁺(OH)]⁺ and Z₂-Pd²⁺) sites, thereby improving the NO_x adsorption-storage capability of Pd-SSZ-13. Compared with the hydrothermally-aged Pd-SSZ-13, the thermally-aged sample showed less framework dealumination, a higher specific surface area and a larger micropore volume, and better dispersion of Pd species, all of which likely contributed to its superior cyclic stability. With H₂O in the feed gas, NO was mainly adsorbed and stored at the Pd²⁺ sites in the forms of Pd⁺-NO, Pd²⁺-NO and hydrated Pd²⁺-NO species, with the competitive adsorption of H₂O attenuated at elevated temperatures. During the thermal and hydrothermal aging of Pd-SSZ-13, the abundant Brønsted acid sites likely played an important role in facilitating the migration of Pd species and the formation of Pd²⁺ sites.

To explore the impact of the increase in new energy vehicles, such as LNG heavy-duty trucks and hybrid vehicles, on tunnel ventilation and to address the issue of ventilation flow calculation discrepancies caused by insufficient consideration of their emission characteristics in current design codes, this study builds a tunnel vehicle baseline emission factor library and a refined tunnel ventilation calculation method based on the emission characteristics of new energy vehicles. Factors such as slope and vehicle fleet composition are taken into account. The study uses the Huayan Tunnel as a case study and calculates the required ventilation flow for different penetration rates of new energy vehicles based on the updated emission factor library. The results are then compared with those obtained using the existing ventilation calculation methods. The results indicate that the refined method significantly improves the accuracy of the required ventilation flow calculation. When the design year is set to 2030, the required ventilation flow for NO₂ dilution is 305.5% higher than that calculated using the International Tunnel Ventilation Report (PIARC 2019) method, while the required ventilation flow for CO and VI dilution decreases by 10% and 6.5%, respectively. Additionally, for every 10% increase in LNG heavy-duty truck penetration, the required ventilation flow for NO₂ dilution increases by approximately 55%. In contrast, the impact of hybrid and pure electric vehicles on the required ventilation flow is negligible. The traditional design codes, which focus on CO and VI as the main control indicators, are no longer applicable to fleet structures with a rapidly increasing proportion of new energy vehicles. The required ventilation flow for NO₂ dilution will become a key control indicator for future tunnel ventilation design.

This study evaluated the interannual variations in the sources, source-specific metals, and health risks of PM_2.5-bound heavy metals (HMs) based on observational data in heating seasons from 2020 to 2022 in Wangdu County, aiming to assess the impact of "coal-to-gas" (CTG) policy on air quality at rural areas. The CTG policy continued to play a positive role, both PM_2.5 and 16HMs (Cr, Pb, Tl, Ba, Sb, Sn, Cd, Sr, As, Zn, Cu, Ni, Co, Fe, Mn, and V) showed a declining trend year by year with annual average reductions of 30.4% and 43.4%, respectively. Positive Matrix Factorization (PMF) model was used to analyze the sources of HMs and results indicated that the contribution of coal combustion (CC) decreased by an average of 11.8% annually. However, biomass burning (BB) increased year by year and leaped the largest contributor (33.7%) in the winter 2022, primarily driving by natural gas shortages and heating cost rises at rural areas. The concentrations of CC marker elements As and Pb decreased by 20.7% and 48.5% annually, and CC fractions declined by 15.6% and 13.5% per year, respectively. Similarly, the concentrations and fractions of BB marker element K increased by 20.6% and 7.4% annually. Industrial emissions (IE), vehicle emissions (VE), and fugitive dust (FD) all exhibited upward trends over the years. For health risk assessment: only As and Cr surpassed threshold of carcinogenic risks, and there were derived from CC and IE, therefore, CC and IE were identified as the main contributors to carcinogenic risks. However, individual elements did not exceed the threshold of non-carcinogenic risks, but the total carcinogenic risks persisted from 2020 to 2022. Specially, the total carcinogenic risks for children were 64%, which was much higher than 36% for adults. Together, adults only have non-carcinogenic risks in 2020, while children were always faced with non-carcinogenic risks. As a main contributor to both carcinogenic and non-carcinogenic risks for As, since the annual average contribution of CC to As emissions has dropped significantly by 15.6%, resulting in a year by year decline for carcinogenic and non-carcinogenic risks.

By constructing feature metagenome database of complete ammonia oxidizing bacteria (CAOB), their abundance and diversity in 56water treatment systems, e.g., urban wastewater nitrogen systems and drinking water treatment systems, were quantitatively analysed. The significant influencing factors were determined by statistical analysis and the influential mechanism were analysed. It was revealed that CAOB were accounted for 8.2%~99.6% of the ammonia oxidation community and 1.4%~48.6% of the Nitrospira in the surveyed urban wastewater nitrogen removal systems. Phylogenetic analysis revealed that CAOB metagenome assembled genomes (MAGs) were associated with Ca.Nitrospira nitrosa, with ANI value higher than 94%. CAOB community were more homogeneity than those in drinking water treatment systems, speculating that Ca.Nitrospira nitrosa cluster were specific adaptable to urban wastewater nitrogen removal systems. According to correlation analysis, pH value was significantly positively while COD was significantly negatively correlated with the abundance and diversity of CAOB. They were more likely to be dominant nitrifiers in low NH₄⁺, high sludge retention time, and low dissolved oxygen conditions. In conclusion, this study reveals that Ca.Nitrospira nitrosa cluster are dominant CAOB, and their distribution influencing factors in urban wastewater nitrogen removal systems.

To investigate the overall effects of carbon source types on wastewater treatment plant (WWTP) performance, this study compared the impacts of three external carbon sources—a composite carbon source, sodium acetate and glucose—on the overall operational process. The results demonstrated that different carbon sources led to variations in the metabolic performance of heterotrophic microorganisms. Under the influence of the three carbon sources, the heterotrophic yield coefficients Y_H were 0.703 (composite carbon source), 0.676 (sodium acetate), and 0.889 (glucose), respectively. The heterotrophic decay coefficients b_H were 0.405, 0.433 and 0.775d^-1, while the maximum heterotrophic growth rates μ_mH were 2.146, 3.071 and 6.078d^-1 respectively. Using GPS-X software, a model of the target WWTP was constructed and calibrated. The kinetic parameters under each carbon source were incorporated into the model for simulation. The results indicated that changes in kinetic parameters directly affected the treatment efficiency, energy consumption, sludge production, and greenhouse gas (GHG) emissions of the WWTP. In terms of total nitrogen removal efficiency, the composite carbon source and sodium acetate exhibited more significant advantages, albeit with increased energy consumption and GHG emissions. In contrast, while glucose was more energy-efficient and reduced carbon emissions, it resulted in lower nitrogen removal efficiency and potentially higher sludge production. After considering market pricing, the composite carbon source was found to be a more competitive option for denitrification.

This study integrated biological phosphorus removal into the PN-SAEPD process, establishing a PNPR-SAEPD system. To allocate the limited carbon source reasonably, the experiment gradually adjusted the two-stage anaerobic time ratio from 3:1 (90min:30min) in the S1stage to 1:1 (60min:60min) in the S2 stage, and then to 1:3 (30min:90min) in the S3stage. The study investigated the impact of the two-stage anaerobic time ratio on the conversion of influent organic matter, nitrogen and phosphorus removal performance, and microbial community structure of the PNPR-SAEPD system. The results showed that in the S2 stage, with a two-stage anaerobic time ratio of 1:1, the allocation of inflow organic carbon sources was most reasonable. The average COD consumed by the SAEPD and PNPR reactors for storing internal carbon sources was (89.3±8.4)mg/L and (82.6±7.7)mg/L, respectively. The phosphorus removal contribution of the PNPR reactor was (79.1%±8.5%), creating phosphorus starvation conditions for the subsequent anaerobic stage of the SAEPD reactor. The contribution of DPAOs in the SAEPD reactor to the storage of internal carbon sources was only 15%, consuming (10.1±4.0)mg/L of COD. The relative abundance of DPAOs dropped to 3.01%, enhancing the synergistic denitrification of DGAOs and AnAOB. Integrating biological phosphorus removal into the PN reactor improved the stability of short-cut nitrification, with the relative abundance of NOB gradually decreasing from 3.86% to 0.64% and NAR maintaining at around (82.1%±4.0%). In the S2stage, the superior PN performance of the PNPR reactor and the EPD pathway dominated by DGAOs in the SAEPD reactor provided sufficient electron acceptors for AnAOB. The anaerobic ammonium oxidation denitrification contribution remained at about (81.8%±3.6%), the total nitrogen removal rate was maintained at around (88.3%±1.6%), and the effluent total nitrogen concentration was below 10mg/L. The TP removal rate could reach up to 93.7%, and the effluent TP concentration was basically reduced to below 0.5mg/L.

This study proposes a strategy to inhibit nitrite-oxidizing bacteria (NOB) in the completely autotrophic nitrogen removal over nitrite (CANON) process by alternating long and short operational cycles. During long cycles, in-situ free ammonia (FA) was used to suppress NOB, while in short cycles, substrate inhibition was employed to continuously suppress NOB activity when FA concentrations fall below the inhibitory threshold for NOB. Two sets of SBR, R1 and R2, were operated with different long-short cycle alternation patterns. The results show that both R1 and R2 achieved good nitrogen removal efficiencies (NRE), with R2 slightly outperforming R1. The NRE for R1 and R2 were 78.73% and 85.41%, respectively, while the effluent NO₃^--N concentrations were 14.02mg/L and 7.21mg/L, respectively. At day 64, the specific nitrate production rates (SNPR) of R1 and R2 decreased to 2.88 and 1.95mgN/(gMLVSS·h), respectively, indicating effective suppression of NOB activity. Analysis of extracellular polymeric substances (EPS) revealed that the alternating long and short cycle strategy promoted microbial EPS secretion. The EPS content in R1 and R2 increased from 40.22mg/gVSS at inoculation to 86.41mg/gVSS and 97.79mg/gVSS, respectively. High-throughput sequencing results indicated that the dominant bacterial phyla in the system were Proteobacteria, Bacteroidota, and Planctomycetota. The growth of NOB, represented by Nitrospira and Nitrobacter, was inhibited in both R1 and R2. The relative abundance of Nitrospira decreased from 2.05% in the inoculated sludge to 0.18% in R1 and 0.11% in R2, while Nitrobacter abundance dropped from 1.97% to 0.06% in R1 and 0.05% in R2. Meanwhile, the abundance of AnAOB, (Candidatus_Brocadia) reached 8.92% (R1) and 9.14% (R2), and AOB, (Nitrosomonas) achieved abundances of 4.28% (R1) and 6.56% (R2), establishing a well-coordinated synergy.

An integrated fixed-film activated sludge system (IFAS) was used to treat simulated wastewater with high-strength ammonia and organics in this study. The shortcut nitrification and denitrification coupled with anammox was successfully achieved after 83d operation through stepwise increase of influent ammonia nitrogen concentration (50~300mg/L) and low oxygen control (DO: 0.15mg/L). With the increase of ammonia nitrogen concentration, effluent nitrite accumulated significantly. When the influent ammonia nitrogen concentration increased to 300mg/L, the removal efficiencies of COD, NH₄⁺-N and TN reached 95.3%, 100% and 93.1%, respectively, and the total nitrogen removal loading rate (NRR) reached 0.14kg/(m³·d). The microbial activity test showed that the anammox activity was higher in the biofilm phase, while ammonia aerobic oxidation activity was higher in the sludge phase. With the increase of ammonia nitrogen and COD concentrations, extracellular polymeric substance (EPS) secretion and protein/polysaccharide (PN/PS) increased, promoting stronger impact load resistance and biological stability of the system. Microbial community results found that heterotrophic nitrification and aerobic denitrifier (Acinetobacter), anammox bacteria (Candidatus Brocadia and Candidatus Jettenia) were mainly enriched in biofilm, while partial nitrification bacteria (Nitrosomonas) was distributed in sludge. The sludge-biofilm separation mode facilitates directed proliferation of different nitrogen-removing bacteria. Functional gene annotation (KEGG) suggests that collaborative nitrogen removal in the IFAS system is via heterotrophic nitrification/aerobic denitrification and partial nitrification denitrification/anammox.

The granulation process and pollutant removal performance of aerobic granular sludge (AGS) under conventional and micro-nano aeration modes were investigated, with focus on the roles of extracellular polymeric substances (EPS) and microbial community succession in mediating microstructural responses. Compared to conventional aeration, the micro-nano aeration exhibited superior oxygen mass transfer efficiency and higher hydroxyl radical (·OH) generation, leading to significantly enhanced pollutant removal. Ammonia and chemical oxygen demand (COD) removal efficiencies consistently exceeded95%, while total nitrogen removal remained at a high level of 78.81%. Micro-nano aeration also accelerated AGS granulation, with mean particle sizes surpassing300 μm within20days. XDLVO-based interaction energy calculations indicated favorable aggregation behavior under both aeration regimes. Due to the biofilm-promoting effects of micro-nano aeration system, AGS developed contained higher EPS content under this mode, with Hydrophobic TB-PN playing a key role in forming protein-based hydrophobic networks that promoted AGS granulation. In contrast, AGS stability in the conventional system was primarily maintained via ionic bridging by Ionic TB-PS. Distinct microbial community structures were observed between the two aeration modes. Conventional aeration favored typical denitrifying bacteria, whereas the intensified of micro-nano aeration system led to a proliferation of filamentous taxa, notably Neomegalonema, Thiothrix, and norank_f_Saprospiraceae. These filamentous bacteria contributed to EPS secretion and AGS structural integrity while maintaining stable nitrogen removal performance.

The typical low-C/N municipal wastewater (COD, ammonia, total nitrogen of 258.1, 30.5, 36.8mg/L) in South China was treated by membrane aerated biofilm reactor (MABR) process. By means of synchronously reducing hydraulic retention time (HRT) and increasing aeration pressure, the results showed that effluent COD met the discharge standard of level I class B, and effluent ammonia and total nitrogen met the discharge standard of level I class A at the individual HRT and selected aeration pressure combinations of 24h and 5kPa, 12h and 7kPa, 8h and 8kPa, 6h and 10kPa, 4h and 12kPa. The maximum surface and volume load removal of COD, ammonia nitrogen, total nitrogen achieved 19.2, 2.26, 2.53g/(m²·d) and 1.6, 0.19, 0.21g/(L·d), respectively, which showed significantly better performance of MABR than conventional biofilm and activated sludge processes. Oxygen transfer characterization showed that biofilm significantly enhanced the oxygen transfer rate (19.5~40.6gO₂/(m²·d)), oxygen transfer efficiency (30.9%~59.8%) and aeration efficiency (34.2~48.3kgO₂/kWh) of the investigated hollow fiber aeration membrane, implying the autonomous respiration of biofilm (i.e., automatically withdrawing the oxygen demand via aeration membrane to match the oxygen consumption caused by the influent load of ammonia nitrogen and COD). Thus, there is a significant potential for reducing pollution, carbon emission, energy consumption and cost for municipal wastewater treatment via MABR coupling intermittent aeration, synchronous coagulation, periodical detachment of excessive thick outer biofilm, adjustment of aeration flow and inlet/outlet pressure of membrane module to match the pollutants load.

Machine learning models, including multiple linear regression (MLR) and decision tree machine learning (LGB) algorithms, were used to predict the degradation efficiency of 57 organic pollutants in the Fenton process. Mechanistic interpretation of the models was performed by SHAP method to identify the key factors affecting the degradation efficiency. The results showed that the LGB model (R²_adj = 0.969, Q²_LOO = 0.925, R²_ext = 0.844) outperformed the MLR model (R²_adj = 0.831, Q²_LOO = 0.802, R²_ext = 0.861) in terms of prediction accuracy. The SHAP analysis revealed that temperature, molecular three-dimensional structure, and atomic ionization capacity were the main factors affecting the degradation efficiency. This study provides a scientific basis for optimizing the operating conditions of the Fenton process and enhancing the degradation efficiency, which is of great significance in guiding the research and practice in the field of water treatment.

Compared with the side-stream phosphorus recovery process based on enhanced biological phosphorus removal, biofilm phosphorus enrichment-recovery process has great application potential in the field of wastewater resource recovery due to the advantages of high phosphorus enrichment effect and phosphorus recovery rate. Enrichment and cultivation of biofilm predominated by phosphate-accumulating bacteria is the key to the operation of the process. However, the culture of phosphate-accumulating biofilms is affected by multiple factors, resulting in slow biofilm formation. Therefore, in order to realize the rapid cultivation of phosphate-accumulating biofilm, the operation control conditions, environmental influencing factors and formation mechanism of phosphate-accumulating biofilm was summarized in this paper. It was found that the aerobic aeration volume, sludge discharge time, as well as the type and concentration of carbon source are the key control conditions for the cultivation of phosphate-accumulating biofilm. The research direction for further achieving the rapid culture of phosphate-accumulating biofilm was prospected, with the expectation of providing a theoretical basis for the rapid start-up of phosphate-accumulating biofilm reactor.

Targeting the challenges in organic micropollutants (OMPs) detection and biotoxicity assessment, this study systematically evaluated four water pretreatment approaches and seven activated elution solvent combinations to improve the enrichment efficiency of residual organic matter in reclaimed water. The optimized procedure comprised: acidification to pH 2.5 with 5% (V/V) methanol addition; sequential SPE using HLB (500mg/6mL) and LC-18 (500mg/6mL) cartridges for broad-spectrum retention; ternary elution with 10mL methanol, 10mL ethyl acetate, and hexane (1:1V/V) to achieve polarity-balanced desorption. The optimized approach achieved 88% dissolved organic carbon (DOC) recovery, representing a 1.3~15.9-fold enhancement in OMPs recovery across compounds with logK_ow values ranging from 1.8 to 5.7 compared to conventional methanol-based methods. Notably, the optimized protocol reduced the sample volume required to reach EC50 in acute toxicity assays by 4.4-fold. The optimized method developed in this study significantly enhanced detection sensitivity and precision.

When typical triphenylmethane dyes (crystal violet) and phenazine dyes (saffron T) were used as the research objects, the biotoxicity of dye wastewater was investigated before and after treatment using the Fe⁰/H₂O₂ process through the analysis in growth indicators (growth rate and inhibition rate), photosynthetic indicators (chlorophyll a, chlorophyll b, and carotenoid content), protein content, polysaccharide content, and antioxidant enzyme activity systems (superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA)) of Chlorella vulgaris (C.vulgaris). The results showed that with the extension of reaction time, the growth rate of C.vulgaris gradually decreased and its inhibition rate increased. The growth of C.vulgaris cells was significantly inhibited in raw dye wastewater. Compared with raw dye wastewater, chlorophyll-A content of C.vulgaris was increased by 22.01% in the effluent wastewater after treatment, and the contents of chlorophyll-B and carotenoid were decreased by 12.97% and 16.02%, respectively. The contents of SOD and CAT were increased by 15.13% and 12.5%, respectively, while the content of MDA was decreased by 23.97%, respectively. The protein content of C.vulgaris in raw dye wastewater was low, while its content was high in the effluent wastewater after treatment. Compared with raw dye wastewater, the content of polysaccharide in the effluent wastewater exhibited a decreasing trend. According to the toxicity prediction of algae using EPI Suite software, the toxicity of the intermediate product of crystal violet and saffron T degradation to fish, water flea and green algae was significantly reduced. Therefore, the biotoxicity of dye wastewater could be effectively reduced in the Fe⁰/H₂O₂ system.

The persulfate-based advanced oxidation process demonstrates significant advantages in the removal of refractory organic pollutants. However, traditional activation methods are associated with high energy consumption and the potential generation of secondary pollution, which restricts the widespread application of this technology. Based on the photosensitive properties of dissolved organic matter (DOM) in secondary effluent, a practical self-activation peroxymonosulfate (PMS) reaction system using solar radiation was established. Systematic investigations were conducted on the effects of different persulfate types, initial pH conditions, and common inorganic anions on PMS decomposition efficiency, accompanied by comprehensive characterization of physicochemical properties and structural transformations in DOM before and after the reaction. The results indicated that the all fractions of secondary effluent could effectively activate PMS, with the hydrophilic (HI) fraction exhibiting the most efficient activation, achieving a PMS decomposition rate of up to 26.7% under neutral conditions. During the decomposition process, reactive oxidative species generated from PMS interacted with DOM, leading to the gradual degradation of its aromatic structures and a reduction in molecular weight. The intensity of fluorescent substances, such as humic-like compounds, significantly decreased, while the proportions of lignin, lipids, tannins, and other compounds had notable changes. These observations indicated that the DOM in secondary effluent achieved self-degradation through effective activation of PMS. Humic-like compounds and lignin in secondary effluent DOM served as the primary electron donors. Upon excitation by sunlight, they transferred photogenerated electrons to PMS, thereby activating it and triggering the self-degradation of DOM. The self-catalytic system of using the DOM in actual secondary effluent in this study without the need for external catalysts, avoiding high energy consumption and secondary pollution.

SiO₂@nZVI@Fe₃O₄ composites were successfully synthesized by liquid-phase reduction and stőber hydrolysis. The microstructures and physical phase compositions of SiO₂@nZVI@Fe₃O₄ were analyzed by SEM-EDS, TEM, XRD, FTIR, VSM, and XPS. The degradation performance of azo dyes was investigated by using SiO₂@nZVI@Fe₃O₄ as a non-homogeneous catalyst combined with H₂O₂to construct a Fenton-like system. The results showed that the SiO₂ coating improved the dispersion and oxidation resistance of nZVI@Fe₃O₄, and it was able to enhance the generation of Fe²⁺ and HO· in the Fenton-like reaction system. Under the conditions of 25℃, pH 3, H₂O₂ concentration of 15mmol/L, and material dosage of 0.6g/L, the removal efficiency of Congo red, Orange II and Acid Black 210 reached 99.68 %、98.14 % and 99.35 %. The composite material could still remove more than 79% of the three pollutants after recycling for three times, which has good stable catalytic performance. The removal of azo dyes by SiO₂@nZVI@Fe₃O₄ combined with Fenton-like system was mainly through the reduction of nZVI and the oxidation of HO·, as demonstrated by reactive oxygen species quenching experiment and UV-visible spectral analysis.

Fe-modified/unmodified Carex meyeriana Kunth biochars were prepared at 300, 500, and 700℃. The degradation efficiencies of rhodamine B (RhB) in water by peracetic acid (PAA) were compared. The effects of reaction conditions (PAA concentration, Fe-KBC700 dosage, RhB concentration, pH, H₂O₂ concentration, co-existing anion and fulvic acid) on 700℃ iron-modified biochar (Fe-KBC700) were studied. The dominant active species, activation mechanism and degradation pathways of RhB were analyzed. High pyrolysis temperature and the introduction of Fe were beneficial to the improvement of biochars activation properties. Fe-KBC700/PAA system degraded 99.8% of RhB within 30min. Higher PAA concentration, Fe-KBC700dosage and lower RhB concentration were conducive to RhB degradation, while alkaline conditions and higher co-existing H₂O₂ concentration inhibit the reaction. Cl^-, SO₄^2-, and NO₃^- hardly affect the degradation of RhB, while HCO₃^- and fulvic acid could inhibit the reaction. The degradation of RhB was mainly due to the non-radical pathway. Singlet oxygen, electron transfer process and high-valent iron were detected in the reaction. The oxygen-containing functional groups and defects of Fe-KBC700 were the key reaction sites, and two degradation pathways of RhB were inferred. In addition, Fe-KBC700 could degrade 75.4% of RhB after 5 cycles. This study could provide a reference for the optimization of catalytic performance of biochars and the mechanism of activation of PAA by iron-modified biochar.

Multi-metal catalysts Mn-Cu-Co-Ce/TiO₂, Mn-Ce-Co/TiO₂, and Mn-Ce-Cu/TiO₂ were synthesized via the impregnation method. Among them, Mn-Cu-Co-Ce/TiO₂ was characterized before and after the reaction using BET, XPS, O₂-TPD, FT-IR, SEM-EDS, and XRD techniques. The catalytic performance of the catalysts for isopropanol degradation in a non-thermal plasma (NTP) synergistic system was investigated. The effects of initial concentration, gas flow rate, oxygen content, and catalyst water content on degradation efficiency were systematically analyzed. Organic byproducts generated during the degradation process were detected using gas chromatography-mass spectrometry (GC-MS), and the degradation mechanism under NTP conditions was explored. The results indicated that the NTP-assisted multi-metal catalyst system exhibited over 54% improvement in degradation efficiency compared to NTP alone, achieving a removal rate of 90.22%. CO₂ selectivity also increased by approximately 34%, reaching 63.97%. In the synergistic system, degradation efficiency was negatively correlated with initial concentration, gas flow rate, and catalyst water content, while it was positively correlated with voltage. Moreover, the formation of byproducts such as O₃was effectively suppressed. The degradation path of isopropyl alcohol may involve multiple aspects, including direct oxidation mineralization under the guidance of NTP, intermediate oxidation process, and deep redox reactions.

Solid phase extraction (SPE) is extensively utilized for the extraction of dissolved organic matter (DOM); nevertheless, the efficiency of SPE under specific conditions (employing formic acid as the acidifier, hydrophilic-lipophilic balance (HLB) as the sorbents, and methanol as the elution solvent) remains unclear. In this study, 13 refuse leachate samples, 10 effluent samples after leachate treatment, and 14 surrounding groundwater samples from 13 landfills were collected. The excitation and emission matrix was employed to analyze the stock solution, eluent, and permeate before and after SPE, enabling the evaluation of DOM enrichment and loss during the extraction process. The results indicated that this SPE method could effectively extract fulvic acids with short emission wavelengths from leachate and aromatic proteins from treated effluent and groundwater. However, but it exhibited low efficiency in recovering large humic acid molecules. This inefficiency might be attributed to the incapability of formic acid to effectively protonate these components. Parallel factor analysis indicated that the method preferentially extracted structurally simple tryptophan-like proteins, while its performance for humic acids was restricted. The SPE method involving formic acid acidification, HLB cartridge adsorption, and methanol elution effectively separates and extracts structurally simple and hydrophilic DOM. These results provide a valuable reference for further elucidating the characteristics of low-molecular-weight, hydrophilic chlorinated DOM.

A continuous baffle flow electrocatalytic oxidation device, using porous Ti₄O₇ anodes prepared through vacuum plasm spraying technology, was developed to achieve the effective degradation of sulfamethoxazole (SMX) in wastewater. The effects of operation conditions on SMX degradation efficiency were examined, the energy consumption and the stability of the system were assessed in the treatment of actual wastewater. The possible electrocatalytic degradation mechanism of SMX was also proposed. SMX removal efficiency, energy consumption, mineralization efficiency and mineralization current efficiency could reach at 82.0%, 13.1kWh/m³, 34.2% and 0.7%, respectively, at the initial SMX concentration of 10mg/L, Na₂SO₄ concentration of 5mmol/L, current density of 5mA/cm², and solution velocity of 27mL/min. The primary degradation mechanism of SMX was indirect oxidation, and the contribution efficiencies of ·OH and were 76.2% and 5.8%, respectively. The dominant degradation pathways were hydroxylation, N-S bond cleavage, oxidation and coupling reactions. The device exhibited good stability during the long-term treatment of both experimental and actual wastewaters, with SMX degradation efficiency, TOC removal efficiency, and COD removal efficiency in actual wastewater reaching 100%, 19.8%, and 72.2%, respectively. The electrocatalytic oxidation device effectively degraded SMX, and it also reduced the toxicity. Therefore, the continuous baffled flow electrocatalytic oxidation device based on the porous Ti₄O₇ electrode can effectively eliminate SMX from wastewater.

Surface water samples were collected from two municipally monitored sections of the Tuhai River in Liaocheng—Li Fengtao and Lao Nanzhen—and analyzed using a combination of spectroscopic techniques, including ultraviolet-visible (UV-Vis) absorption and three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy, supplemented by ultrafiltration fractionation and fluorescence-quenching experiments to comprehensively characterize dissolved organic matter (DOM). The study investigated seasonal variations in DOM composition across three molecular weight fractions (<0.7μm, 0.7μm~1kDa, and<1kDa) and explored the underlying mechanisms of DOM-Cu²⁺ complexation. The specific ultraviolet absorbance at 254nm (SUVA254) was significantly higher at Li Fengtao (0.33 ± 0.01) than at Lao Nanzhen (0.30 ± 0.01) (P<0.05), suggesting a higher proportion of smaller, non-aromatic molecules at the latter site. Parallel factor analysis (PARAFAC) of EEM data identified five fluorescent components, including three humic-like (C1, C2, C4) and two protein-like (C3, C5) substances, with humic-like constituents dominating at both locations. Total fluorescence intensity (F_max) was higher at Lao Nanzhen, and dissolved organic carbon (DOC) was primarily concentrated in the <1kDa fraction at both sites. Two-dimensional correlation spectroscopy (2D-COS) analysis demonstrated that humic-like components preferentially bound to Cu²⁺ in the unfractionated DOM samples from both locations. However, after ultrafiltration fractionation, the binding sequence shifted, with protein-like components becoming the dominant Cu²⁺-binding constituents. Furthermore, high-molecular-weight fractions (excluding C1 and C4) from both sites exhibited relatively strong metal-binding capacities, as evidenced by their conditional stability constants (logK_Cu:(3.08 ± 0.08) to (3.62 ± 0.02)).

In order to understand the current research status of fingerprinting technology and clarify its application and prospects in the field of solid waste, the Web of Science (WOS) core database: Science Citation Index Expanded (SCI-Expanded) was relied upon to retrieve and analyze relevant literature from 2010 to 2024. It was found that the number of publications indicates that fingerprinting technology still maintains a high level of research interest. The subject clustering analysis shows that its application is extensive and its research interest in the environmental field has also been high in recent years. Keyword clustering reveals that the research hotspots are concentrated in four aspects: Recognition, ChemoInformatics, Deep learning, and Model. Keyword co-occurrence analysis of literature in the field of solid waste shows that there are few studies on the use of fingerprinting technology for solid waste management, mainly focusing on the post-processing stage. Through literature research, the data acquisition technology, feature extraction technology, and feature presentation forms of fingerprinting were summarized, and the possibility of applying emerging technologies in the field of solid waste and future development prospects were proposed.

To explore the enhancement strategies for the methane production efficiency of anaerobic co-digestion systems by exogenous compound enzymes, corn stover and food waste were adopted as the mixed substrates. Subsequently, the combination and concentration of exogenous compound enzymes were optimized through batch experiments and the response surface methodology. In the single-factor experiment on lignin, the component and concentration range of the compound enzymes were screened. Moreover, 20groups of experiments with the concentrations of laccase, endo-β-1,4-glucanase and xylanase as variables were designed by means of the response surface methodology, and with the methane production promotion rate as the optimization objective. Based on the experimental data, a model was successfully established and variance analysis was carried out. The results showed that response surface analysis identified enzyme combinations within the ranges of laccase (1.5~4.0U/mL), xylanase (12~20U/mL) and endo-β-1,4-glucanase (50~85U/mL), which could achieve a high methane production promotion rate, was finally determined as the appropriate component of the compound enzyme. The continuous flow test validated the efficacy of the composite enzyme, indicating that the addition of the compound enzyme promoted the proliferation of hydrolases and aceticlastic methanogens, released lignin, cellulase and anaerobic digestion enzymes with higher activities, and thus increased the methane production rate of the anaerobic co-digestion system by 19.5%.

Red mud (RM) was selected as the Fe source and orange peel (OP, pH=3.0~4.9) as the carbon source, RM@OPB composite was prepared through impregnation-pyrolysis method. The regulation of red mud alkalinity by orange peel and the influencing factors were analyzed. The catalytic performance of RM@OPB in activating PMS for IPM degradation was investigated as well. The mechanism of IPM degradation in the RM@OPB/PMS system was further explored through the combination of HPLC/MS analysis, active species quenching experiments, fluorescence spectroscopy, electron paramagnetic resonance (EPR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) of the pre-post-reaction of RM@OPB. Finally, the ecological toxicity of IPM and its intermediates was predicted using the Ecological Structure Activity Relationships (ECOSAR) software. The results demonstrated that orange peel co-impregnation effectively regulated the alkalinity of red mud, with the leachate pH decreasing from 11.0 to 7.27, at impregnation time and m_RM: m_OP of 24h and 1:2.5, respectively. During the pyrolysis, reductive gases generated from orange peel facilitated the transformation of Fe₂O₃ in RM into Fe₃O₄ and Fe⁰, magnetic RM@OPB materials was manufactured. Notably, RM@OPB-800exhibited effective catalytic performance for IPM degradation, with the degradation of 8mg/L IPM achieving 96.5% in 60min (k=0.065min^-1), under the experimental conditions of 0.5g/L RM@OPB-800, 1.0mmol/L PMS, and initial pH=6.7, respectively. Singlet oxygen (¹O₂) was identified as the dominant reactive species in the RM@OPB-800/PMS system. IPM degraded mainly through side-chain amide hydrolysis and oxidation, dehydrogenation, deiodination, and hydroxyl addition, with 12intermediates generated. ECOSAR analysis confirmed no highly toxic intermediates were formed. The findings can provide some critical insights into the resource utilization of red mud.

Food waste with different ratios of meat, fruits and vegetables was stored at 10~25℃ and 50% relative humidity for 48h in an environmental climate simulator to monitor the emission patterns of odors, identify the major odors, and explore the odors prevention and control strategies for the storage of household food waste in the community. The main odors from the short-term storage of household food waste were monitored to include the oxygenated compounds acetaldehyde and ethanol (combined odor contribution of 0.8% to 99.6%), sulfur-containing compounds (methyl sulfide, methyl mercaptan, and dimethyldisulfide), the alkanes 2-methylbutane and pentane, and α-pinene. The proportion of fruits and vegetables and meat significantly affected the intensity and relative composition of the odor emissions (differences between groups < 0.05). These two types of substances inhibited the decomposition of C-containing organic substances such as effective saccharides in food waste, but promoted the conversion of sulfur-containing organic substances to a certain extent, thus facilitating the formation and release of acetaldehyde and the three types of sulfur-containing compounds that had a greater impact on the odors, and the 48% FV (Fruit and Vegetable, hereinafter the same)-20.2% M (Meat, hereinafter the same) and 67% FV-3.6% M group rich in meat or fruits and vegetables were stored for 12~48h, and the theoretical odor concentration reached 38.7~68.1 and 83.7~205.3kg^-1 HFW (Household Food Waste, hereinafter the same) respectively, which were 5.5~9.4 times and 12.4~29.5 times higher than that of the food waste of 56% FV-4.9% M group under the same storage conditions. For the scenario of the community's multi-site unorganized emission of odorous air, the odor prevention and control can be performed according to the source and source of the odor release. Odor prevention and control can be carried out in accordance with the joint idea of source reduction, propagation prevention and control, and end reduction and purification.

A heavy soda saline soil was seleeted and rice was cultivated rice by potting method without applying organic fertilizers as a blank control (CK) to study the effects of application of common organic fertilizer (M0), 1% biochar loaded nano Fe₃O₄ (BC-Fe₃O₄ NPs) added composted organic fertilizer (M1) and 1% biochar loaded iron nanoparticles (BC-FeNPs) added composted organic fertilizer (M2) on the effects of soil physicochemical properties, nutrient effectiveness, enzyme activity and bacterial community changes. The results showed that the soluble salt content was significantly reduced by 23.31% (P<0.05) in M2treatment compared with M0. Compared with M0, the application of iron-rich organic fertilizer increased the total organic carbon content of soda saline soil by 4.95%. Compared with M0, the application of M2 significantly increased the content of Fe-bound organic carbon (Fe-OC) by 66.92%. Compared with CK, organic fertilizers increased soil quick-acting potassium and quick-acting phosphorus contents by 262.51%~521.28% and 222.99%~311.85%, respectively. Compared with M0, M2 treatment significantly increased the activities of sucrase, catalase and alkaline phosphatase, as well as the abundance and diversity of soil bacterial communities, and the relative abundance of Aspergillus, Bacteroidetes and Actinobacteria in the soil. The relative abundance of the above bacterial phyla was positively correlated with the fast-acting nutrient content of saline soil. Therefore, 1% BC-FeNPs composted organic fertilizer can significantly reduce soil soluble salt content, significantly increase total organic carbon content by promoting Fe-OC formation, and increase the abundance and diversity of bacterial communities, which is conducive to the fertilization of heavy soda saline soils.

The present study focused on the oxidative fixation of As(Ⅲ) by Fe(Ⅱ)-containing minerals in coordination with low molecular weight organic acids (LMWOA) (such as oxalic acid (OA), citric acid (CA), gallic acid (GA)) to generate reactive oxygen species (ROS). Siderite (FeCO₃) was utilized as the test mineral to investigate the capacity of FeCO₃-LMWOA complexes in adsorbed and co-precipitated states for As(Ⅲ) oxidation, and to analyze the generation of hydroxyl radicals (·OH) and the morphological changes of Fe during the oxidation process, as well as the effects of radical quenchers and C/Fe molar ratio on As(Ⅲ) oxidation and As(T) immobilization. The results demonstrated that adding 0.05~0.5mmol/L LMWOA enhanced the oxidation of As(Ⅲ) by siderite, with the order of GA>CA>OA, and the removal rate of As(Ⅲ) in the presence of GA was up to 80%. For the adsorbed and co-precipitated complexes, the oxidative capacity was enhanced by increasing C/Fe, and the co-precipitated FeCO₃-CA complex exhibited the highest removal efficiency of As(Ⅲ), reaching 92.1%. The free radical quencher methanol and NBT exhibited obvious inhibition on As(Ⅲ) oxidation, which proved that the main active substances for oxidizing As(Ⅲ) were and ·OH. The ability of different LMWOA to compete with As(Ⅲ) for ·OH was different, among which the co-precipitated FeCO₃-GA complex had the highest OC mineralization rate of 72.2%, and the main reason for the OC loss was the oxidation by ·OH. SEM and XRD analyses showed that siderite was transformed to hematite after reaction. This study not only reveals the synergistic mechanism between Fe(II)-containing minerals and LMWOA in As(Ⅲ) oxidation, but also provides new perspectives and strategies for the environmental management of arsenic pollution.

From the perspective of water quality-algae coupling, this study investigates the evolution of water quality and algal responses in the upper Xin'an River Basin in Anhui Province from August 2022 to April 2023. Multivariate statistical analyses identified the key drivers of water quality changes, and the relationships between water quality characteristics and algal indicators were explored. A composite algal indicator was developed to serve as an indicator of water ecological health, which includes [algal turbidity (AT) and algal dominance index (ADI)], elucidating its mechanisms in water quality assessment. Furthermore, a conceptual model integrating water quality and algal responses was proposed for comprehensive water quality identification. The results show that: (1) Water quality in the study area was primarily classified as Category Ⅲ (67.9%), with an average water quality index (WQI) of 81.61 (ranging from 55.42 to 90.83), signifying good quality overall. However, significant deterioration occurred between February and April 2023, with the WQI dropping to 76.09, highlighting the need for improved identification and protection measures. (2) Water temperature (WT), dissolved oxygen (DO), and nutrient concentrations were the primary factors driving water quality changes, with Spearman correlation coefficients reaching 0.72 (P≤0.01). (3) AT and ADI were effective composite indicators in rapidly identifying water quality degradation and ecosystem health. (4) The conceptual water quality identification model, constructed based on sensory characteristics, organic matter characteristics, and algal response, addresses the limitations of existing water quality standards, which often overlook biological indicators and degradation processes. These findings provide a scientific basis for identification and protecting the aquatic ecological environment of the Xin'an River Basin and offer insights into improving and innovating traditional monitoring systems.

Groundwater Dependent Ecosystems (GDEs) have played a vital role in maintaining ecological balance and providing ecological services, but they are facing increasingly severe threats under environmental changes. The identification and assessment of GDEs have been the basis for their monitoring, management, and protection. In this paper, the development, classification, delineation, and research methods for the identification and assessment of GDEs were reviewed. The framework of GDE identification and assessment models was summarized. The application of geospatial technologies, with GIS as a typical tool, and remote-sensing data provided by Landsat, Sentinel, MODIS, etc., in the identification of GDEs was explored. The current research limitations and future directions were put forward. The research on the identification and assessment of GDEs has evolved from using single determination methods, such as water level monitoring and isotopic analysis, to a comprehensive approach that integrates multiple data sources, including hydrogeological data, ecological indicators, and meteorological data. The representation of results has also shifted from traditional classification algorithms to the use of machine-learning-coupled algorithms, such as random forest models. However, how to accurately identify the spatial distribution of GDEs, precisely monitor their dynamic changes, and improve adaptive management strategies remain urgent issues to be resolved. In the future, theoretical innovation in the methodological system for GDE identification and assessment should be promoted. Innovation in methods should be achieved by integrating multi-source data, and technological innovation should be realized by exploring the application of deep-learning algorithms and the integration of artificial intelligence, so as to enhance the management level and efficiency of protection and restoration of GDEs.

In this study, microcosm experiment containing Vallisneria spiralis and La-modified attapulgite (LMA) was conducted to investigate the role of submerged macrophytes roots in controlling sediment phosphorus (P) release through the combined application of submerged macrophytes and La-modified clay. The dynamic variations of rhizosphere P and microenvironment were systematically analyzed using diffusive gradients in thin films (DGT), high-resolution dialysis (HR-Peeper), and 16S rRNA amplicon sequencing techniques. The results showed that the combined application of LMA and Vallisneria spiralis reduced the concentrations of soluble reactive P (SRP), DGT-labile P, and mobile forms of P (Mobile-P) in the sediment-porewater by 12.16% to 62.72%, 33.33% to 38.46%, and 3.66% to 10.53%, respectively, compared to the sole use of LMA. From day 7 to day 45, significant increases were observed in the total length, surface area, volume, root tip numbers and organic acid secretion of Vallisneria spiralis roots. Root-release oxygen enhanced the dissolved oxygen concentration and oxygen penetration depth at the sediment-water interface by 1.16-fold and 3.42-fold, respectively, shifting the dominant rhizosphere microbial communities from P-solubilizing bacteria such as Thiobacillus to aerobic bacteria such as Sideroxydans. Mantel test and partial least squares path modeling (PL-PM) analysis further revealed that organic acids secreted by Vallisneria spiralis roots accelerated the mineralization of organic P in the sediment, thereby enhancing OP absorption and utilization by the roots. Additionally, root-released oxygen promoted the proliferation of iron-oxidizing bacteria, which continuously oxidizing Fe²⁺ to Fe³⁺ in the porewater. This process immobilized SRP in the form of iron-bound P (Fe-P), effectively inhibiting P release from the porewater. This study provides novel insights that deepen the understanding of the mechanisms through which La-modified clay and submerged macrophytes jointly regulate the release of endogenous P in eutrophic lakes.

In the circumstance of global change, studying the dynamic changes of vegetation and the factors that influence it holds immense practical significance to monitor the quality of the regional ecological environment and improve the structure and function of ecosystems. In this study, the Theil-Sen Median trend analysis along with Mann-Kendal was used to characterize the overall change trend of vegetation ecology across the Yangtze River Delta based on the vegetation ecological quality index (VEQI) time series data (2000~2023). Then, the coefficient variation method was utilized to evaluate the stability in VEQI from 2000 to 2023. The geographic detector model was used to explain the natural and human activities driving mechanism of VEQI change. The results demonstrate that: The overall VEQI values in the Yangtze River Delta area showed a stage upward trend, with an increasing rate of 0.29a^-1. The upward trends observed in the VEQI indicated an enhancement in the ecological environment of the investigation area; The area whose VEQI increased was much larger than the area whose VEQI decreased. The area with improved VEQI accounted for 82.61% of the total area while the vegetation degradation areas for only 15.04%. The VEQI of study area owned a better stability, with low and relatively low fluctuation areas accounting for 54.66% and 15.99% of the area, respectively. The VEQI spatial variation primarily affected by a range of variances in natural phenomena and human activities, whereas spatial heterogeneity was mainly driven by factors such as landform type, elevation and slope. The improvement in the explanatory power of anthropogenic factors for spatial heterogeneity when combined with natural factors was significant. The research results aim to offer guidance for the execution of vegetation restoration initiatives and the establishment of policies for the preservation of the ecological environment in the upstream region of the Yangtze River Delta.

Based on Landsat and socio-economic data in the Northeast region from 1990 to 2023, this paper analyses the spatio-temporal characteristics of arable land ecological security using ecological footprint and ecological carrying capacity indexes, and explores the influence mechanism using geographic weighting model. The result show that: The per capita arable land ecological footprint increased from 0.135hm² per person to 0.145hm² per person, the per capita arable land ecological capacity decreased from 0.115hm² per person to 0.095hm² per person, and the per capita arable land ecological deficit increased from 0.16hm² per person to 0.058hm² per person. Farmland yield indicators show a decreasing trend, while indicators of ecosystem pressure on arable land show an increasing trend, and overall ecological security tends to improve. The impacts of natural resource on arable land ecological security shows a decreasing trend, while geographical location, socio-economic and regional policies show an increasing trend. This study is of reference value for the rational use of arable land resources and the sustainable development of ecological security.

Based on land remote sensing monitoring data from 2000 to 2023, this study employed geospatial models to quantitatively analyze the spatiotemporal evolution of land use functions in the upper reaches of the Yangtze River Economic Belt. In addition, a targeted analysis was conducted on the key influencing factors. The results indicate a continuous increase in the area allocated to living functions, whereas areas associated with production and ecological functions have declined. The spatial distribution of production functions exhibits a distinct pattern of being higher in the north and lower in the south, with significant spatial clustering of high and low-value regions. The distribution of living functions alternates between high and low from north to south and decreases from surrounding plains toward mountainous areas. Ecological function levels are significantly correlated with topography and geomorphology, showing pronounced spatial differentiation. The primary influencing factors include both natural and socio~economic variables, among which population growth, economic development, agricultural technology, and agricultural efficiency collectively drive the spatiotemporal evolution of the "production-living-ecological" land use functions. The findings provide valuable insights for regional land use planning and coordinated development strategies.

To explore the hydrochemical characteristics and hydraulic connections of different aquifers in the northern mining area of the Zhungeer Coalfield, and to reveal the regional water circulation patterns under coal mining activities, a total of 39water samples were collected from different aquifers in the mining area. The hydrochemical characteristics, controlling factors, and hydraulic connection degrees were analyzed using methods such as Piper trilinear diagrams, Gibbs diagrams, ion ratio analysis, chloride-alkalinity index, factor analysis, and connectivity index. The results show that the water in the mining area is generally weakly alkaline. The main hydrochemical type of the Quaternary and Shiqianfeng Formation aquifers is HCO^--Ca type water, which is mainly influenced by silicate weathering and mining activities, with positive cation exchange occurring. The main hydrochemical type of the Zhidan Group aquifer is HCO₃-Ca type water, followed by HCO₃-Na and Cl-Ca types. Its sources are mainly influenced by the weathering dissolution of silicate rock minerals and the impacts of mining and agricultural activities, with positive cation exchange occurring. The main hydrochemical type of mine water is Cl-Ca type water, which is influenced by the weathering dissolution of silicate and evaporite minerals and mining activities, with reverse cation exchange occurring. The hydraulic connectivity indices between the Quaternary aquifer and the Zhidan Formation, and between the Zhidan Formation aquifer and the Shiqianfeng Formation are 27% and 20%, respectively, indicating the presence of hydraulic connections. The hydraulic connectivity index between the Shiqianfeng Formation aquifer and the mine water is 39%, indicating a weak hydraulic connection.

In this study, the rates of denitrification and anammox, as well as their contributions to nitrogen removal, were quantified using the ¹⁵N isotope labeling technique in the riparian zones and sediments of different sampling sections within the 3rd Drainage Ditch in Ningxia's saline-alkali region. By integrating metagenomic sequencing and quantitative PCR (qPCR) analysis of functional genes, the influences of physicochemical properties, functional gene abundances, and microbial community structures on nitrogen removal processes in these two matrixes were systematically investigated. The results revealed that denitrification rates (1.22~3.75μmol N₂/(kg·h) were significantly higher than anammox rates (0.16~0.48μmol N₂/(kg·h) in both riparian zones and sediments (P<0.05), contributing 83.91%~92.95% and 7.05%~16.09% to total nitrogen removal, respectively. This indicates that denitrification is the dominant nitrogen removal pathway in the studied drainage ditch system. Sediments exhibited significantly higher denitrification rates than riparian zones (P<0.05), while no significant difference in anammox rates was observed between the two zones (P>0.05). Regarding functional genes, the abundance of the denitrification gene nirK was significantly higher in riparian zones than in sediments (P<0.05), whereas the opposite trend was found for nirS. Notably, the combined abundances of denitrification genes (nirK + nirS) were significantly greater than those of anammox-related genes in both matrixes (P<0.05). Microbial community analysis showed that Nitrososphaera was the most dominant genus among nirK-type denitrifiers in riparian zones, while Dechloromonas dominated the nirS-type denitrifier community in sediments. Environmental factors regulated microbial activity by influencing the abundance and expression of functional genes, thereby driving nitrogen removal processes. Higher total organic carbon (TOC) content, more anaerobic micro-environments, and greater functional gene abundances in sediments were identified as core driving factors contributing to their significantly enhanced denitrification capacity compared to riparian zones.

To investigate the fungal community structure, diversity, and influencing factors in three habitats (surface water, sediment, and riparian soil) of the Qingshui River in Ningxia, 22 sampling sites were established along the river in 2022. Sampling was conducted during the three hydrological periods: the normal period (May), the wet season (July), and the dry season (December). High-throughput sequencing technology was employed in conjunction with environmental factor measurements and multivariate statistical analyses. The results showed that the α-diversity of fungi in surface water was lower than that in sediment. However, the community structure in surface water was more sensitive to hydrological periods. In contrast, the fungal communities in sediment and riparian soil showed higher similarity. The dominant phyla were Chytridiomycota, Ascomycota, and Basidiomycota, and Fungi_gen_Incertae_sedis and Fusarium were identified as the key dominant genera. Water temperature (WT), pH value, bicarbonate (HCO₃^-) and calcium (Ca²⁺) in surface water, pH value, conductivity (EC), available potassium (AK), total phosphorus (TP) in sediments, pH value, total dissolved solids (TDS), ammonia nitrogen (NH₃-N) in interstitial water, water-soluble fluorine (Ws-F), exchangeable calcium (Ex-Ca), total nitrogen (TN), TP in riparian soil had significant effects on fungal community. The changes of fungal indicator groups reflected the environmental characteristics of different hydrological periods: the accumulation of agricultural non-point source pollution in the normal period, the migration of organic pollutants in the wet season, and the accumulation of refractory organics and high saline-alkali environment in the dry season.

3C-SiC was synthesized via the sol-gel carbothermal reduction method, and BiVO₄/SiC composites were prepared using a hydrothermal approach. The Vis+BiVO₄/SiC+PMS system was constructed for the degradation of CIP. Under optimized conditions, 1.0-BiVO₄/SiC was added with a dosage of 300mg/L, PMS concentration of 2mmol/L, and initial pH of the reaction of 7—the system achieved a 93.63% CIP degradation rate within 40minutes, with the k of 0.05456min^-1. These values represented 3.34 times and 3.27 times enhancement compared to BiVO₄ and SiC, respectively. The catalyst was characterized by SEM, XRD, XPS, UV-Vis DRS and electrochemical workstation. The excellent photocatalytic performance of BiVO₄/SiC was attributed to the formation of a Z-scheme heterojunction, which could promote the separation of electron-hole pairs while maintaining the high redox activity of the catalyst. Therefore, the Z-Scheme heterojunction formed by BiVO₄/SiC could effectively promote the activation of PMS and generate more active species, thus accelerating the degradation process of CIP. The active species in the system were identified as h⁺、¹O₂、·O₂^-、·OH、SO₄·^--- through the free radical quenching experiment. The efficient degradation of CIP was realized through the interaction of free radicals and non-free radicals. Notably, the catalyst exhibited excellent stability, retaining 89.49% of its initial degradation efficiency after five consecutive cycles. This study not only presents a novel strategy for PMS activation using photocatalysts but also demonstrates its successful application in antibiotic degradation, offering a promising approach for the remediation of organic pollutants in aquatic environments.

In this study, nitrate and ofloxacin(OFL) with high detection rate in groundwater were taken as target pollutants, and the effects of iron denitrification microorganism(M) with different inoculation dosage on the removal of nitrate and OFL by the dual materials of micro ZVI/FeS₂ system was investigated. Also, the influence of the major water chemical parameters, nitrate and OFL concentrations on the removal of nitrate and OFL in the coupled system(ZVI/FeS₂+M) was studied. In addition, the enhanced mechanisms for removing nitrate and OFL in the coupled system were explored. The results showed that the iron denitrification functional microorganisms could significantly enhance the removal of nitrate and OFL by ZVI/FeS₂. When the mass ratio and total dosage of ZVI/FeS₂ were 2:1 and 16g/L, respectively, and the inoculation amount of M was 5.81g/L, the nitrate in the ZVI/FeS₂+M reaction system was almost completely removed within 168h, and the removal rate of OFL was as high as 90.44%. Meanwhile, the ZVI/FeS₂+M system showed a good adaptability at different temperatures(10~30℃), nitrate concentrations(25~150mg/L), OFL concentrations(500ng/L~200ug/L) and the presence of coexisting ions. The intervention of microorganisms greatly delayed the passivation and oxidation of the ZVI surface, and at the same time, it could increase the dissolution of FeS₂ to produce FeS, Fe²⁺ and S^2-, which were all beneficial to the removal of pollutants. The removal of nitrate and OFL by ZVI/FeS₂+M after six cycles was still kept at 73.80% and 79.25%, which was still higher than that of the ZVI/FeS₂ (62.73% and 60.60%) in a one cycle experiment, indicating that the coupled system(ZVI/FeS₂+M) is a feasible method for remediating nitrate and antibiotic-containing groundwater.

Ultraviolet spectra, infrared spectra, and fluorescence spectroscopy with parallel factor analysis were used to explore the complexation heterogeneity and underlying mechanisms between tetracycline (TC) and dissolved organic matter (DOM) from hydrochars of three sources (i.e., sludge, chicken manure, and straw). Results showed that all three hydrochar DOM types exhibited high hydrophilicity and low aromaticity. Among these, straw-derived hydrochar DOM showed relatively higher aromaticity and larger molecular weight, whereas it had lower dissolved organic carbon (DOC) content and richer surface oxygen-containing groups. In contrast, sludge-derived hydrochar DOM possessed the highest DOC content but the lowest aromaticity and molecular weight. The fluorescence quenching of the three hydrochar DOMs by TC was static quenching. Sludge- and chicken manure-derived hydrochar DOMs showed significant quenching effects. The complexation constants (lgK) ranged from 4.48to 5.81 for sludge-derived hydrochar DOM and from 5.94 to 6.33 for chicken manure-derived hydrochar DOM, with corresponding capacities (f) of 0.21~0.40 and 0.14~0.46, respectively. Further analysis indicated that TC tended to quench the protein-like components in hydrochar DOM. The chicken manure-derived hydrochar DOM exhibited the strongest binding affinity with the protein-like component (C4), with the highest lgK of 6.33 and f of 0.46. The complexation effects between different source-derived hydrochar DOMs with TC varied, influencing the environmental occurrence, migration, and bioavailability of TC.

Aiming at the characteristics of complex sources and scattered emissions of antibiotics, a method for estimating antibiotic emissions was established. Based on the population and the number of livestock and poultry in the basin, the antibiotic emissions in different regions were obtained by combining the consumption coefficients of different organisms and the sewage treatment rate. Using the emission loads as the input data, the semi-distributed hydrological model-SWAT model was established to simulate the ciprofloxacin (CFX) and sulfamethazine (SMZ) in the middle and upper reaches of the Huaihe River. The results showed that the livestock breeding scale, regional population, sewage treatment capacity and large-scale management measures are the main influencing factors of antibiotic emissions in each city. The results of model validation showed that the simulated concentrations of CFX and SMZ are basically in the same order of magnitude as the monitoring values, with the good accuracy. In summer, the concentrations of CFX in the main channels of Huaihe River were almost all lower than 7.26ng/L. And in winter, the concentrations of CFX in the main channels of Huaihe River almost all were lower than 190.3ng/L. In summer, the concentrations of SMZ in the main channels of Huaihe River almost all were lower than 8.7ng/L, while in winter, the concentrations of SMZ in the main channels of Huaihe River almost all were lower than 38.11ng/L.

Based on confirming that the linear perfluorohexanesulfonate (L-PFHxS) could be degraded and defluorinated in a biomimetic system, the degradation products of isotope-labelled (¹³C) L-PFHxS (MPFHxS) were qualitatively analyzed, and the degradation mechanisms of L-PFHxS were then clarified. Two ¹³C-labeled perfluorocarboxylates (PFCAs, i.e. ¹³C₃-perfluorohexanoate and ¹³C₃-perfluorononanoate), eight native PFCAs (perfluorocarbon chain length ranged from C1 to C8), and seven native perfluoroalkylsulfonates (PFSAs, perfluorocarbon chain length ranging from C3 to C8, including linear and branched PFHxS), had been identified as the biomimetic degradation products of MPFHxS. The degradation pathways of L-PFHxS were proposed as follows: L-PFHxS were firstly reduced to C₆F₁₃· radical by cleavage of C-S bond, and then transformed to perfluorohexanoate through a series of hydrolysis. C₆F₁₃· radical or/and L-PFHxS were further reduced to form C_nF_2n+1· (n = 1, 2or 3) radicals, and these radicals were chain-lengthened by stepwise addition of 0 ~ 2C₃F₆ moieties and eventually transformed to various degradation products with different perfluorocarbon chain length via a series of hydrolysis (PFCAs) or combination reaction with sulfonyl hydroxide radical (PFSAs).

This study investigated the colonization process of ammonia-oxidizing microorganisms (AOMs) on five common types of microplastics (MPs) as well as the potential nitrification niches of MPs in water supply systems, with the methods of biofilm simulation reactors, physicochemical characterization of MPs and microbiological analysis techniques. The results indicated that chlorination and microbial colonization led to an increase in the crystallinity of microplastics and the formation of hydrophilic groups such as carbonyl and hydroxyl moieties. The abundances of amoA genes of AOMs on microplastics ranged from (1.54±0.02) × 10 to (3.07±0.64) × 10¹ copies/g. Comammox was predominant on most of the microplastics. Ammonia-oxidizing archaea (AOA), which was highly chlorine-resistant, was found to be predominant on the MPs only after chlorination for 42days. The total abundance of AOMs exhibited a positive correlation with microplastic crystallinity on unchlorinated microplastics, which was particularly obvious on higher intrinsic crystallinity MPs, ^i.e., polyethylene (PE) and polypropylene (PP). However, this correlation was not observed after chlorination treatment. Diversity analysis of AOMs colonizing on microplastics revealed that AOA on unchlorinated MPs were more closely related to soil-derived AOA. On the contrary, AOA on chlorinated MPs was more closely to aquatic AOA.

To explore the mechanisms by which gut microbiota dysbiosis influences the health effects of microplastics (MPs), a systematic search was conducted across five English-language databases (PubMed, Embase, Scopus, Cochrane, and Web of Science) and three Chinese-language databases (CNKI, Wanfang Data, and China Biomedical Literature Database). Studies addressing gut microbiota-mediated health effects of MPs exposure in mice and rats were identified and reviewed. A total of 27 studies met the inclusion criteria. The animal models used were primarily C57BL/6 mice, aged between 4 and 12 weeks, mainly male. The MPs used were mainly polystyrene, with particle sizes ranging from 0.05~53μm. The primary exposure routes were oral gavage and free drinking water, with exposure durations ranging from 3 to 13 weeks. Microbial community analysis was primarily performed using 16S rRNA gene sequencing. The studies investigated gut microbiota on harm through the gut-organ axis (including the liver, brain, testes, bone marrow, and lungs) and the gut-function axis (encompassing immune and metabolic functions). Intestinal microflora mediates the damage of MPs to mice through various metabolic pathways (such as amino acids and lipids) and signaling pathways (including TLR 2-Myd 88-NF-κB and intestinal microflora -HIF 1α/PTBP 1). Further clinical studies are warranted to better elucidate the potential mechanisms by which gut microbiota modulates the health effects of MPs exposure in humans.

In this study, the earthworm Eisenia fetida was exposed to soils contaminated with polylactic acid microplastics (PLA MPs, 0.5% w/w) and arsenite (As(Ⅲ), 40 or 100mg/kg) under single and co-exposure scenarios for 28 days. The responses of six selected biomarkers and the bioaccumulation levels of the two pollutants in earthworms were analyzed to evaluate the joint toxic effects and underlying mechanisms of PLA MPs and As(Ⅲ). Bioaccumulation results indicated that the bioaccumulation of As(Ⅲ) in co-exposure groups decreased by an average of 34.2% compared to the single As(Ⅲ) exposure groups. Biomarker analysis revealed significant oxidative stress responses in earthworms, which intensified with increasing exposure concentration and duration. The Integrated Biomarker Response index (IBR) was used to quantify the integrated toxic effects of multiple biomarkers, showing a significant dose-effect relationship in both single and co-exposure groups. Notably, the IBR values in co-exposure groups were reduced by an average of 28.8% compared to those in single As(Ⅲ) exposure groups. Joint toxicity evaluation indicated antagonistic interactions between PLA MPs and As(Ⅲ) at both arsenic exposure levels. These findings systematically elucidate the toxicological effects and potential mechanisms of PLA MPs and As co-contamination in earthworms, providing scientific evidence for ecological risk assessment of such combined toxicity.

A field survey was conducted in the East China Sea in autumn 2023 to study the distributions of carbon monoxide (CO) concentration, estimate the sea-to-air fluxes, and measure the microbial consumption and dark production rates of CO in the surface seawater. The results showed that atmospheric CO mixing ratios of the East China Sea ranged from 61.15 to 234.26 ppbv, with an average of (98.47 ± 49.64) ppbv. A headspace analysis system was used to determine CO. The concentrations of CO in the surface seawater ranged from 0.20 to 1.63 nmol/L, with an average of (0.63 ± 0.71) nmol/L. The CO concentrations exhibited noticeable daily variations across different water layers, with a maximum at noon and a minimum around dawn. The results of vertical distributions showed that the CO concentrations decreased gradually with the increase of depth. The sea-to-air fluxes of CO ranged from 0.45 to 5.66μmol/(m²·d), with an average of (2.11 ± 2.89) μmol/(m²·d). The results of sea-to-air fluxes estimation showed that the East China Sea was a source of atmospheric CO. The microbial consumption rate constants of CO in the surface seawater ranged from 0.16 to 0.33/h, with an average of (0.22 ± 0.07)/h. The consumption process showed the characteristics of first-order reaction. Dark production rates varied from 0.023 to 0.20nmol/(L·h), with an average of (0.12 ± 0.14) nmol/(L·h). The concentrations of CO increased linearly with the increase of time. This survey complements the source-sink processes of CO in the East China Sea, and contributes to a further understanding of the CO biogeochemical processes and its climatic effect in the continental shelf sea area.

In this paper, an oil field in Northern Jiangsu Province is selected as the research object, and a multiphase flow reaction migration model CO₂-DSMRT for CO₂ displacement and storage is constructed to describe the transformation and fate of supercritical state/gas phase, dissolved water phase, dissolved oil phase and mineral phase CO₂ on a century scale. The sensitive parameters affecting the prediction results of the model are identified by Sobol method. Furthermore, PSO-LSSVM method was used to establish an alternative model to characterize the mapping relationship between sensitive parameter input and CO₂ multiphase output results, and Monte Carlo stochastic simulation was carried out to quantify the uncertainty of the model. The results show that after 100 years of CO₂ injection into the oil-water mixed layer, the gas phase CO₂ accounts for 61.2%, the oil-soluble phase CO₂ accounts for 17.8%, the water-soluble phase CO₂ accounts for 11.2%, and the mineral phase CO₂ accounts for 9.8%. The most sensitive parameter of co₂-dsmrt model to oil production is permeability, and the most sensitive parameter to reservoir CO₂ storage is porosity. The production investment ratio of CO₂ storage capacity and oil production under different confidence levels is significantly different. P10scenario is suitable for storage priority strategy, P50 scenario can achieve the balance between storage and economic benefits, and P90 scenario is more suitable for production optimization strategy.

The three-dimensional carbon footprint of resource-based cities in the Yellow River Basin was measured, and their configuration paths of carbon reduction and footprint minimization were clarified through the three-dimensional carbon footprint model, the TOE framework, and fuzzy-set qualitative comparative analysis. It was found that during the study period, the average carbon footprint of resource-based cities in the Yellow River Basin exhibited a fluctuating downward trend, characterized by "continuous decline-slight rebound-fluctuating decline". The number of high-carbon footprint cities significantly decreased, and there were significant differences in the carbon footprint of resource-based cities in the upper, middle, and lower reaches, which were arranged in the order of "upper reaches < lower reaches < middle reaches". The carbon reduction and footprint minimization paths of resource-based cities in the Yellow River Basin could be summarized into three types: the "technology-structure dominant" path covering 44% of the cities, the "organization dominant" path covering 50% of the cities, and the "environment dominant" path covering 37% of the cities. Based on the above conclusions, it was suggested that a global perspective should be maintained to continuously monitor the carbon footprint values of resource-based cities in the Yellow River Basin, and a combination of measures should be taken to reduce the carbon footprint of these cities based on the configuration effects.

Based on the simple data of 261 cities from 2010 to 2020, the impact and mechanism of the policy of industrial transformation and upgrading demonstration zones on urban air quality were studied using the difference in differences method. It was found that the policy of industrial transformation and upgrading demonstration zones significantly improved the air quality of the demonstration zone cities: during the sample period, the concentration of PM_2.5 in the demonstration zone cities was reduced by an average of 3.238μg/m³, which accounted for approximately 7.711% of the average PM_2.5 concentration in the demonstration zone cities before the policy was implemented. This conclusion remained valid after robustness tests such as parallel trend testing, placebo testing, and the PSM-DID method. This conclusion remained valid after robustness tests such as parallel trend testing, placebo testing, and the PSM-DID method. Mechanism analysis revealed that the policy of demonstration zones mainly improved urban air quality by promoting the optimization of urban industrial structure and strengthening environmental regulations. Heterogeneity analysis found that, compared with resource-based cities, eastern and northern regions, the improvement effect of demonstration zone policies on urban air quality was more significant in old industrial cities, composite cities, central and western regions, and southern regions. The moderation effect analysis revealed that Chinese-style Decentralization had a moderating effect between the construction of demonstration zones and the improvement of air quality: compared with cluster-style demonstration zones and those that only received a qualified evaluation in the annual assessment, single-style demonstration zones and those that received excellent and good evaluations might have a more significant effect on air quality improvement.

This study employs a dual approach, utilizing both normalized carbon emission equivalents and eco-efficiency indicators based on data envelopment analysis (DEA), to evaluate633WWTPs within the Yangtze River Economic Belt. The mean eco-efficiency index was found to be 0.492. The eco-efficiency of WWTPs in the Yangtze River Economic Belt is significantly influenced by scale effects: mean index are 0.440 for plants with treatment scale ≤10,000m³/d, 0.507 for 10,000~100,000m³/d, and 0.729 for >100,000m³/d; notable differences in eco-efficiency exist across various regions and treatment processes: with sequencing batch reactors and continuously stirred tank reactors exhibit higher mean eco-efficiency index (0.569) than plug-flow processes (0.473). Additionally, as the BOD₅ concentration of influent in WWTPs increases, their eco-efficiency index rises but then declines. Moreover, advanced treatment processes exacerbate the environmental impact of wastewater treatment systems, WWTPs meeting Grade A discharge standards have a mean eco-efficiency index of 0.483, compared to 0.535 for Grade B-compliant plants.

This study takes the urban agglomeration on the northern slope of the Tianshan in Xinjiang as the research area. The ecosystem service supply and demand were analyzed through the InVEST model, ArcGIS software, and the Minimum Cumulative Resistance (MCR) model. The ecological security pattern were built according to the matching degree and coupling coordination of ecosystem service supply and demand. The results indicated that the ecosystem service supply and demand exhibited significant spatial heterogeneity. The mountainous and oases were the core output areas of ecosystem services, while the downtown areas with a highly concentrated population were the concentrated demand areas of ecosystem services. The information entropy and variation coefficient of ecosystem services were 1.48 and 0.41, respectively in 6,000m grid scale, and 1.44 and 0.43, respectively in town scale. 946 ecological sources with 10,003.70km² were confirmed by the comprehensive ecosystem service supply and demand ratio which were distributed in the central and western parts of urban agglomerations. 2,291 ecological corridors with a length of 22,191.89km were distributed as a net. 151 ecological nodes and 2,082km² obstacle points were distributed outside the urban center. 24 ecological coordination areas, 55 ecological conservation areas, 48 ecological improvement areas, 176 ecological control areas and 420 ecological restoration areas were classified through the ecosystem service supply and demand relationship in town scale. Ecological restoration projects, such as returning farmland to forests and restoring wetlands, should be prioritized in ecological restoration zones to alleviate ecological pressure.

This study measured the levels of Digital-Intelligence Integration (DII) and ecological resilience in cities within the Yellow River Basin from 2011 to 2022 using the entropy weight TOPSIS method and a coupling coordination model. The spatio-temporal evolution of DII was further analyzed. Building on these measurements, seemingly unrelated regression (SUR) and moderated mediation models were employed to investigate the effects, underlying mechanisms, and moderating factors influencing the relationship between DII and urban ecological resilience in the region. The results showed that the overall level of DII in the Yellow River Basin increased from 0.144 to 0.353 during the study period. By 2022, most cities had transitioned out of states of extreme and severe imbalance. A distinct spatial clustering pattern was observed for DII, with cluster centers predominantly located in the Shandong Peninsula and provincial capitals. The gap between these cluster centers and non-central cities was found to be widening. DII exerted a significantly positive overall effect on urban ecological resilience (regression coefficient = 0.197, p<0.01). However, its effect on the resistance dimension of ecological resilience was significantly negative (coefficient = -0.011, p<0.01), suggesting a potential weakening effect. Green innovation and public environmental concern acted as significant mediators. The regression coefficients of DII on green innovation and public environmental concern were 0.744 (p<0.01) and 0.345 (p<0.05), respectively. Financial development positively moderated these mediating roles, as the interaction terms between financial development and DII yielded significant coefficients of 0.122 and 0.146 (both p<0.01) for green innovation and public environmental concern, respectively. Heterogeneity analysis indicated that DII significantly enhanced urban ecological resilience only in downstream regions (coefficient=0.302, p<0.01), with no significant effects observed in upstream or midstream regions. Moreover, non-resource-based cities and those designated as big data comprehensive pilot zones exhibited stronger effects (coefficients = 0.235 and 0.285, respectively, both p<0.01) compared to other cities. These findings provide scientific support and policy references for optimizing urban ecological resilience in the Yellow River Basin in the era of digital intelligence.

The study focused on the spatiotemporal distribution characteristics of retired power batteries and critical metal resources in China. It used the LSTM neural network model to predict the sales volume of electric vehicles. It also estimated the stock of retired power batteries and critical metal resources by applying the Weibull distribution model, and further analyzed their spatial distribution characteristics. The research found that from 2012 to 2035, there were significant regional differences and spatial agglomeration in the cumulative retirement volume of power batteries and the cumulative stock of critical metal resources in China. Currently, Guangdong, Zhejiang, Shandong, Beijing, Shanghai, and Henan had the highest cumulative retirement volume of power batteries and the highest cumulative stock of critical metal resources, while Tibet, Qinghai, Ningxia, Heilongjiang, Xinjiang, and Inner Mongolia had the lowest. By 2035, Jiangsu was projected to replace Beijing as one of the six provinces with the highest cumulative retirement volume, with a cumulative retirement volume of 2.2546 million tons. Gansu was projected to replace Inner Mongolia as one of the provinces with the lowest cumulative retirement volume, with a cumulative retirement volume of 153,600 tons. In terms of spatial agglomeration, the high-high agglomeration area was found to be Jiangsu, while the low-low agglomeration areas included Xinjiang, Qinghai, Sichuan, Gansu, Inner Mongolia, and Jilin. It was projected that the scope of high-high agglomeration would expand further in the future (with Anhui and Shanghai being added), while the scope of low-low agglomeration would contract (with Sichuan no longer being part of this category). Regarding the distribution of processing capacities of the white-listed enterprises for the comprehensive utilization of retired power batteries, it was found that although China had an overall surplus in processing capacity, there was a spatial misalignment. It was anticipated that in the future, the recycling and regeneration capacities in Shanghai, Jiangsu, Hebei, Guangxi, Tianjin, Guangdong, Zhejiang, Yunnan, and Henan would not be sufficient to meet their own demands, and it was necessary to further optimize the layout of recycling and processing capacities.