Hydrogen nanobubbles have shown great potential in various applications such as environmental remediation, energy fuel production, and medical applications. However, accurately determining the total hydrogen content in hydrogen nanobubble water has been a challenge, which affects the evaluation of nanobubble generator performance. To address this issue, a method using headspace gas chromatography was developed, which transferred hydrogen from the liquid phase to the gas phase by heating the headspace bottle to achieve gas-liquid equilibrium, and then determined the total hydrogen content in hydrogen nanobubble water using gas chromatography. The results show that the optimal equilibrium condition for sample pretreatment is 50 ℃ for 15 min. It has been confirmed that the headspace gas chromatography method is suitable for analyzing a wide range of hydrogen nanobubble water systems (with number concentrations ranging from 10⁶ to 10⁸ mL⁻¹ and average particle sizes ranging from 100 to 300 nm) prepared by most nanobubble generation methods, by detecting both number concentration and particle size distribution of hydrogen nanobubbles in hydrogen nanobubble water. When the number concentrations of hydrogen nanobubbles are within the range of 6.7×10⁶-3.8×10⁸ mL⁻¹, the corresponding measured hydrogen contents fall between 0-3.12 mg/L. The changes in number concentrations of hydrogen nanobubbles are consistent with the corresponding hydrogen contents, and the detection process can be completed within 2 minutes. This method is simple and efficient, and can fulfill the test requirements regarding different number concentrations of hydrogen nanobubble water, providing a feasible option for quantifying the total hydrogen content in hydrogen nanobubble water. It facilitates further research on their significant applications of hydrogen nanobubbles in various fields and enables the evaluation of nanobubble generator performance.

Graphene oxide (GO) membranes were widely used for dyestuffs separation in complex wastewater due to their excellent physical and chemical properties and unique water channeling. The formation of nanobubbles-graphene oxide (NBs-GO) membranes by adsorption of nanobubbles (NBs) onto GO was expected to improve the dye separation performance of the membranes. The NBs-GO membranes were used to treat dyestuffs wastewater simulated by methylene blue solution. The water permeability, retention rate and stability of the membranes were determined, and the effects of factors such as dyestuff type and concentration, membrane thickness, and GO preparation conditions on the membrane performance were investigated. The results showed that the water permeability of the NBs-GO membrane was 50.8% higher than that of the traditional GO membrane, and the retention rate of methylene blue was maintained at 99.88%, which was superior to that of the traditional GO membrane. In addition, the NBs-GO membrane showed good stability within 72 h, and the retention rate was always maintained above 90%. The NBs-GO membranes maintained excellent water permeation performance even when the dyestuffs type, concentration and membrane thickness were changed. Therefore, the introduction of nanobubbles provides a new idea to improve the dyestuffs separation efficiency of GO membranes, which shows great potential in the treatment of dyestuffs wastewater, and this discovery is expected to open up a new path for the advancement of dye wastewater treatment technology.

Ozone micro-nano bubbles are known for their beneficial traits, such as high ozone utilization and mass transfer rates. In this study, ozone micro-nano bubbles were utilized to degrade the ultraviolet filter, diethylamino hydroxybenzoyl hexyl benzoate (DHHB). The characteristics of ozone micro-nano bubbles and their degradation mechanism on DHHB were studied by varying dissolved gas modes and liquid-phase ozone concentrations, and the impacts of temperature, pH, natural organic matter and different ion strengths on the degradation efficiency were explored. The results indicated that the oxidation efficiency of ozone micro-nano bubbles exceeded that of conventional ozone bubbles. The concentration of liquid-phase ozone, hydroxyl radicals, hydroxyl radical yield, and ozone utilization rate in the system increased significantly. The DHHB removal rate achieved 87.3% within 60 min at 25 °C, with a gas-phase ozone concentration of 10.22 mg/L and pH of 11. The removal effectiveness was 2.02 times greater than that of traditional ozone bubbles. Natural organic matter and bicarbonate ions inhibited the degradation of DHHB to different extents. According to the quenching test, 65.2% of DHHB degradation was contributed by hydroxyl radicals and 14.9% by superoxide radicals. This study confirms the feasibility of utilizing an ozone micro-nano bubble system for treating DHHB in water, and offers a theoretical basis for the practical implementation of this system.

In the Zero Liquid Discharge (ZLD) process of coking wastewater, mechanical vapor recompression (MVR) evaporation crystallization is employed to treat membrane-concentrated liquor, ultimately yielding highly saline concentrated wastewater, which is challenging to treat using conventional oxidation methods. Ozone micro nano bubble technology can enhance ozone mass transfer efficiency and augment its oxidation capability, making it a promising method for treating MVR-concentrated discharge. To verify the feasibility of engineering applications of this technology, this study focused on MVR-concentrated discharge and compared the ozone mass transfer rate and organic degradation efficiency between ozone micro nano bubbles and conventional macrobubbles. It analyzed the impact of salinity and organic concentration on the treatment efficiency of both ozone oxidation processes from technical and economic perspectives, thereby delineating the applicable scope of ozone micro nano bubble technology for high-salinity wastewater treatment. The results indicated that as the salinity increased from 0.1 mol/L to 1 mol/L, the ozone mass transfer coefficients for ozone micro nano bubbles and conventional macrobubbles increased by 0.13 and 0.09 times, respectively, with the ozone self-decomposition rate rising by 2.10 and 1.38 times, respectively. When treating high-salinity and high-organic wastewater (TOC 57.2-587.6 mg/L, conductivity 3.47-28.6 mS/cm), ozone micro nano bubble technology could enhance TOC removal rates by 0.50 to 3.76 times compared to conventional macrobubble technology, while reducing energy consumption per ton of water by up to 71%. When treating ultra-high salinity and ultra-high organic wastewater (TOC 5 626 mg/L, conductivity 164.3 mS/cm), the removal efficiency of micro nano bubbles tended to align with that of conventional macrobubbles, albeit with higher energy consumption per ton of water. The salinity and organic concentration of high-salinity wastewater significantly affect the treatment efficiency of ozone micro nano bubbles, and the appropriate ozone aeration method should be selected based on the wastewater characteristics in engineering applications

To improve the organic matter removal efficiency of important process stages such as raw water coagulation and pre/post ozone treatment in water plants, a comparative study was conducted on the ozone mass transfer efficiency under two aeration modes, i.e., micro-nano bubble (MNBs) aeration and ordinary aeration disc aeration. A small-scale experiment was conducted to investigate the impact of MNBs on the coagulation effect of raw water in water plants and study the removal efficiency of organic matter and algae in the pre and post-ozone treatment process stages under two aeration modes. The results showed that the number of nanobubbles produced by the microbubble generator in this study was 1.2×10⁶ mL⁻¹. Therefore, MNBs ozone (MNBs-O₃) had a longer residence time in water, and the utilization rate of MNBs-O₃ gradually increased within 20 minutes, while the ordinary aeration tray showed a trend of first increasing and then rapidly decreasing. When 12.5% of MNBs water was added to the raw water, the adsorption of hydrophobic organic compounds and the generation of hydroxyl radicals by MNBs could significantly improve the coagulation and precipitation effect of the raw water, and the decrease in UV₂₅₄ could reach more than 15%. The longer residence time also made it easier for MNBs-O₃ to convert large organic molecules into small molecules during the pre-ozone process. The molecular weight distribution results showed that 110 kDa peak disappeared and new peaks appeared in the parts less than 1 Da. The removal efficiency of BOD₅ was about 15% (much lower than 50% of ordinary aeration discs), and there was no significant change in TOC and UV₂₅₄. During the post-ozone process, BOD₅ of MNBs-O₃ group increased by 40%, and TOC increased by 36%, while UV₂₅₄ first increased and then decreased. The above results indicate that MNBs-O₃ can decompose aromatic organic compounds into oxygen-containing chain-like organic compounds during the pre-ozone process, and some large molecule organic compounds can be degraded into small molecules, which is helpful for the treatment of subsequent process stages. While during the post-ozone process, MNBs-O₃ can further improve the treatment efficiency of residual recalcitrant organic compounds in water. In addition, under the conditions of this study, the reduction rate of algae by MNBs-O₃ could reach 25% and MNBs-O₃ treatment did not increase the bromate concentration in water, and its efficiency could be further improved through the air flotation function of MNBs in the future. Although replacing ordinary aeration discs with MNBs increases electricity consumption by about 30%, MNBs significantly shorten the intake time and reduce O₃ usage. In summary, this study establishes a theoretical basis for the application of MNBs in raw water coagulation and pre/post-ozone treatment processes.

As the "blood" of drilling engineering in petroleum industry, drilling fluid plays a very important role in the process of oil and gas exploration and development. At the job site, drilling fluid is also an important source of drilling wastewater. With the further promotion of cleaner production and the improvement of environmental awareness, the requirements of drilling wastewater and its treatment on the job site have become more and more stringent. In response to the characteristics of good stability, high chemical oxygen demand and difficult degradation of drilling wastewater, micro-nano bubbles were used to improve gas utilization and mass transfer effect, and ozone gas was used to degrade high-difficulty and high-concentration organic matter. The aim was to solve the problems of high chromaticity and high COD of drilling wastewater. The indoor simulation experiment showed that after pretreatment, by using ozone micro-nano bubble technology, COD decreased from 47 328 mg/L to 131 mg/L, with the removal rate of 99.7%, and TOC decreased from 15 146 mg/L to 65.2 mg/L, with the removal rate of 99.6%. The removal rates of COD and TOC could reach more than 99.5%, and the ozone micro-nano bubble technology had a significant removal effect on high chromaticity and high COD. The experiment also showed that the flocculation precipitation and Fenton process combined with ozone micro-nano bubble technology could reduce the amount of ozone added, thereby reducing the investment and operating costs, making it an economical and efficient treatment method.

Aiming at the problem that traditional biodegradation can not degrade the chemical oxygen demand (COD) of benzene series, polyvinyl alcohol and other macromolecular organic compounds in resin wastewater, and can not meet the discharge standard, a microbubble O₃/H₂O₂ system was constructed to treat the secondary effluent of a resin factory deeply. The COD degradation effects of microbubble O₃ aeration and ordinary O₃ aeration were compared, and the effects of inlet O₃ concentration, H₂O₂ concentration and initial pH on COD degradation efficiency of microbubble O₃/H₂O₂ system were investigated. The mineralization effect of the system was verified by total organic carbon (TOC), and the active substances in microbubble O₃/H₂O₂ were detected by electron paramagnetic resonance spectrometer (EPR). Finally, the types of main organic substances in wastewater before and after degradation were analyzed by GC-MS, and the mechanism and path of COD degradation by microbubble O₃/H₂O₂ system were analyzed. The results showed that: (1) In the microbubble O₃/H₂O₂ system, the particle size of microbubbles was mainly distributed in the range of 10-50 μm, with an average particle size of 32.82 μm. Compared with ordinary aeration, microbubble O₃ system had a higher degradation rate of COD, which indicated that microbubbles could prolong the rising time of O₃ bubbles, increase the specific surface area of O₃ bubbles, and improve the mass transfer coefficient and utilization rate of O₃. (2) The analysis of influencing factors of COD degradation by microbubble O₃/H₂O₂ system showed that when O₃ concentration was 60 mg/L, H₂O₂ concentration was 29.37 mmol/L, and pH was 7 after 60 minutes of reaction, the COD degradation rate of secondary effluent of the resin factory by microbubble O₃/H₂O₂ system was 89.53%, and the treated effluent COD was 15.05 mg/L, meeting the requirements of Emission Standard of Pollutants for Synthetic Resin Industry (GB 31572-2015). (3) The EPR test showed that H₂O₂ could promote the microbubble O₃ system to produce more superoxide radicals ($\cdot{\mathrm{O}}_2^- $) and hydroxyl radicals (·OH), thus improving the oxidation capacity of the system and the degradation effect of COD. According to the results of GC-MS, the possible degradation path was inferred. Macromolecules in the secondary effluent from the resin factory, mainly composed of long-chain alkanes and cycloalkanes, underwent chain-breaking and ring-opening by O₃, and were mineralized or degraded into micromolecule substances, mainly small-molecule organic acids, under the action of ·OH and other free radicals

In order to scientifically grasp the spatial network structure of carbon emission efficiency in urban transportation and achieve sustainable development in the transportation industry, based on the data of nine national central cities in China from 2011 to 2020, a global super efficiency SBM model (GB-US-Super-SBM model) considering unexpected output was constructed to assess the transportation carbon emission efficiency; the revised spatial gravity model was used to construct the spatial correlation network and, based on this, the social network analysis method was applied to reveal the spatial network structure of transportation carbon emission efficiency and the influencing factors. The results showed that: (1) During the entire study duration, the overall transportation carbon emission efficiency of nine national central cities was relatively low, and there were considerable gaps among the cities. (2) The spatial correlation of transportation carbon emission efficiency in national central cities presented a network structure, gradually forming multiple network centers such as Tianjin, Xi'an and Zhengzhou; the spatial network of transportation carbon emission efficiency shows a trend of first strengthening and then weakening with 2017 as the node; cities such as Tianjin, Xi'an and Zhengzhou served as "bridges" and "intermediaries", playing a crucial role in the shaping of the spatial network. (3) Variations in economic development, urbanization, energy-saving technology and spatial proximity significantly influenced the spatial configuration of carbon emission efficiency in transportation. Among these factors, spatial proximity and differences in the level of economic development exerted the most substantial impact.

To study the influence of heavy-duty vehicle characteristic parameters on CO₂ emission, the effects of rolling resistance coefficient, wind resistance coefficient, tire dynamic radius, accessory maximum total power, mechanical efficiency and torque loss of main retarder and gearbox on CO₂ emissions were calculated by VECTO software, taking Chinese van, European C2 truck under different operating conditions and European intercity bus as examples. The sensitivity of different parameters to the variation of CO₂ emission was analyzed. The results showed that the variation range of parameters such as rolling resistance coefficient, wind resistance coefficient, total accessories power, and torque loss in each gear of main retarder and gearbox had a positive linear correlation with the variation range of vehicle CO₂ specific emission. The variation of 20% of each parameter would cause a maximum variation of 4.4%, 7.2%, 1.9%, 1.2% and 1.4% of CO₂ specific emissions, respectively. The influence of tire dynamic radius on CO₂ was nonlinear. The change range of CO₂ emission caused by negative tire dynamic radius variation was higher than that caused by positive tire dynamic radius variation; the −20% tire dynamic radius change range would cause about 7.1% change range of CO₂ specific emission. There was a negative linear correlation between the variation of mechanical efficiency of each gear of the main retarder and gearbox and the variation of CO₂ specific emission, and the variation of CO₂ emission caused by the mechanical efficiency deviation of −2.8% was about 2.3%. The research results can provide a reference for carrying out the design of the energy-saving and carbon-reducing improvement of heavy-duty vehicles.

The Yellow River Basin is regarded as an important "energy basin" in China. The spatial difference, sources of difference and dynamic evolution of carbon ecological security in resource-based cities were analyzed to optimize the overall layout of the basin's carbon ecological security. An evaluation index system for carbon ecological security of resource-based cities in the Yellow River Basin was constructed, and the TOPSIS model and Dagum Gini coefficient were selected to evaluate the level of carbon ecological security from 2012 to 2021 and analyze the sources of difference for carbon ecological security. The characteristics of spatial-temporal evolution were explored by the kernel density estimation method. The results showed that the carbon ecological security level had been increasing in the resource-based cities of the Yellow River Basin year by year, which had the characteristic of "slight increase - rapid increase", and the carbon ecological security level in the resource-based cities of the upstream region was higher than that in the middle and downstream regions. The spatial imbalance of carbon ecological security in the resource-based cities of different regions was very significant; the regional difference was the main source of the overall difference in carbon ecological security, and the impact of super variable density on the overall difference was increasing. According to the estimation results of the kernel density, the difference in carbon security levels was gradually narrowing among the resource-based cities in different regions of the Yellow River Basin, but the difference in the middle reaches was not obvious. Based on the "carbon peaking and carbon neutrality goals", the resource-based cities in different regions of the Yellow River Basin should formulate different regional carbon ecological security goals and measures to achieve a balance of carbon ecological security across the entire region.

Exploring the spatiotemporal patterns and influencing factors of land use carbon emissions in Chongqing can provide a scientific reference for further optimizing land use structure and implementing differentiated carbon and pollution reduction policies. Based on three periods of land cover data from 2000 to 2020, the regional differences and spatiotemporal dynamic characteristics of carbon emissions in Chongqing were revealed. The impact of socio-economic factors on spatial heterogeneity of carbon emissions was explored by integrating the STIRPAT model and the geographically weighted regression (GWP) model. The results showed that the net carbon emissions of Chongqing increased by a total of 37.2314 million tons from 2000 to 2020. Its temporal changes could be divided into a sharp increase stage and a slow increase stage, and there was still an imbalance between land use carbon sinks and carbon sources. The overall distribution pattern of net carbon emissions in Chongqing was characterized by a pattern of "high in the center and low on both wings". The growth of net carbon emissions in the main urban areas was the most severe, while it showed a slight increase in all districts and counties of the southeast in Chongqing. There was a significant spatial difference in the growth of net carbon emissions in the northeast. The factors influencing land use carbon emissions presented a strong spatial heterogeneity. The carbon emission intensity and per capita GDP were the key leading factors, followed by urban population size, general budget expenditure of local finance, and industrial structure. The intensity of carbon emissions had a more significant impact in the northeast of Chongqing, and the size of the urban population had a greater positive effect in the main metropolitan areas.

The rapid urbanization has generated a large amount of municipal solid waste (MSW) in China. In order to address the universal issue of garbage siege, China continues to improve the MSW management system. It has undergone different stages of development, such as landfill-based harmlessness, incineration-based harmlessness and reduction, comprehensive promotion of compulsory classification of garbage in major cities, and the comprehensive treatment and disposal of classified garbage. Taking Xiamen City as an example, the carbon emissions and characteristics of different MSW management stages were studied and analyzed. The results showed that the total amount of carbon emissions in Xiamen from 2000 to 2009 (harmlessness stage) increased from 254 900 t to 763 800 t, with an average annual growth of 13.19%. From 2010 to 2016 (harmlessness and reduction stage), the carbon emission intensity per ton of waste decreased each year due to the improvement of landfill gas collection efficiency and the continuous promotion of waste incineration reduction. However, the total emissions still increased from 279 500 t to 493 000 t. Since 2017, the city has implemented the four classifications of garbage, carried out the classification of kitchen waste, and built a pilot project for low-value recyclables. The carbon emission intensity has decreased from 324.74 kg/t to 178.11 kg/t, and the carbon emissions per ton of food waste, recyclables, kitchen waste and low-value recyclables were reduced by 5.69, 302.58-328.75, 83.19, and 884.66 kg, respectively. In the future, with the promotion of low-value recyclables classification and the construction of renewable resource centers, the carbon emission intensity and total amount of domestic waste will be further reduced, promoting the city's green and low-carbon development.

The activity level of mobile sources in Altay City was obtained by top-down investigation, the emission factor method was used to establish the mobile source emission inventory, and the temporal and spatial characteristics of mobile source emissions and inventory uncertainty analysis were carried out. The results showed that the total emissions of pollutants from mobile sources in Altay City in 2021 were CO 669.12 t, NO_x 617.92 t, SO₂ 29.85 t, NH₃ 32.61 t, VOCs 136.35 t, PM_2.5 35.74 t, PM₁₀ 38.06 t, BC 20.33 t, OC 6.41 t, respectively. Among them, CO, SO₂, NH₃ and VOCs mainly came from passenger vehicles, contributing more than 40%; NO_x mainly from agricultural machinery and trucks, contributing more than 30%; PM_2.5, PM₁₀, BC, OC mainly from agricultural machinery, contributing more than 75%. The spatial-temporal distribution characteristics showed that the emission was the highest from June to August, and the emission in densely populated urban areas was relatively higher than that in other regions. The uncertainty of the emission inventory of 9 pollutants from mobile sources was −39.23%-56.27%, and the calculation results of this inventory were relatively reliable.

It is of great importance for environmental governance to explore the influence of the emission of motor vehicle pollutants on the surrounding environment in urban roads. Scholars have established various emission models by analyzing the influencing factors of pollutants. According to their different research scales, the widely used models were divided, and the principles, applications and shortcomings of the models were summarized. At last, the COPERT model was selected to calculate the main air pollutant emissions in Xuefu Road, Lanzhou City, and the ANSYS software was used to simulate the impact of road traffic emissions on the surrounding environment. The results showed that the four main air pollutants NO₂, CO, PM_2.5 and PM₁₀ emitted on Xuefu Road during the working days were 67.7, 269.1, 15.1 and 22.8 t, respectively, and the light trunks, which accounted for 10.0% of the total number of motor vehicles, contributed a large amount, accounting for 50.5% and 69.1% of the total amount of motor vehicle NO₂ and PM emissions, respectively. By comparing the simulated values with the measured ones, it is found that the COPERT model has a good support for mesoscale research.

Based on the total pollutant emission accounting model of industrial parks and taking the total VOCs emission accounting of a key petrochemical industry park on the southeast coast of China as an example, a comparative study of inversion performances was compared on three optimization algorithms, including Nelder-Mead simplex method (NM), dual annealing optimization algorithm (DA) and particle swarm optimization algorithm (PSO), under different random error intensity and number of failure sites. Besides, the inversion performance of three optimization objective functions constructed by deviation sum of squares (Objective Function 1), logarithm transformation (Objective Function 2) and hyperbolic cosine transformation (Objective Function 3) was compared. The results showed that the inversion performance of PSO was related to the number of particles, but the overall performance implied that it was not suitable for the inversion optimization under the current conditions. NM and DA had better inversion accuracy (MARE<30%), but the inversion computation efficiency of NM was about 11-20 times higher than that of DA, and NM had the best inversion performance. All the three optimization objective functions were suitable for inversion optimization under current conditions (MARE<30%). Objective Function 1 and Function 3 performed better when the random error intensity was small and the number of failure sites was small, while Objective Function 2 performed better when the random error intensity was relatively large and the number of failure sites was relatively large.

MnO₂ nanorod and sea urchin microspheres were prepared using the hydrothermal method, and Mn-Ag composite oxides were prepared by in-situ doping with 5% Ag. The as-prepared samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), BET, Raman and other characterization techniques, and the removal performance of different catalysts for toluene was investigated. It was found that the amount of (NH₄)₂S₂O₈ would affect MnO₂ morphology. MnO₂ nanorods were formed when (NH₄)₂S₂O₈ was 2.28 g, while MnO₂ sea urchin microspheres were formed when (NH₄)₂S₂O₈ was 6.84 g. There was no morphology change of MnO₂ nanorods after 5% Ag doping. However, the nanowires on the surface of MnO₂ sea urchin microspheres increased when 5% Ag was doped, and the entanglement phenomenon occurred, forming a hollow bird's nest structure. After 5% Ag doping, there was no effect on the crystal of MnO₂ nanorods and sea urchin microspheres, both of which were α-MnO₂, but a diffraction peak of Mn₂O₃ appeared in 5% Ag-MnO₂ nanorods. Compared to MnO₂ nanorods, MnO₂ sea urchin microspheres showed an increasing trend of specific surface area, pore size and pore volume. The doping of Ag further increased the specific surface area, pore size and pore volume of MnO₂ sea urchin microspheres. For the toluene removal, MnO₂ sea urchin microspheres showed a better toluene removal performance than MnO₂ nanorods, and 5% Ag-MnO₂ sea urchin microspheres showed the best toluene removal performance among all the catalysts.

The three major lakes in Inner Mongolia Autonomous Region, Dali Lake, Ulan Suhai Lake and Hulun Lake, are significantly affected by geographical location and climatic environment. In particular, Dali Lake, as a tail lake, has evolved from a freshwater lake to a medium-salt lake. In 2022, Dali Lake, Ulan Suhai Lake and Hulun Lake were investigated, sampled and compared with the collected historical data. Piper three-line diagram, Gibbs diagram, spatial difference analysis, endmember diagram, ion ratio, and correlation analysis were used to study the hydrochemical characteristics and formation mechanism of the three lakes. The primary ion concentrations of the three lakes over the years were used to analyze the changes of the primary ion concentrations of the lakes in the past 10 years, and the reasons for the salinization of Dali Lake were analyzed from the perspective of environment. The results showed that: (1) The hydrochemical types of Dali Lake, Ulan Suhai Lake and Hulun Lake were ${\mathrm{HCO}}_3^- $-Na⁺-Cl⁻ type, ${\mathrm{HCO}}_3^- $-Cl⁻-Na⁺ type and ${\mathrm{HCO}}_3^- $-Na⁺-Cl⁻ type, respectively. (2) The spatial distribution characteristics of ions with large coefficient of variation in each lake were studied. The spatial distribution characteristics of ions (${\mathrm{HCO}}_3^- $ and total dissolved solid (TDS) ) in Dali Lake were high in the west and low in the east. The ions (${\mathrm{HCO}}_3^- $ and ${\mathrm{SO}}_4^{2-} $) in Ulan Suhai Lake generally showed a decreasing trend from the periphery to the middle. The spatial distribution of ions (${\mathrm{HCO}}_3^- $ and ${\mathrm{SO}}_4^{2-} $) of Hulun Lake was affected by the ion concentration in its inflow rivers. (3) The hydrochemical characteristics of the three lakes were mainly affected by evaporation and rock weathering. Among them, Dali Lake was affected by the combination of evaporite minerals and silicate minerals, Ulan Suhai Lake and Hulun Lake were mainly affected by silicate minerals, and the groundwater of Dali Lake had cation adsorption. (4) In the past 10 years, the ion concentrations of Dali Lake had been increasing year by year. The evaporation of the lake surface of Dali Lake was much larger than the precipitation of the lake surface, and the river recharge was decreasing year by year, which led to the shrinkage of the lake surface and the gradual increase of the salinization of the lake water. Fundamentally speaking, environmental factors reduced the amount of water entering the lake and increased the evaporation, ultimately accelerating the salinization of the lake.

Dissolved oxygen(DO) is an important indicator to reflect the quality of surface water, and it is one of key parameters for carrying out accurate comprehensive management of watersheds. Automatic monitoring data of surface water from 200 water quality automatic monitoring stations in Hubei Province from 2021 to 2022 were collected to study the spatial-temporal variation characteristics of DO and perform cluster grouping. The driving factors of DO variations of sixteen watershed areas were analyzed quantitatively by correlation coefficient method and multiple linear regression, and some suggestions for watershed management were proposed. The results indicated that:(1) DO concentration of surface water in Hubei Province showed significant seasonal difference as winter>spring>autumn>summer. Moreover, there was a significant diurnal variation from May to October. (2) Sixteen watershed areas in Hubei Province were divided into low oxygen zone, medium oxygen zone and rich oxygen zone. The low oxygen zone was mainly concentrated on Sihu area and the lower reaches of Hanjiang River area, with low DO concentration and saturation and high frequency of low DO occurrence in summer. The rich oxygen zone was mainly concentrated in Qingjiang area and the upper reaches of Danku Reservoir area of the Hanjiang River, with supersaturation in summer. The other watershed areas were medium oxygen zone, with stable saturation at a high level. (3) In terms of influencing factors, the low oxygen zone was characterized by compound pollution, the rich oxygen zone was affected by aquatic plant activities, and the medium oxygen zone was affected by temperature. Based on the characteristics of DO changes in different watershed areas, from the perspective of overall coordination of "three water" (water environment, water resource, water ecology), systematic watershed management methods should be set in a graded and partitioned manner, namely strengthening pollution source and process control in the low oxygen zone, preventing and controlling the risk of water blooms in the rich oxygen zone, and strictly controlling the total discharge in the medium oxygen zone.

Comprehensive and objective evaluation of the pollution status of urban river water quality is of great significance to the precise prevention and control of urban river water pollution. Based on the data of 7 water quality indicators of pH, dissolved oxygen (DO), permanganate index (COD_Mn), chemical oxygen demand (COD_Cr), total phosphorus (TP), ammonia nitrogen (NH₃-N) and fluoride (F⁻) of 13 important rivers in Cangzhou City in 2022, the principal component analysis (PCA) method was employed to extract the leading indicators causing changes in river water quality and to diagnose the pollution status of the rivers. Subsequently, the weights of water quality indicators were used to calculate the comprehensive scores for each river monitoring section and different seasons and analyze the spatial and temporal distribution characteristics of river water quality. The results showed that : (1) The overall water quality of the 13 rivers in Cangzhou City was relatively good in 2022, with most water bodies meeting the Class Ⅲ water standards of Environmental Quality Standards for Surface Water (GB 3838-2002), while a few rivers reached the Class Ⅳ water standards in terms of COD_Mn and COD_Cr indicators. (2) The application of the PCA method allowed the transformation of the 7 water quality indicators into 2 principal components, with a cumulative variance contribution rate of 78.492%. Among them, the water quality indicators, COD_Mn, COD_Cr, TP, and F⁻, were significantly correlated with the first principal component and dominated the water quality changes in the study area. Moreover, these four indicators showed a significant positive correlation between each other. (3) The spatial analysis revealed that Canglang Channel was the most polluted among the 13 monitored rivers, and the river pollution in the northeast of Cangzhou City was worse than that in the northwestern and southern areas. (4) The seasonal analysis indicated that the seasonal variation for water pollution in urban rivers was in the following order: summer>spring>winter>autumn. The analysis results could provide reference for the control strategy of urban river water pollution in Cangzhou City.

Drug-resistant bacteria and antibiotic resistance genes (ARGs) exist widely in the environment due to the extensive application of antibiotics, which affect the therapeutic effect of antibiotics on diseases and pose a great threat to human health and ecological security. Studies have shown that constructed wetlands (CWs) can effectively remove ARGs, but the effect of composite CWs on ARGs removal in northern China in winter is still unclear. Tianjin Lingang CWs, a compound of regulating pond, horizontal subsurface flow wetland and surface flow wetland, was used as the research object to study the removal effect of ARGs in winter. Water samples were collected from different functional zones, and 16S rRNA genes, ARGs, mobile genetic elements (MGEs) and bacterial population composition in water were detected by high-throughput quantitative PCR. The removal effect of ARGs was comprehensively analyzed, and the key factors affecting the removal effect during winter operations were discussed. The results showed that the absolute abundance of 16S rRNA gene was 2.70×10⁴-1.41×10⁵ copies/mL. The total detection rate of ARGs was 72.5%, in which floR and sul2 did not originate from influent water. The abundance of ARGs in different functional zones was significantly different, and the removal effect of ARGs in different functional zones was also significantly different. Overall, CWs in Tianjin Lingang had the best removal effect on aminoglycoside resistance genes and multi-drug resistance genes, with total absolute abundance removal rates of 85.59% and 47.78%, and total relative abundance removal rates of 97.09% and 89.44%, respectively. The removal efficiency of β-lactam resistance genes was the worst, and the total absolute abundance and relative abundance removal rates were −404.40% and −2.01%, respectively. The removal rates of total absolute abundance of ARGs were 38.05%, −7.78% and −2.41% in regulating pond, horizontal subsurface flow wetland and surface flow wetland, and the total relative abundance removal rates were 75.02%, −45.60% and −7.75%, respectively. The removal effects of different functional zones were as follows: the regulating pond > surface flow wetland > horizontal subsurface flow wetland, in which the regulating pond had a better removal effect for the absolute abundance of other ARGs except tetracycline resistance genes, the horizontal subsurface flow wetland had a better removal effect for sulfonamides resistance genes, and the surface flow wetland had a certain removal effect for macrolide resistance genes. Low temperature, MGEs, functional zones of different process types and operation time were the key factors affecting the removal effect of ARGs. The non-selectivity of ARGs to bacterial hosts promoted the rapid spread of ARGS among various bacterial groups in Tianjin Lingang CWs system. It is suggested to strengthen the optimization technology research to improve the removal effect of new pollutant ARGs by CWs.

In order to study the spatial distribution, source and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in surface water of Guoyang mining area, gas chromatography-mass spectrometry (GC-MS) was used to detect and analyze the concentration of 16 kinds of priority control PAHs in surface water of the study area. The results showed that the concentration range of ∑PAHs in the surface water of Guoyang mining area was 93.59-1 701.77 ng/L, with an average content of 674.16 ng/L. The concentration range of monomer PAHs was nd-362.44 ng/L. Among monomer PAHs, the proportion of 2-ring, 3-ring and 4-ring PAHs was relatively high, while that of 6-ring PAHs was relatively low. Compared with the surface water in other regions of China, the concentration of PAHs in the surface water of the research area was at a moderate to high level. In terms of spatial distribution, there was a significant difference in the concentration of PAHs in the surface water of the study area. The closer to the mining area, the higher the concentration of PAHs. The molecular diagnostic ratio (MDR), positive matrix factorization (PMF) and principal component analysis (PCA) methods obtained similar source apportionment results. The results showed that PAHs in surface water mainly came from transportation sources, coal combustion sources and petroleum sources. The contribution rates of each pollution source obtained from PCA were 37.32% for coal combustion sources, 35.51% for transportation sources and 13.92% for petroleum sources, respectively. The contribution rates of each pollution source obtained from PMF model were 42.66% for transportation sources, 30.85% for coal combustion sources, and 26.49% for petroleum sources, respectively. The ecological risk assessment results indicate that BaA, BbF and BkF are at a high risk level, while the remaining monomer PAHs are at a moderate risk level. Among the 22 sampling points, only 6 are at the medium ecological risk level, and the rest are at the high ecological risk level. In general, the overall ecological risk of surface water in Guoyang mining area is at the medium to high risk level, which is potentially harmful to organisms, and ecological risk prevention needs to be strengthened.

Per- and polyfluoroalkyl substances (PFAS) are new pollutants under key control in China, and wastewater treatment plants are important nodes for their entry into water bodies. Most of the current wastewater treatment plant processes are integrated after upgrading, and the removal effects of PFAS by each process are different. In order to explore the removal effect of the current typical upgraded wastewater treatment processes on PFAS, the characteristics and concentration of PFAS components in each operating unit of the improved A²O and improved OD processes in a sewage treatment plant in Beijing were analyzed, the contribution of different units to the removal of PFAS components was studied, and the effect and mechanism of the removal of PFAS by the two processes were discussed. The results showed that: (1) The short-chain substitution effect had emerged within the scope of the treatment plant, and the main PFAS in the influent of the two typical wastewater treatment processes were perfluoropentanoic acid (PFPeA), perfluorobutanoic acid (PFBA) and perfluorobutane sulfonate (PFBS). (2) The decomposition of PFAS precursors caused by biochemical treatment units and ultraviolet disinfection tanks, and the interception, filtration, adsorption and precipitation of PFAS by grates, MBR tanks and sedimentation tanks were important mechanisms for the change of PFAS occurrence characteristics in the two typical wastewater treatment processes. (3) The overall removal efficiency of total PFAS concentration by improved A²O and OD processes was 60.65% and 82.62%, respectively. The former had a prominent removal effect on PFPeA and PFBS, while the latter had a good removal effect on all short-chain PFAS except perfluorohexanoic acid (PFHxA). The upgrading of the wastewater treatment processes has improved the removal effect of some PFAS to a certain extent, and especially the improved OD process has a better removal effect on PFAS.

Twenty-two sludge samples were collected from 13 cities in the Yangtze River Delta region, and were used to investigate the concentration, size, speciation distribution, and bioavailability of silver (Ag) in sewage sludge. Meanwhile, the leaching toxicity and human health risks of Ag in sewage sludge were evaluated by the leaching toxicity procedure for solid waste and the health risk evaluation method recommended by the US Environmental Protection Agency. The results showed that the Ag concentration in varied sludge was significantly different (0.08-721 mg/kg), and the average Ag concentration in different types of sludge exhibited an order of industrial sludge (101 mg/kg) > mixed sludge (1.89 mg/kg) > municipal sludge (0.99 mg/kg). The results of single particle inductively coupled plasma mass spectrometry (spICP-MS) indicated that Ag-containing nanoparticles existed in different types of sludge and the size fell in the range of 17.7-19.0 nm. The analysis results of the occurrence forms indicated that the proportions of weakly acidic extracted Ag were higher in two types of industrial sludge with acidic or low organic matter content (S17 and S22, Nanjing), which were 60.0% and 15.6%, respectively. However, Ag in the remaining 20 types of sludge was mainly found in stable fractions (residual fraction and iron manganese oxidation fraction), indicating that the migration ability of Ag in most of the sludge (90.9%) in this region was relatively low. The EDTA extraction efficiency results indicated that, except for one acidic industrial sludge (S17, Nanjing), the bioavailability of Ag in the other 21 types of sludge was relatively low. The results of leaching toxicity indicated that except for one industrial sludge with low organic matter content (S22, Nanjing), whose Ag had a high leaching toxicity risk, the leaching toxicity risk of Ag in other sludge was relatively low. The results of the human health risk assessment indicated that Ag in the sludge from the Yangtze River Delta region did not pose a significant non-carcinogenic risk to adults and children. The above results suggest that from the perspective of Ag, the environmental risks of municipal and mixed sludge in the Yangtze River Delta region are relatively low, except for some industrial sludge.

During the municipal sludge drying process, the detection of internal moisture poses challenges. To accurately predict the variation pattern of internal moisture during the hot air drying process of municipal sludge, Back Propagation (BP) neural network and GA-BP (Genetic Algorithm Back Propagation) neural network algorithms were utilized to establish moisture prediction models for the municipal sludge hot air drying process, with drying time, drying temperature, sludge layer thickness, and flow differential pressure as input variables, and moisture content as the output variable. Moreover, a sensitivity analysis was conducted on the GA-BP neural network to investigate the impact of the four input variables on the prediction outcomes. The results indicated that the coefficients of determination (R²) for the BP and GA-BP moisture prediction models on the test set were 0.999 55 and 0.999 64, with root mean square errors (RMSE) of 0.513 17 and 0.455 23, respectively, demonstrating that the GA-BP algorithm-based prediction model achieved better performance, accurately predicting the dynamic changes of moisture during the municipal sludge drying process. The sensitivity analysis revealed that drying time had the most significant impact on the GA-BP moisture prediction model. These findings could provide a theoretical basis for optimising sludge drying processes and procedures and offer a reference for the resource utilization of sludge.

Bentonite is widely used for the construction of anti-seepage barriers in hazardous waste landfills due to its excellent anti-seepage performance, but its impermeability is usually affected by leachate and stress. Different concentrations of cationic solutions were set up by leachate sampling and analysis to investigate the influence law of actual leachate components on the anti-seepage performance of bentonite. Ca²⁺ was chosen as the characteristic cation, and the variation rule of the bentonite permeability coefficient under different stress conditions was studied. Meanwhile, the influence law of chemical compatibility of bentonite was elucidated under the action of leachate composition and stress combined with Zeta potential and DLVO theoretical calculation. The results show that the concentration of Al³⁺, Fe³⁺, Zn²⁺, Ni²⁺, Cu²⁺, Fe²⁺, Mn²⁺ in the leachate is in the range of 0-0.20 mmol/L, which has less influence on the expansion and permeability characteristics of bentonite. The concentration of Mg²⁺, Ca²⁺, K⁺, Na⁺ is in the range of 0.20-50 mmol/L, and Ca²⁺ has more influence on the expansion capacity and permeability characteristics of bentonite. When the concentration increases from 1 mmol/L to 50 mmol/L, the permeability coefficient rapidly increases from 1.15×10⁻⁷ cm/s to 6.34×10⁻⁶ cm/s. Ca²⁺ concentration and stress usually affect the permeability characteristics of hydrated bentonite by affecting its porosity, and the permeability coefficient gradually decreases with increasing pressure under the same Ca²⁺ concentration conditions. Zeta potential and DLVO theoretical analysis indicate that the increase in Ca²⁺ concentration leads to a decrease in the negative potential on the surface of bentonite and thickness of the double layer of bentonite, which decreases the interlayer spacing of montmorillonite in bentonite, and then depress the swelling and permeability characteristics of bentonite. Therefore, the solidification and stabilization process of hazardous waste during the landfill process should be optimized, to reduce Ca²⁺ content in the leachate at the source. Meanwhile, new bentonite composite materials should be developed to improve the impermeability of bentonite in Ca²⁺ as well as other salt solutions to prevent and control the risk of leakage of hazardous waste landfills.

Clarifying the spatial distribution of ecosystem services and service clusters in the mountain-river-sea coupling key zones is of great significance for regional ecological function management and ecosystem service capacity improvement. To assess the level of ecosystem services and the capacity of multiple ecosystem services in the southwestern Guangxi Karst-Beibu Gulf in 2018 through the InVEST model and multiple ecosystem services landscape index, and then to explore ecosystem service trade-offs/synergistic relationships and distribution patterns, and to identify the different service clusters through the self organizing feature map. The results showed that the multiple ecosystem service capacity of the mountain-river-sea coupling key zone was high, with the MESLI average of 1.65. The water yield and food production showed a distribution characteristic of decreasing from southeast to northwest, and MESLI and carbon storage and sequestration, soil conservation, habitat quality, and water quality purification services showed the distribution characteristics of low in the middle and high in the surrounding areas. As the topographic gradient increases, water yield and food production gradually decrease, and MESLI, carbon storage and sequestration, soil conservation, habitat qulaity, and water quality purification increased with the increase of topographic potential gradient. The ecosystem services were mainly synergistic with each other, and food production and carbon storage, habitat qulaity, soil conservation, and water quality purification were trade-offs, with the high trade-off areas mainly distributed in the key zone of Zuojiang River and Youjiang River basins and the key zone of Beibu Gulf coast. The mountain-river-sea coupling key zones can be divided into four categories, namely, ecological conservation, soil conservation, food supply, and human habitat bundles. Among them, the ecological conservation bundle has the largest distribution area and is mainly distributed in the mountainous areas of northwestern Karst key zone, and the areas of southeastern Shiwan Mountain and Liuwan Mountain, with the largest MESLI, while the habitat bundle is mainly distributed around the food supply bundle, with the smallest distribution area and the smallest MESLI. Therefore, the region needs to strengthen the ecological management and restoration of the habitat bundles, which is conducive to improving the multiple ecosystem service capacity of the mountain-river-sea coupling key zone, and promoting the coordinated and sustainable development of the region.

Adding quaternary ammonium compounds (QACs) as algal removal agents is an effective emergency response means for the problem of algal blooms caused by eutrophication,in freshwater lakes, and their dosage and environmental toxicity have received widespread attention. To clarify the effective concentration and safety of a new QAC algal removal agent, didecyl methylpropyl ammonium iodide (DMPAI), the toxic effects of it on planktonic algae, mainly Microcystis aeruginosa, Daphnia magna, and zebrafish embryos were determined at different concentrations. The results showed that DMPAI at the concentration of 0.5-2 mg/L could reduce 46.77% of the chlorophyll a in the water within 24 h, and reduce the number of Microcystis aeruginosa to 34% of its original level. At this concentration level, it did not affect the survival and reproduction of Daphnia magna, but retarded the growth of Daphnia magna, and the mortality rate of the zebrafish embryos was positively proportional to the concentration of DMPAI, with the maximum mortality rate of 19.00%. There were also the phenomena such as hatching in advance and heartbeat slowing, but it did not significantly affect the body length changes of juvenile fish.

In order to investigate the effects of flooding conditions and vegetation types on the microbial community structure and denitrification function genes of the ecotone zone of Lake Erhai, the microorganisms present in the soil and sediment of the ecotone zone of Lake Erhai were investigated under three flooding scenarios (no-flooding area, intermittent inundation area, constant inundation area) and with six different types of vegetation cover (grassland, woodland, forest-grassland, emergent vegetation, submerged vegetation, and no vegetation). The investigation was conducted using the 16S rRNA gene high-throughput sequencing and fluorescence quantitative PCR technologies to determine changes in microbial community structure and functional gene abundance and the impact of flooding and vegetation cover on soil and sediment microbial communities in the ecotone zone of Lake Erhai. The results showed that as the area with the most frequent material exchange and energy flow in the lakeshore, the interface zone was affected by water level fluctuations, so it became a complex environmental condition. The relative abundance of important microbial groups in nitrogen cycling in this soil/sediment, such as Chloroflexi and Nitrospirota, was higher than in the land and water zone. The vegetation cover mainly affected the microbial community composition and α Diversity in the sediment in the water land. The difference in the abundance of microbial denitrification functional genes revealed the spatial distribution characteristics of denitrification microorganisms in the ecotone zone. A higher abundance of functional genes in landward and interface zones indicated a stronger microbial denitrification activity. The abundance of functional genes during the removal of nitrogen from soil or sediment in the lakeshore of Lake Erhai was affected by several key factors, including water content, carbon-to-nitrogen ratio, organic carbon, and nitrite nitrogen. The difference in the concentration of these factors was the primary cause of the variation in the abundance of functional genes for nitrogen removal under various flooding conditions and vegetation cover.

It is of great significance to study the characteristics of vegetation communities and their influencing factors in different industrial sites in antimony mining areas for ecological restoration and vegetation reconstruction. The plant communities of various industrial sites of Wuyi antimony mine in Nandan County were taken as the research object, and the undamaged plant communities around the antimony mining area were selected as the control area, to explore the species composition and diversity of plant communities in different industrial sites (mining area, smelting area and tailings area) in the antimony mining area and their relationship with soil factors. The results showed that the community composition of each industrial site of antimony ore was dominated by Compositae and Poaceae, and the two families of plants were the community-building species and dominant species in the industrial site of the antimony mining area. There were significant differences in plant community composition between the control area and each industrial site (P<0.05), and the plant community composition in the smelting area was significantly different from that in the mining area and tailings area (P<0.05). The important values of dominant species, Margalef index and Shannon index of each industrial site were shown as control area > mining area> tailings area > smelting area (P<0.05), indicating that the smelting area had the lowest community complexity and the simplest community structure, and the ecological degradation situation was more serious. Plant diversity in the mining area was positively correlated with organic matter, soil moisture content, pH, total potassium and total nitrogen content, and negatively correlated with total phosphorus, and antimony and arsenic concentrations. Total antimony, total arsenic and soil moisture content were important limiting factors affecting the species diversity of various industrial sites in antimony mines. Heavy metal concentration had the strongest effect on plant community diversity in tailings area and mining area, and soil moisture content had the strongest effect on smelting area. The results show that the number of plant species in industrial sites is decreasing, the vegetation diversity index is decreasing, and industrial activities such as mining have caused great damage and interference to the ecological environment of mining areas. The type of mining site and key environmental variables should be considered in the vegetation restoration plan for mining areas.

Epidemiologic studies have confirmed that air pollutants exposure could result in various adverse health outcomes, but the specific biological mechanism is still unclear. Oxidative stress (OS) induced by air pollution exposure has been confirmed as a classical regulatory mechanism that affects our health. In recent years, it has been found that the combined effect of lipid peroxidation induced by OS and iron accumulation can induce programmed cell death, which has been termed "ferroptosis". Thus, ferroptosis could be an important regulatory mechanism of adverse health outcomes induced by air pollutants exposure. To explore the mechanisms by which air pollution triggers ferroptosis, we reviewed and summarized the targets and regulatory mechanisms of ferroptosis in regulating adverse health outcomes caused by air pollution, based on existing research results. The result showed that fine particulate matter (PM_2.5), ozone (O₃) and cigarette smoke (CS) could induce ferroptosis by affecting key genes in iron metabolism and lipid peroxidation pathways. In a word, air pollutants could cause OS and reduce the antioxidant capacity, then reduce the resistance of ferroptosis. This review further supplemented the mechanism of air pollution-induced diseases, which could provide theoretical support for potential disease treatment strategies.

The study focuses on Tai Shan Temple in Jiawan, Xinxiang City, investigating the concentrations of eight heavy metal elements (Hg, As, Cr, Ni, Cu, Zn, Cd, Pb) in surface dust and conducting health risk assessment and source apportionment of heavy metal pollution. Results reveal spatial variability in the concentrations of seven heavy metal elements (excluding As) in temple surface dust, exceeding the soil environmental background values of the southern Yu Plain. The exceedance rate of Cu concentrations over soil background values at each sampling point reaches 91.03%, with Ni showing an average exceedance rate of 151.1%. Potential carcinogenic and non-carcinogenic risks posed by heavy metals in surface dust to children and adults were found to be below standard values, with Cr and Pb identified as the primary non-carcinogenic factors. Children were found to face higher health risks from heavy metals in surface dust compared to adults, primarily through the hand-to-mouth ingestion pathway. The health risk index of heavy metals exhibited an initial increase followed by a decrease with increasing distance from the furnace core, with peak values generally observed at a gradient of 20 meters. Matrix factor analysis indicated that Hg and Pb in surface dust mainly originated from architectural paint pollution, while Cr, Cu, Ni, and Zn primarily originated from temple incense pollution, and Cd and As were predominantly sourced from agricultural and livestock activities. Temple incense pollution contributed significantly to the pollution sources, accounting for 40.96%, followed by agricultural and livestock pollution at 37.40%, and temple construction pollution at 21.64%.