By using Eisenia fetida as the test object, the growth and reproduction, cytochrome P450 (CYP) sub-enzymes activity, and small molecule metabolites were measured to investigate the metabolic toxicity of polyethylene microplastics with different particle sizes (small, 30~50µm; large, 125µm) at different concentrations (0.5, 2.5, 10, 20g/kg). The results showed that small particles of polyethylene were more likely to retain and accumulate in earthworms, and their harm to earthworms were greater. And large particle polyethylene microplastics could inhibit the reproduction of earthworms to some extent. The top twelve most important metabolites identified by metabolomics responded differently under the stress of different sizes of polyethylene, and the particle size of polyethylene had a significant effect on the toxic effect. The stress of small-size polyethylene with low concentrations (0.5, 2.5g/kg) had no significant effect on the CYP2B6 and CYP3A4 activities and the concentrations of important metabolites in earthworms; under the stress of small-size polyethylene with high concentrations (10, 20g/kg), the levels in seven important metabolites (L-formylkynurenine, androstanedione, androstenedione, docosapentaenoic acid, (5Z, 8Z, 14Z) -11, 12-dihydroxyicosa-5, 8, 14-dienoic acid (11, 12-DHET), inositol, and all-trans-retinoic acid) significantly increased by 20.5% to 70.2% compared to the control. Small-size polyethylene could cause the inflammation and neuro-metabolic disorders in earthworms, and damage their osmotic regulation metabolism. The significant induction of CYP2B6 and CY2C9 activity revealed that earthworms had certain detoxification functions. Under the stress of large-size polyethylene with the concentration of 0.5~20g/kg, no significant change in the activities of CYP2B6 and CYP3A4 in earthworms in comparison to the control was observed. However, the levels in majority of important metabolites, including L-formylkynurenine, androstanedione, androstenedione, adenosine 3'-phosphate, inosine, and xanthine, were all significantly lower than the control by 20.0% to 77.3%, which suppressed the hormone production of the earthworms, thus affecting their reproduction and metabolism.

To investigate the seasonal variation and source of oxidative potential (OP) in atmospheric fine particulate matter (PM_2.5) in Xi’an, the mass normalized OP (OP^DTTm) was measured using the dithiothreitol (DTT) method, and the influence of chemical components of PM_2.5 on OP^DTTm was analyzed, and the contributions of different sources to OP^DTTm was quantified using a positive matrix factorization coupled with an artificial neural network multilayer perceptron (PMF-ANN-MLP) model. The findings revealed that OP^DTTm in Xi’an was highest during summer ((13.2 ± 5.4) pmol(min·µg)) and lowest in winter ((5.6 ± 2.7) pmol(min·µg)). Correlation analysis indicated that nitro-containing aromatic compounds and carboxylic acids have a significant impact on OP^DTTm, and the difference in molecular abundance was the main reason for the seasonal variation of OP^DTTm. Source apportionment showed that dust (26.7%), traffic (35.1%), secondary formation (23.2%), and biomass burning (24.5%) and coal combustion (25.8%) were the predominant contributors to OP^DTTm during spring, summer, autumn, and winter, respectively. These results provide a scientific foundation for developing effective air pollution control measures aimed at safeguarding public health.

This study focuses on the reciprocating vibration membrane bioreactor (VMBR) technology and has established a pilot-scale low energy consumption reciprocating membrane bioreactor (LEP-N-MBR) system to treat the A²/O effluent from wastewater treatment plants, with a treatment capacity of 350m³/d. The findings revealed that during the entire operation, the energy consumption of the vibration membrane was only 0.020 (kW·h)/m³, which significantly reduced the energy consumption of the MBR. At a sludge concentration (MLSS) of 3000mg/L, the removal rates for TN and COD were 53.78% and 61.76%, respectively, with an effluent NH₄⁺-N concentration of only 0.51mg/L. However, when the MLSS increased to 6000mg/L, the effluent NH₄⁺-N concentration increased to 2.07mg/L, and compared to when the MLSS was 3000mg/L, the membrane operation cycle was shortened by 33.3%. Batch testing indicated that the maximum ammonia oxidation rate and denitrification rate of the system's sludge were 3.65 and 5.55mg/(g·h), respectively. High-throughput sequencing indicated that under low-nutrient conditions, the reciprocating vibration membrane facilitated the release of organic matter on the membrane surface, which was then utilized by microorganisms such as Hyphomicrobium and norank_f__Microtrichaceae to enhance nitrogen removal efficiency through metabolic processes. The low-consumption and high-efficiency pilot LEP-N-MBR system can provide new technical perspectives and theoretical guidance for urban wastewater treatment plants, and assist in achieving the goals of “dual carbon”.

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

To prepare a highly efficient heterogeneous carbon-based magnetic catalyst with excellent solid-liquid separation properties and good stability for activating potassium peroxymonosulfate (PMS), this study employed Mn.Zn.FeO (MZF)magnetic nanoparticles (MNPs) as the magnetic core, and dopamine (DA) along with powdered activated carbon (PAC) was utilized to synthesize the magnetic nanocomposite MZF@PDA-PAC through a step-by-step deposition method. MZF@PDA-PAC was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and a vibrating sample magnetometer (VSM). The efficiency of MZF@PDA-PAC in activating PMS for the degradation of diclofenac sodium (DS) was investigated, along with the removal mechanism of DS and the activation mechanism of PMS by MZF@PDA-PAC. The results showed that MZF@PDA-PAC possessed a "core-shell" structure, which exhibited excellent dispersibility and solid-liquid separation performance in water. Both radical pathways (, HO· and ) and non-radical pathways (electron transfer) played important roles in DS removal in the MZF@PDA-PAC+PMS system, with DS and TOC removal efficiencies of 99.50% and 66.32%, respectively. MZF@PDA-PAC was shown to have high stability and good recyclability, which has broad application prospect in the degradation of refractory organic compounds.

Eight representative automobile manufacturing enterprises were investigated, and 109 samples of raw and auxiliary materials, including coatings and adhesives, were collected to determine reactive organic carbon (ROC) and to establish the source composition spectrum of ROC in automobile manufacturing industry. The maximum incremental reactivity (MIR) method and two-product parametric method were used to quantify the corresponding contributions of ROC to the generation of O₃ and SOA. The results showed that: ① The VOC contents in different types of raw and auxiliary materials varied considerably: the average ρ(VOCs)of water-based and solvent-based automotive coatings were 289.92 and 490.32g/L; the average ρ(VOCs) of water-based, bulk and solvent-based adhesives were 27.00, 27.50 and 196.67g/L, respectively; and the average ρ(VOCs) of water-based and solvent-based cleaning agents were 116.60 and 831.20g/L. ② The main components of water-based coatings were alcohol ethers and ether esters, esters and alcohols, the main components of solvent-based coatings were aromatic hydrocarbons, esters and alcohols, and the main components of both bulk and solvent-based adhesives were alkanes. ③ In water-based coatings, the mass proportions of various organics were SVOCs (36.03%), IVOCs (37.77%) and VOCs (26.21%). In solvent-based coatings, the mass proportions of various organics were IVOCs (4.59%) and VOCs (95.41%). In bulk adhesives, the main organics was VOCs (100%). In solvent-based adhesives, the mass proportions of various organics were IVOCs (2.64%) and VOCs (97.36%). ④ The OFP productions by water-based coatings, solvent-based coatings, bulk and solvent-based adhesives were 93.67, 2679.27, 25.82, and 41.82g O₃/(L raw materials), respectively, and the primary contributing species were diethylene glycol butyl ether (42.03%), 1,2,3-trimethylbenzene(28.29%), 2,2,4,6,6-pentamethylheptane (52.20%), and 2,2,4,6,6-pentamethylheptae (78.63%), respectively. ⑤ The SOA productions by water-based coatings, solvent-based coatings, bulk and solvent-based adhesives were 18.49, 16.70, 4.82, and 4.28g SOA/(L raw materials), respectively. The largest contributions to SOA formation were caused by IVOC and SVOC species in water-based coatings, yet the largest contributions to SOA formation were VOCs species in solvent-based coatings and adhesives. ⑥After adding the assessment of the contribution of IVOCs and SVOCs species to SOA generation in the study, it was found that SOA productions per unit volume of water-based coatings were higher than that for solvent-based coatings and adhesives, which showed that the effects of SVOCs and IVOCs in water-based coatings on the atmospheric environment should be taken into account in pollution prevention policies formulation.

To have explored the mechanism of the impact of MPs on the nitrogen metabolism function of water bodies, the study had conducted indoor simulation experiments from the perspective of microorganisms. Specifically, it had experimentally tested the impact of traditional polyethylene (PE) microplastics and biodegradable polylactic acid (PLA) microplastics at various concentrations (0, 1, 5, and 10mg/L) on total nitrogen (TN), ammonium (NH₄⁺-N), nitrite (NO₂^--N), and nitrate (NO₃^--N) levels. Furthermore, it had analyzed the effects on nitrogen-metabolizing microbial communities and their functional genes. The results had shown that both PE and PLA microplastics had contribute to nitrogen accumulation in water. PE microplastics increased TN concentrations by 53.77% to 94.76%, while PLA microplastics had caused an increase of 24.04% to 48.74% compared to the control. The impact on different nitrogen forms had varied according to the type and concentration of microplastics. Notably, PE microplastics had been negatively correlated with nitrogen-fixing bacteria, such as Cyanobacteria, whereas PLA microplastics had exhibited a positive correlation with bacteria involved in inorganic nitrogen processes, such as Actinobacteria. It had further shown that both PE and PLA microplastics had significantly affected genes responsible for nitrogen fixation, nitrate reduction, and denitrification. This research had highlightsed the complex effects of microplastics on nitrogen cycling in aquatic systems, with the same particle size but different types and concentrations of MPs leading to varied outcomes on microbial community structure and nitrogen metabolism functions.

This study estimated the initial volume mixing ratios of the ambient VOCs measured from 18 April to 31 July 2021 in Linfen, Shanxi Province, using a photochemical age-based parameterization method, and corrected photochemical loss effects.Positive matrix factorization (PMF) was used to conduct the initial-data source apportionment. The results showed that the average volume mixing ratio of total VOCs (TVOCs) during the study period was 17.1×10^-9. The average initial volume mixing ratio of TVOCs in the daytime was 27.2×10^-9, with chemical loss of 10.6×10^-9 and loss rate was approximately 39.0%. Compared with other VOC groups, alkenes had the highest loss rate (66.0%). The chemical losses of isoprene (3.16×10^-9), 1,3-butadiene (1.27×10^-9), and ethylene (1.19×10^-9) were higher than any other species. During the ozone pollution (OP) period, the chemical loss of TVOCs was 15.1×10^-9, which was 1.6times higher than during the non-ozone pollution (NOP) period. During the OP period, the loss rate of alkenes was the highest (81.7%) than the other VOC groups. The losses of isoprene, 1,3-butadiene, trans-2-butene, and trans-2-pentene were 5.05×10^-9, 1.85×10^-9, 1.59×10^-9, and 1.10×10^-9, respectively, substantially higher than any other species. The PMF apportioned results based on the initial volume mixing ratios (i.e., IC-PMF) showed that petrochemical-related enterprise emissions (36.4%), natural gas (17.2%), the mixed source of diesel vehicle emissions and solvent usage (12.9%), gasoline vehicle emissions (9.6%), liquefied petroleum gas (8.6%), biogenic emissions (8.6%), and combustion sources (6.7%) were the main contributors to the ambient VOCs in Linfen during the study period. Compared to the PMF apportioned results based on the observed volume mixing ratios (i.e., OC-PMF), the contribution of biogenic emissions was underestimated by 83.3%, which was substantially higher than those of other sources; followed by the mixed sources of diesel vehicle emissions and solvent usage (22.2%) and the petrochemical-related enterprise emissions (19.7%). Meanwhile, the IC-PMF results suggested that the sources with higher contributions during the OP period were the petrochemical-related enterprise emissions and biogenic emissions, accounting for 24.1% and 21.7%, respectively. According to the IC-PMF apportioned results, the estimated results using the ozone formation potential (OFP) model showed that petrochemical-related enterprise emissions was the highest contributor to the OFP, with the contribution of 50.7% to the total OFP, followed by biogenic emissions (24.8%) and the mixed source of diesel vehicle emissions and solvent usage (10.4%). The emission sources with higher contributions to the OFP during OP period were biogenic emissions and petrochemical-related enterprise emissions, reaching 52.6% and 27.8%, respectively.

Microplastics exhibited unique properties and possessed a wide distribution across various environments. The confluence served as a key point for the contamination of microplastics. At present, there was a lack of effective methods to reveal the motion characteristics and accumulation areas of microplastics at the confluence. The motion and fate of microplastics should be accurately captured at the confluence. The three-dimensional hydrodynamic-microplastic transport model for microplastics was established at the confluence. The transport mechanism and fate of microplastics were investigated under varying junction angles and flow ratios through the coupled CFD-DEM method. The results showed that (1) The low velocity zones, including the flow separation, flow stagnation, and downstream of the flow separation, would evolve into regions of microplastic accumulation. (2) Microplastics were primarily influenced by the vortex located in the flow separation, entering the vortex zone from the right bank of the mainstream and gradually forming an elliptical enrichment region. (3) The concentrations of microplastics in the center of the flow separation were positively correlated with the junction angles. (4) There was a linear negative correlation between the concentrations of microplastics and the flow ratios in the center of the flow separation, R²=0.9007. The number of microplastics in the flow separation exhibited a significant negative correlation with the flow ratio at the confluence. The findings of the study would advance the fundamental understanding of microplastic motion in confluences and establish a theoretical framework for precise prevention and control strategies against microplastic pollution.

The porous two-dimensional carbon nanosheets with high graphitization and defect sites, designated M-C and M-N, were successfully synthesized via molten salt-assisted pyrolysis of glucose, with oxysalts (K₂CO₃ or KNO₃) as additives, respectively. The oxysalts significantly enhanced the specific surface area of the carbon nanosheets. Particularly, KNO₃ promoted nitrogen doping in M-N, resulting in a maximum adsorption capacity for acid orange 7 (AO7) of 480.77mg/g, surpassing that of biochar (BC) from direct pyrolysis and M-BC from molten salt-assisted pyrolysis without oxysalts. The adsorption and catalytic degradation of AO7 removal over carbon materials exhibited a synergistic effect. The catalytic activity of M-N in peroxymonosulfate (PMS) activation was 22.64times that of M-BC and 33.48times that of BC. Additionally, the impact of nitrogen doping and other structural defects on the non-radical pathway-dominated catalytic processes was preliminarily assessed using density functional theory (DFT) calculations. This study indicates that oxysalts can significantly reduce the amount of molten salt required in the preparation of carbon nanosheets, and also provides theoretical guidance for developing bifunctional biomass-based carbon materials for highly efficient organic pollutants adsorption and PMS activation.