This paper employed the multi-regional input-output (MRIO) to clarify the spatial and temporal evolution of the embodied pollutant emission patterns in China's interprovincial trade in 2012, 2015, and 2017. The structural decomposition analysis (SDA) model was applied to identify the socio-economic factors affecting the changes in pollutant emissions. The results showed that the areas with net pollutant export gradually shifted from those which have developed economic on the east coast to those have rich resources in the northwest. Moreover, the gap between provinces in net imports and exports of pollutants decreased. For example, the gap in SO₂ from 2012 to 2017 reduced by 63%. In addition, the increase of final demand was the main driver of the increase of emissions, with an average contribution of up to 669% to the emissions of the four air pollutants. The optimization of the energy consumption structure and the reduction of energy consumption per unit of GDP effectively curbed the momentum of emissions increase. The average contribution of the energy consumption structure to the four pollutants decreased from -220.75% to -546.25%. Although the impact of production technologies is minor, its impact on emissions has shifted from a facilitating to a dampening effect. This study provides new insights for improving energy efficiency and developing a clean energy mix, which contributes to developing measures to mitigate demand-side pollutant emissions and coordinated regional trade policies.

This study established 4treatments, straw degradation microbial agent (MC), organic fertilizer (OF), MC+OF, and control check (CK), and conducted a 120 days straw returning experiment to analyze the impact of different treatments on straw decomposition rate, soil nutrients, and soil microecology. The results demonstrated that the MC+OF treatment significantly improved the straw returning rate, especially enhanced the lignin degradation of stubborn components in the straw. After 120 days, the MC+OF group showed significantly higher rates of hemicellulose, cellulose, lignin degradation, and strawweight loss compared with other treatments, with increases ranging from 2.87% to 11.78%, 3.20% to 10.59%, 6.00% to 32.97%, and 9.49% to 26.77% respectively (P<0.05). The total amount of humus reached 70.39g/kg, a 24.87% increase compared with the CK; additionally, soil organic carbon and dissolved organic carbon increased by 33.39% and 62.00%, respectively, from their initial levels, while soil total nutrients(nitrogen, phosphorus, potassium) increased relatively by 134.21mg/kg. The combination of microbial and organic fertilizers also enhanced the activity of invertase, urease, and neutral phosphatase in the soil. Moreover, microorganisms such as Aspergillus in the MC treatment became dominant genera during the straw returning process, induced a significant enrichment of indigenous microorganisms with lignocellulose degradation functions like Alcaligenes, Ensifer, and Brevundimonas. The combination of microbial and organic fertilizers decreased the total amount of pathogenic saprophytic fungi in the soil and improved soil quality. These results indicate the immense potential of MC+OF in accelerating the recycling and utilization of straw resources.

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”.

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.

Based on the second level sounding data and routine environmental meteorological monitoring data from four regions(Chengdu, Yibin, Dazhou, and Chongqing) of the Sichuan Basin, during the winter of 2014~2017, combined with Mie scattering liDAR detection data in Chengdu during the same period, the boundary layer structure was identified by atmospheric extinction coefficient profile, and the evolution characteristics and pollution effects of atmospheric boundary layer inversion during haze weather were investigated. The results indicated that: Surface Layer Inversion (SLI), Mixed Layer Inversion (MLI), and Aerosol Boundary Layer Inversion (ABI) represented the three fundamental forms of boundary layer inversion. They showed a gradually weakened trend from bottom up and mark spatial variation among different regions. With the evolution of haze events from the formation phase to the persistence phase, the frequency of the three-layer inversions significantly increased. In the process, the intensity and thickness of SLI gradually decreased. However, the intensity and thickness of MLI exhibited quite opposite trend. In the meantime, the base height of MLI also decreased. The intensity and thickness of ABI fluctuated all the time. The coexistence and co-evolution of SLI and MLI not only strongly inhibited the vertical dispersion of ground pollutants, but also contributed to the increased near-surface humidity, which in turn induced the accumulation of particulate matter at the surface and enhanced aerosol hygroscopic properties, thereby reducing ground-level visibility. The above results revealed complex evolutionary patterns of boundary layer inversion during haze episodes in the Sichuan Basin from a new perspective and lay the foundation for integrated studies on the tropospheric lower-level inversion.

Monitoring and obtaining observation data of atmospheric anomia is of great significance for further reducing fine particles pollution. The study uses satellite remotely sensed Infrared Atmospheric Sounding Interferometer (IASI) data to conduct research on the accounting method of atmospheric ammonia emission intensity and total ammonia in the Beijing-Tianjin-Hebei and surrounding areas, providing support for the remote sensing monitoring application of atmospheric ammonia and ammonia reduction.Spatial interpolation was performed on spatially discontinuous data to calculate the annual average emission intensity (YNH₃), seasonal average emission intensity (QNH₃), and monthly average emission intensity (MNH₃) of atmospheric ammonia, and to estimate the total amount of atmospheric ammonia (TNH₃). By doing so, the spatial distribution characteristics and temporal variation patterns of atmospheric ammonia in the study area were analyzed, and finally, the influencing factors of atmospheric ammonia emissions were further examined. The results showed that from 2014 to 2022, the daily average emission intensity of atmospheric ammonia in the study area was 7.99kg/km². The central part of the region was a high value area for YNH₃, and the five cities with low column concentrations and low increasing rates were mainly distributed in northern Hebei and southern Henan. The eight cities with low column concentrations but high increasing rates were distributed in southwestern Henan, central Hebei, and Jiaodong Peninsula. The nineteen cities with high column concentrations but low increasing rates and sixteen cities with high column concentrations and high increasing rates were distributed in the central region and the surrounding of the Bohai Sea. Over the past 9 years, both YNH₃ and TNH₃ have shown an increasing trend, with YNH₃ in the study area growing from 5.89kg/km² to 9.20kg/km², with a compound annual growth rate of 5.73%; TNH₃ increased from 1169kt to 1825kt. In terms of temporal distribution, QNH₃ exhibited periodic changes, with summer being the peak season for QNH₃ and July being the peak month for MNH₃. TNH₃ had a high correlation with arable land and population, and their spatial distributions were highly consistent with each other, indicating that farming and population are important influencing factors of ammonia emissions in the study area. Random Forest analysis showed that agricultural and living sources were the most significant reduction factors of ammonia emission. This study demonstrated that remote sensing monitoring of atmospheric ammonia can offer data support for air quality monitoring operations.

To control the addition of chlorine disinfectant in drinking water disinfection technology, and to combine the coagulation and disinfection units to reduce energy consumption, a quaternary ammonium chitosan-based flocculant (CTS-g-CHPTAC) with dual functions of flocculation and sterilization was developed. This flocculant effectively removes kaolin and Escherichia coli from wastewater. Material characterization results showed that CTS-g-CHPTAC had a higher cationicity (29.51%) and better water solubility. Flocculation performance tests indicated that the turbidity and bacterial removal rates of CTS-g-CHPTAC reached up to 98.5% and 99%, respectively, when dosages were 0.2mg/L and 2mg/L. Meanwhile, the removal rate was as high as 97% when the dosage of CTS-g-CHPTAC was only 1~1.6mg/L in the mixed simulated wastewater, and the removal rate of mixed pollutants was as high as 95% within the pH range of 5~11. It is speculated that CTS-g-CHPTAC's higher cationic content and rougher surface topography enhance charge neutralization, adsorption bridging, and net sweeping effects, leading to improved flocculation.Furthermore, CTS-g-CHPTAC has bactericidal function, which can interact with the cell wall and cell membrane of E. coli through the quaternary ammonium group on CHPTAC and the amino group on chitosan and kill E. coli.

In response to issues identified in the polycyclic aromatic hydrocarbons (PAHs) emission inventory for Guangdong Province—including time-lag, unclear source classification, and ambiguous emission trends—a refined PAHs emission factor library for anthropogenic sources was established through comprehensive literature research. A high-resolution, bottom-up PAHs emission inventory of 16PAH compounds for Guangdong Province covering 2006~2020 was developed using the emission factor method, providing insights into principal emission species, key sources, and the spatiotemporal evolution of emissions. The findings were as follows: From 2006 to 2020, anthropogenic PAHs emissions in Guangdong Province showed an overall decline of 45%, with the contribution of carcinogenic PAHs reducing from 60% to 29%. Naphthalene (Nap), benzo[g,h,i]perylene (Bghip), and phenanthrene(Phe) emerged as the primary PAH species, contributing on average 23%, 10%, and 9% to total PAHs emissions, respectively. As national standards for diesel vehicles and motorcycles tightened, yellow-label vehicles were eliminated, and policies like the prohibition on straw burning were enacted, the primary sources of PAHs emissions shifted from motorcycles, diesel vehicles, and biomass burning to industrial coal combustion, coking, and household combustion. Spatial analysis indicated that line-source emissions (primarily from motorcycles and diesel vehicles) decreased significantly, while point-source emissions from industrial sources increased across several regions. Considering population health risks and the need for targeted PAHs emission controls in densely populated areas, the study recommends enhanced regulation of PAHs from industrial coal combustion and coking industries. This study provides critical scientific support for Guangdong Province′s PAHs emission control strategies, with a focus on public health outcomes.

A photocatalytic membrane reaction process, integrating a CBM (gC₃N₄/BiOBr/MXene) photocatalyst and a polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane, was constructed using a phase inversion method. The addition of CBM was adjusted to optimize the membrane surface structure and properties, as well as to improve the hydrophilicity and permeability of the composite membrane. Tetracycline hydrochloride (TC-HCl), a common antibiotic drug, was used as the target pollutant in the dead-end process to assess the separation and fouling resistance capabilities. The optimally doped PVDF/CBM-0.6membrane achieved 92 % degradation of TC-HCl, in which the active species •O₂^- and h⁺ played a dominant role. The degradation efficiency remains above 85% after 5 cycles, proving its good recyclability. Thirteen degradation intermediates and potential degradation pathways were proposed, including hydroxylation, demethylation, deamination, benzene ring opening, and deamidation reactions. Continuous operation with bovine serum albumin (BSA) confirmed the ability of the process to alleviate irreversible membrane fouling by preventing pore blockage and pollutant adhesion, achieving an efficient membrane self-cleaning.Overall, the CBM/PVDF photocatalytic membrane proposed in this work has the potential to enhance the practical application of photocatalytic membrane reaction systems.

To investigate the impact of phosphorus input on phosphorus output in the Three Gorges Reservoir Area, this study utilized the Net Anthropogenic Phosphorus Input (NAPI) model and the improved Export Coefficient Model (ECM) to analyze the spatiotemporal characteristics of phosphorus input and output from 2006 to 2021, as well as their response relationship. The results showed that the annual NAPI value initially increased and then decreased, with a peak in 2015. The distribution of NAPI values exhibited spatial clustering among counties, with phosphorus fertilizers contributing the most to NAPI, averaging 64.42% annually. Total phosphorus (TP) output fluctuated around 2500 tons per year with a slowly increasing trend, and the areas with high TP values shifted from the northeastern to the southwestern parts of the reservoir area. Dryland contributed the most to TP, with an annual average of 41.25%. There was a positive correlation between TP and NAPI, with the phosphorus input from human food and animal feed (P_im) having the greatest overall impact on TP, followed by non-food phosphorus input (P_nf) and phosphorus fertilizer input (P_fer). P_im was found to generate more TP per unit than P_nf and P_fer. The phosphorus output rate ranged from 1.18% to 2.26%, with an annual average of 1.78%. The proportion of P_im had the greatest influence on the phosphorus output rate, followed by the proportion of P_nf, with the output rate increasing as the proportions of P_im and P_nf increased. In contrast, the proportion of P_fer was negatively correlated with the phosphorus output rate. P_im posed the greatest threat to potential regional phosphorus pollution risks. This study provides scientific references for water environment management in the Three Gorges Reservoir Area.