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2026 Vol. 44, No. 2
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2026, 44(2): 1-14.
doi: 10.13205/j.hjgc.202602001
Abstract:
Membrane technology has become an important technology in the water treatment industry due to its advantages of high separation efficiency， stable performance and good effluent quality. However， membrane fouling—leading to membrane flux decline， shortened operational cycles， and increased treatment costs—remains a critical bottleneck hindering the further development of this technology. To accurately analyze pollutant composition， elucidate the spatial structural characteristics of fouling layers， dynamically monitor pollution evolution patterns， and clarify underlying mechanisms， the scientific selection and application of membrane fouling characterization methods are essential. This review focuses on membrane fouling issues in membrane-based wastewater treatment. Based on the spatiotemporal resolution of characterization techniques， fouling characterization methods are classified into three categories： ex-situ characterization， in-situ characterization， and real-time monitoring. The principles， technical advantages， and application limitations of each method are systematically reviewed and compared. By discussing applicable scenarios for each method， this work provides insights to deepen the mechanistic understanding of membrane fouling and advance the development of fouling control strategies.
Membrane technology has become an important technology in the water treatment industry due to its advantages of high separation efficiency， stable performance and good effluent quality. However， membrane fouling—leading to membrane flux decline， shortened operational cycles， and increased treatment costs—remains a critical bottleneck hindering the further development of this technology. To accurately analyze pollutant composition， elucidate the spatial structural characteristics of fouling layers， dynamically monitor pollution evolution patterns， and clarify underlying mechanisms， the scientific selection and application of membrane fouling characterization methods are essential. This review focuses on membrane fouling issues in membrane-based wastewater treatment. Based on the spatiotemporal resolution of characterization techniques， fouling characterization methods are classified into three categories： ex-situ characterization， in-situ characterization， and real-time monitoring. The principles， technical advantages， and application limitations of each method are systematically reviewed and compared. By discussing applicable scenarios for each method， this work provides insights to deepen the mechanistic understanding of membrane fouling and advance the development of fouling control strategies.
2026, 44(2): 15-24.
doi: 10.13205/j.hjgc.202602002
Abstract:
To investigate the current status， hotspots， and future development trends of quantitative research on microplastics and nanoplastics in the marine environment， this study， based on the Web of Science Core Collection， uses CiteSpace to conduct a visual analysis of 422 related literature in the field of microplastics and nanoplastics quantification in the marine environment from 2012 to 2023. The study unfolds from multiple aspects such as annual publication volume， research institutions， national and author collaboration networks， keyword clustering and emergence， and co-citation analysis. The results indicate that the volume of publications on the quantification of microplastics and nanoplastics in the marine environment is generally on the rise， currently in a phase of research innovation. In this field， China leads in the number of publications but needs to enhance collaboration with other countries； Italy demonstrates a promising developing trend with a high publication volume and excellent international cooperation. It is noteworthy that foreign institutions have closer collaborations， and most core authors and highly cited papers are from abroad. Keyword clustering analysis reveals that research mainly focuses on the occurrence characteristics， characterization， and quantification， and the ecological risks of microplastics and nanoplastics. Keyword burst analysis suggests that the standardization of sample collection and detection methods， the characterization and quantification of nanoscale plastics， and the numerical modeling and prediction of source-sink processes of micro/nanoplastics are expected to become key directions and hotspots in future research.
To investigate the current status， hotspots， and future development trends of quantitative research on microplastics and nanoplastics in the marine environment， this study， based on the Web of Science Core Collection， uses CiteSpace to conduct a visual analysis of 422 related literature in the field of microplastics and nanoplastics quantification in the marine environment from 2012 to 2023. The study unfolds from multiple aspects such as annual publication volume， research institutions， national and author collaboration networks， keyword clustering and emergence， and co-citation analysis. The results indicate that the volume of publications on the quantification of microplastics and nanoplastics in the marine environment is generally on the rise， currently in a phase of research innovation. In this field， China leads in the number of publications but needs to enhance collaboration with other countries； Italy demonstrates a promising developing trend with a high publication volume and excellent international cooperation. It is noteworthy that foreign institutions have closer collaborations， and most core authors and highly cited papers are from abroad. Keyword clustering analysis reveals that research mainly focuses on the occurrence characteristics， characterization， and quantification， and the ecological risks of microplastics and nanoplastics. Keyword burst analysis suggests that the standardization of sample collection and detection methods， the characterization and quantification of nanoscale plastics， and the numerical modeling and prediction of source-sink processes of micro/nanoplastics are expected to become key directions and hotspots in future research.
2026, 44(2): 25-32.
doi: 10.13205/j.hjgc.202602003
Abstract:
This study systematically reviewed the policies， regulations， and standards governing industrial wastewater reuse in China， and identified the institutional challenges in policy implementation. Through a case study of reclaimed water utilization at a semiconductor manufacturer in Jiangsu Province， the research explored feasible approaches for water reuse in the electronics industry via integrated policy and water quality analysis. Key findings include： 1） The existing regulatory framework remains incomplete， with regulatory conflicts between end-of-pipe pollution control requirements and reuse demands， and the lack of scenario-specific standards and specifications constitutes a major constraint on development； 2） The reclaimed water produced by the semiconductor manufacturer through the dual-membrane （ultrafiltration-reverse osmosis） treatment process is significantly superior to the limit values specified in the Chinese National Standards GB/T 19923—2024， GB/T 18921—2019， and GB/T 25499—2010， and outperforms the water quality of surrounding natural water bodies and can meet the process water demands of most enterprises in the industrial park. Given the established technical feasibility of water quality compliance， the core challenge for this semiconductor manufacturer's wastewater reuse lies in resolving the regulatory constraints on the application of reclaimed water for industrial and scenic environmental purposes.
This study systematically reviewed the policies， regulations， and standards governing industrial wastewater reuse in China， and identified the institutional challenges in policy implementation. Through a case study of reclaimed water utilization at a semiconductor manufacturer in Jiangsu Province， the research explored feasible approaches for water reuse in the electronics industry via integrated policy and water quality analysis. Key findings include： 1） The existing regulatory framework remains incomplete， with regulatory conflicts between end-of-pipe pollution control requirements and reuse demands， and the lack of scenario-specific standards and specifications constitutes a major constraint on development； 2） The reclaimed water produced by the semiconductor manufacturer through the dual-membrane （ultrafiltration-reverse osmosis） treatment process is significantly superior to the limit values specified in the Chinese National Standards GB/T 19923—2024， GB/T 18921—2019， and GB/T 25499—2010， and outperforms the water quality of surrounding natural water bodies and can meet the process water demands of most enterprises in the industrial park. Given the established technical feasibility of water quality compliance， the core challenge for this semiconductor manufacturer's wastewater reuse lies in resolving the regulatory constraints on the application of reclaimed water for industrial and scenic environmental purposes.
2026, 44(2): 33-39.
doi: 10.13205/j.hjgc.202602004
Abstract:
The COVID-19 pandemic highlighted critical shortcomings in traditional public health surveillance systems， particularly in terms of delayed response times and insufficient spatial coverage during the early stages of the outbreak. These limitations hindered the accurate tracking of viral spread and emphasized the urgent need for complementary surveillance approaches. In this context， Wastewater-based Epidemiology （WBE） has emerged as a promising strategy for cost-effective， large-scale monitoring of pathogen circulation， gaining global attention due to its potential for broad population coverage. However， the sensitivity and accuracy of WBE in detecting viral pathogens heavily depend on the efficiency of viral concentration and enrichment from wastewater samples， in which viruses typically exist at extremely low concentrations. Therefore， the development of effective viral concentration methods is essential to enhance the reliability， sensitivity， and overall accuracy of wastewater-based surveillance. In this study， a novel ultrafiltration-based viral enrichment method aimed at improving the efficiency of viral monitoring in wastewater was developed. The method was systematically evaluated for its applicability in detecting various viral pathogens in municipal wastewater. The results demonstrated that the ultrafiltration-based concentration method achieved high recovery rates （>40%） for the porcine epidemic diarrhea virus （PEDV）， transmissible gastroenteritis virus （TGEV）， and bacteriophage Phi6， with a lower detection limit of 10 copies/mL. These findings indicated the method’s capability to effectively concentrate and detect viral particles at trace levels， which is critical for early outbreak detection and ongoing monitoring. To further validate the feasibility and performance of the proposed method， a one-month field monitoring campaign was conducted in August 2023 at five sites in Haidian District， Beijing. Wastewater samples （n=50） were collected from the local sewage network， and SARS-CoV-2 concentrations were tracked over time using ultrafiltration combined with RT-qPCR quantification. Among the 50 collected samples， 49 （98.00%） tested positive for SARS-CoV-2， providing robust evidence of the virus’s persistent presence and circulation within the local wastewater system. Notably， the peak viral concentration observed in wastewater reached 1027.81 copies/mL. This study provides important technical support for improving the detection efficiency and sensitivity of wastewater viral monitoring， and has broad potential applications in various sectors， including environmental monitoring and water quality management.
The COVID-19 pandemic highlighted critical shortcomings in traditional public health surveillance systems， particularly in terms of delayed response times and insufficient spatial coverage during the early stages of the outbreak. These limitations hindered the accurate tracking of viral spread and emphasized the urgent need for complementary surveillance approaches. In this context， Wastewater-based Epidemiology （WBE） has emerged as a promising strategy for cost-effective， large-scale monitoring of pathogen circulation， gaining global attention due to its potential for broad population coverage. However， the sensitivity and accuracy of WBE in detecting viral pathogens heavily depend on the efficiency of viral concentration and enrichment from wastewater samples， in which viruses typically exist at extremely low concentrations. Therefore， the development of effective viral concentration methods is essential to enhance the reliability， sensitivity， and overall accuracy of wastewater-based surveillance. In this study， a novel ultrafiltration-based viral enrichment method aimed at improving the efficiency of viral monitoring in wastewater was developed. The method was systematically evaluated for its applicability in detecting various viral pathogens in municipal wastewater. The results demonstrated that the ultrafiltration-based concentration method achieved high recovery rates （>40%） for the porcine epidemic diarrhea virus （PEDV）， transmissible gastroenteritis virus （TGEV）， and bacteriophage Phi6， with a lower detection limit of 10 copies/mL. These findings indicated the method’s capability to effectively concentrate and detect viral particles at trace levels， which is critical for early outbreak detection and ongoing monitoring. To further validate the feasibility and performance of the proposed method， a one-month field monitoring campaign was conducted in August 2023 at five sites in Haidian District， Beijing. Wastewater samples （n=50） were collected from the local sewage network， and SARS-CoV-2 concentrations were tracked over time using ultrafiltration combined with RT-qPCR quantification. Among the 50 collected samples， 49 （98.00%） tested positive for SARS-CoV-2， providing robust evidence of the virus’s persistent presence and circulation within the local wastewater system. Notably， the peak viral concentration observed in wastewater reached 1027.81 copies/mL. This study provides important technical support for improving the detection efficiency and sensitivity of wastewater viral monitoring， and has broad potential applications in various sectors， including environmental monitoring and water quality management.
2026, 44(2): 40-49.
doi: 10.13205/j.hjgc.202602005
Abstract:
2-Chloro-4-nitrophenol （2C4NP） is a typical chloronitrophenol （CNPs）， characterized by persistence and high environmental toxicity. Currently， research on the degradation of 2C4NP by microbial electrolysis cells （MECs） is still limited， and the degradation mechanism remains unclear. In this study， a two-chamber MECs was constructed to systematically investigate the effects of external voltage， initial concentration of 2C4NP， and co-substrate types on the cathodic degradation of 2C4NP. Scanning electron microscopy （SEM） was used to analyze the microbial morphology， and high-performance liquid chromatography （HPLC）， ion chromatography （IC）， and LC/MS/MS were employed for qualitative and quantitative analysis of 2C4NP and its degradation intermediates， thereby elucidating the mechanism of 2C4NP degradation at the MECs cathode. Results showed that the application of an appropriate external voltage significantly promoted the degradation of 2C4NP. The initial concentration of 2C4NP had a significant impact on the degradation rate， and the degradation process followed different reaction kinetics under different co-substrate conditions. Under the optimal conditions （external voltage of 0.5 V， co-substrate of glucose， and initial concentration of 2C4NP at 30 mg/L）， the 72 h removal rate and dechlorination rate of 2C4NP reached 96.77% and 67.74%， respectively. SEM analysis revealed that microorganisms on the cathode surface aggregated， enhancing electron transfer efficiency among microorganisms and providing a basis for efficient degradation. HPLC， IC， and LC/MS/MS analyses indicated that the degradation of 2C4NP produced intermediate products such as 4-nitrophenol， paracetamol， and 2-chlorophenol. The partially removed chlorine and nitrogen were detected as Cl- and NO3-. These results suggest that the degradation of 2C4NP in the MEC cathode chamber mainly occurs through reductive dechlorination and denitration reactions.
2-Chloro-4-nitrophenol （2C4NP） is a typical chloronitrophenol （CNPs）， characterized by persistence and high environmental toxicity. Currently， research on the degradation of 2C4NP by microbial electrolysis cells （MECs） is still limited， and the degradation mechanism remains unclear. In this study， a two-chamber MECs was constructed to systematically investigate the effects of external voltage， initial concentration of 2C4NP， and co-substrate types on the cathodic degradation of 2C4NP. Scanning electron microscopy （SEM） was used to analyze the microbial morphology， and high-performance liquid chromatography （HPLC）， ion chromatography （IC）， and LC/MS/MS were employed for qualitative and quantitative analysis of 2C4NP and its degradation intermediates， thereby elucidating the mechanism of 2C4NP degradation at the MECs cathode. Results showed that the application of an appropriate external voltage significantly promoted the degradation of 2C4NP. The initial concentration of 2C4NP had a significant impact on the degradation rate， and the degradation process followed different reaction kinetics under different co-substrate conditions. Under the optimal conditions （external voltage of 0.5 V， co-substrate of glucose， and initial concentration of 2C4NP at 30 mg/L）， the 72 h removal rate and dechlorination rate of 2C4NP reached 96.77% and 67.74%， respectively. SEM analysis revealed that microorganisms on the cathode surface aggregated， enhancing electron transfer efficiency among microorganisms and providing a basis for efficient degradation. HPLC， IC， and LC/MS/MS analyses indicated that the degradation of 2C4NP produced intermediate products such as 4-nitrophenol， paracetamol， and 2-chlorophenol. The partially removed chlorine and nitrogen were detected as Cl- and NO3-. These results suggest that the degradation of 2C4NP in the MEC cathode chamber mainly occurs through reductive dechlorination and denitration reactions.
2026, 44(2): 50-56.
doi: 10.13205/j.hjgc.202602006
Abstract:
To improve the sand removal efficiency of thermally hydrolyzed sludge， this study proposed the use of a hydrocyclone for centrifugal desanding. In the experiments， a sand-containing xanthan gum solution with similar non-Newtonian fluid properties was used as a substitute for the sludge to evaluate the sand removal efficiency. The effects of xanthan gum concentration （0.2% to 0.4%）， sand particle size （50 to 214 μm）， and feed flow rate （4 to 6 m3/h） on sand removal efficiency and hydraulic loss were investigated. When the feed flow rate was fixed at 4 m3/h， increasing the xanthan gum concentration from 0.2% to 0.4% resulted in a decrease in the overall separation efficiency from 67.5% to 45.8%. Simultaneously， the underflow split ratio increased linearly from 72% to 76%. This indicated a negative correlation between solution concentration and sand removal efficiency， meaning that higher xanthan gum concentrations led to less efficient sand separation. For the 0.2% xanthan gum solution， the removal efficiency for particles smaller than 94 μm was below 50%， significantly lower than that for particles larger than 150 μm， which exceeded 65%. This demonstrated a positive correlation between particle size and removal efficiency， showing that larger particles are more easily separated. As the feed flow rate increased from 4 m3/h to 6 m3/h， the sand removal efficiency gradually improved. Specifically， the efficiency for sand particles in the size ranges of 50 to 94 μm， 94 to 150 μm， and 150 to 214 μm increased to 70%， 80%， and 95%， respectively. This indicated that increasing the feed flow rate enhanced the sand separation performance of the hydrocyclone， likely because higher flow rates result in stronger centrifugal forces， which in turn facilitate more effective separation. Moreover， hydraulic losses at both the inlet and outlet increased linearly with the flow rate. However， the pressure loss in the xanthan gum solution was consistently lower than that in the sand-water mixture. Furthermore， as the xanthan gum concentration increased， the pressure loss further decreased， suggesting that higher concentrations reduce hydraulic resistance. This study has clarified the primary factors affecting the sand removal efficiency of a hydrocyclone for non-Newtonian fluids， providing valuable theoretical guidance for the pre-treatment of thermally hydrolyzed sludge in industrial applications. Future research could explore the flow separation phenomena of different structures and real thermally hydrolyzed sludge within the hydrocyclone， potentially leading to an optimized design for the hydrocyclone's structure and operational parameters.
To improve the sand removal efficiency of thermally hydrolyzed sludge， this study proposed the use of a hydrocyclone for centrifugal desanding. In the experiments， a sand-containing xanthan gum solution with similar non-Newtonian fluid properties was used as a substitute for the sludge to evaluate the sand removal efficiency. The effects of xanthan gum concentration （0.2% to 0.4%）， sand particle size （50 to 214 μm）， and feed flow rate （4 to 6 m3/h） on sand removal efficiency and hydraulic loss were investigated. When the feed flow rate was fixed at 4 m3/h， increasing the xanthan gum concentration from 0.2% to 0.4% resulted in a decrease in the overall separation efficiency from 67.5% to 45.8%. Simultaneously， the underflow split ratio increased linearly from 72% to 76%. This indicated a negative correlation between solution concentration and sand removal efficiency， meaning that higher xanthan gum concentrations led to less efficient sand separation. For the 0.2% xanthan gum solution， the removal efficiency for particles smaller than 94 μm was below 50%， significantly lower than that for particles larger than 150 μm， which exceeded 65%. This demonstrated a positive correlation between particle size and removal efficiency， showing that larger particles are more easily separated. As the feed flow rate increased from 4 m3/h to 6 m3/h， the sand removal efficiency gradually improved. Specifically， the efficiency for sand particles in the size ranges of 50 to 94 μm， 94 to 150 μm， and 150 to 214 μm increased to 70%， 80%， and 95%， respectively. This indicated that increasing the feed flow rate enhanced the sand separation performance of the hydrocyclone， likely because higher flow rates result in stronger centrifugal forces， which in turn facilitate more effective separation. Moreover， hydraulic losses at both the inlet and outlet increased linearly with the flow rate. However， the pressure loss in the xanthan gum solution was consistently lower than that in the sand-water mixture. Furthermore， as the xanthan gum concentration increased， the pressure loss further decreased， suggesting that higher concentrations reduce hydraulic resistance. This study has clarified the primary factors affecting the sand removal efficiency of a hydrocyclone for non-Newtonian fluids， providing valuable theoretical guidance for the pre-treatment of thermally hydrolyzed sludge in industrial applications. Future research could explore the flow separation phenomena of different structures and real thermally hydrolyzed sludge within the hydrocyclone， potentially leading to an optimized design for the hydrocyclone's structure and operational parameters.
2026, 44(2): 57-66.
doi: 10.13205/j.hjgc.202602007
Abstract:
Eutrophication and algal blooms are global environmental concerns. While traditional copper-based algicides are effective and cost-efficient， they cause secondary copper ion pollution and degrade water quality due to the accumulation of dead algae. This study introduces an innovative method for simultaneous algae removal and water purification using a copper-based microfiltration membrane that enables rapid treatment and facilitates high-quality water reuse. Through the oxidation effect of copper ions released at the membrane-water interface， the copper-based microfiltration membrane achieved 100% algae removal without additional chemicals. It combined physical interception with catalytic degradation， effectively eliminating a wide range of pollutants. The system removed 98.87% of turbidity while reducing ultraviolet absorbance， microcystin-LR concentrations， and total organic carbon by 28.54%， 42.9%， and 36.8%， respectively. Compared to traditional polymeric microfiltration membranes， the copper-based membrane demonstrated markedly enhanced efficiency in removing organic contaminants， significantly improving treated water quality and reuse potential. Through rapid hydraulic backwashing， the copper-based membrane effectively recovered its initial flux and maintained a consistent water flux of 65525.65 L/（m2·h）. The copper ion concentration in the filtrate remained at approximately 1.22×10-5 mol/L， well within the safety limits for drinking water. This study provides valuable insights for sustainable water treatment and aquatic ecosystem protection.
Eutrophication and algal blooms are global environmental concerns. While traditional copper-based algicides are effective and cost-efficient， they cause secondary copper ion pollution and degrade water quality due to the accumulation of dead algae. This study introduces an innovative method for simultaneous algae removal and water purification using a copper-based microfiltration membrane that enables rapid treatment and facilitates high-quality water reuse. Through the oxidation effect of copper ions released at the membrane-water interface， the copper-based microfiltration membrane achieved 100% algae removal without additional chemicals. It combined physical interception with catalytic degradation， effectively eliminating a wide range of pollutants. The system removed 98.87% of turbidity while reducing ultraviolet absorbance， microcystin-LR concentrations， and total organic carbon by 28.54%， 42.9%， and 36.8%， respectively. Compared to traditional polymeric microfiltration membranes， the copper-based membrane demonstrated markedly enhanced efficiency in removing organic contaminants， significantly improving treated water quality and reuse potential. Through rapid hydraulic backwashing， the copper-based membrane effectively recovered its initial flux and maintained a consistent water flux of 65525.65 L/（m2·h）. The copper ion concentration in the filtrate remained at approximately 1.22×10-5 mol/L， well within the safety limits for drinking water. This study provides valuable insights for sustainable water treatment and aquatic ecosystem protection.
2026, 44(2): 67-77.
doi: 10.13205/j.hjgc.202602008
Abstract:
Trichloroethylene （TCE）， a typical halogenated organic pollutant in groundwater， poses a serious threat to groundwater ecosystem and human health. Micrometer-sized zero-valent iron （mZVI） has attracted considerable attention for its ability in removing TCE. To further enhance the reactivity of mZVI， sulfidation modification is often employed. While traditional chemical sulfidation can improve the reactivity of mZVI， it suffers from high chemical reagent consumption and environmental pollution. In contrast， biological sulfidation， which utilizes sulfide produced by microbial metabolism to modify mZVI， is more environmentally friendly and cost-effective. However， the mechanisms underlying the effects of mZVI particle size and sulfate concentration on the sulfidation efficiency and dechlorination performance of biologically sulfidated mZVI remain unclear. Therefore， this study investigated the effects of mZVI particle size and sulfate concentration on the efficiency of TCE removal by biologically sulfidated mZVI with different particle sizes， and explored the underlying mechanisms. The results showed that the mZVI particle size significantly affected the biological sulfidation efficiency and TCE removal rate. 7 μm ZVI exhibited the fastest removal rate （0.16 d-1） due to its larger specific surface area. However， it was prone to agglomeration and might inhibit microbial growth， leading to the lowest degree of biological sulfidation. In contrast， 40 μm ZVI showed the highest content of reductive sulfur （81.92%） after biological sulfidation， and its reactivity was significantly better than that of the chemically sulfidated group with the same particle size， indicating that biological sulfidation was more effective for larger-sized mZVI. Additionally， sulfate concentration had a significant impact on the dechlorination performance of mZVI. The increase in sulfate concentration created a favorable environment for the growth of sulfate-reducing bacteria， increased the content of reductive sulfur on the mZVI surface， and thus enhanced the dechlorination efficiency of S-mZVI. When the sulfate concentration reached 700 mg/L， S-mZVI could completely remove TCE within 24 days. The dechlorination product results showed that the sulfate concentration was positively correlated with the degree of dechlorination， and high sulfate concentrations promoted the complete removal of chlorine atoms from TCE molecules. The findings can provide theoretical guidance and technical support for the bio-sulfidated mZVI remediation of TCE-contaminated groundwater.
Trichloroethylene （TCE）， a typical halogenated organic pollutant in groundwater， poses a serious threat to groundwater ecosystem and human health. Micrometer-sized zero-valent iron （mZVI） has attracted considerable attention for its ability in removing TCE. To further enhance the reactivity of mZVI， sulfidation modification is often employed. While traditional chemical sulfidation can improve the reactivity of mZVI， it suffers from high chemical reagent consumption and environmental pollution. In contrast， biological sulfidation， which utilizes sulfide produced by microbial metabolism to modify mZVI， is more environmentally friendly and cost-effective. However， the mechanisms underlying the effects of mZVI particle size and sulfate concentration on the sulfidation efficiency and dechlorination performance of biologically sulfidated mZVI remain unclear. Therefore， this study investigated the effects of mZVI particle size and sulfate concentration on the efficiency of TCE removal by biologically sulfidated mZVI with different particle sizes， and explored the underlying mechanisms. The results showed that the mZVI particle size significantly affected the biological sulfidation efficiency and TCE removal rate. 7 μm ZVI exhibited the fastest removal rate （0.16 d-1） due to its larger specific surface area. However， it was prone to agglomeration and might inhibit microbial growth， leading to the lowest degree of biological sulfidation. In contrast， 40 μm ZVI showed the highest content of reductive sulfur （81.92%） after biological sulfidation， and its reactivity was significantly better than that of the chemically sulfidated group with the same particle size， indicating that biological sulfidation was more effective for larger-sized mZVI. Additionally， sulfate concentration had a significant impact on the dechlorination performance of mZVI. The increase in sulfate concentration created a favorable environment for the growth of sulfate-reducing bacteria， increased the content of reductive sulfur on the mZVI surface， and thus enhanced the dechlorination efficiency of S-mZVI. When the sulfate concentration reached 700 mg/L， S-mZVI could completely remove TCE within 24 days. The dechlorination product results showed that the sulfate concentration was positively correlated with the degree of dechlorination， and high sulfate concentrations promoted the complete removal of chlorine atoms from TCE molecules. The findings can provide theoretical guidance and technical support for the bio-sulfidated mZVI remediation of TCE-contaminated groundwater.
2026, 44(2): 78-84.
doi: 10.13205/j.hjgc.202602009
Abstract:
Aiming at the problems of complex seafloor environment where litter targets present multi-scale morphological distribution， inter-class ambiguity， due to high similarity with marine organisms' features， and the resulting issues of insufficient feature extraction capability， poor detection accuracy， and inaccurate localization， a seabed litter target detection algorithm based on the improved YOLOv8 was proposed. First， the ODConv full-dimensional dynamic convolution plus was fused into the C2f of the neck network， to form a new module C2f_ODConv， which enables the model to realize all-round dynamic adjustment of the convolution kernel and more finely adapt to the features of the input data， thus improving the effectiveness of the feature extraction； second， a deformable attention was introduced after the C2f_ODConv， which effectively captured local details in the image and improves the model detection accuracy； finally， UIoU Loss was used instead of CIoU Loss and a linear recession strategy was adopted to localize the target and improve the model generalization ability further accurately. Experiments were conducted on the public dataset TrashCan-Instance， and the experimental results showed that the improved model had a Recall and mAP of 64.4% and 70.4% respectively， which were 4.5 and 2.2 percentage points higher than the baseline model YOLOv8， and also met the underwater spam detection demand.
Aiming at the problems of complex seafloor environment where litter targets present multi-scale morphological distribution， inter-class ambiguity， due to high similarity with marine organisms' features， and the resulting issues of insufficient feature extraction capability， poor detection accuracy， and inaccurate localization， a seabed litter target detection algorithm based on the improved YOLOv8 was proposed. First， the ODConv full-dimensional dynamic convolution plus was fused into the C2f of the neck network， to form a new module C2f_ODConv， which enables the model to realize all-round dynamic adjustment of the convolution kernel and more finely adapt to the features of the input data， thus improving the effectiveness of the feature extraction； second， a deformable attention was introduced after the C2f_ODConv， which effectively captured local details in the image and improves the model detection accuracy； finally， UIoU Loss was used instead of CIoU Loss and a linear recession strategy was adopted to localize the target and improve the model generalization ability further accurately. Experiments were conducted on the public dataset TrashCan-Instance， and the experimental results showed that the improved model had a Recall and mAP of 64.4% and 70.4% respectively， which were 4.5 and 2.2 percentage points higher than the baseline model YOLOv8， and also met the underwater spam detection demand.
2026, 44(2): 85-91.
doi: 10.13205/j.hjgc.202602010
Abstract:
Intrinsic kinetic constants are very important for biogeochemical process simulation and environmental management engineering design. However， the intricate mass transfer-reaction coupling effects in sediments lead to the acquisition of apparent kinetic constants in conventional studies， with the underlying environmental dependency mechanisms remaining poorly resolved. This study systematically investigated the drivers of apparent kinetic phenomena through integrated laboratory column experiments and numerical simulations， anchored in diffusion boundary layer theory. Flow-through sediment reactors experiment and inversion results showed that the denitrification kinetic constants increased nonlinearly with the influent concentration and flow rate， showing a significant apparent kinetic phenomenon. When Da was not much less than 1， the reaction system often exhibited an apparent kinetic phenomenon； the increase of kinetic constants caused by changes in influent concentration and flow rate was due to the increase of the diffusion flux of nitrate nitrogen. But the specific reasons were different between the two conditions. The increase of kinetic constants from influent concentrations was due to the increase in concentration difference of nitrate at both sides of the diffusive boundary layer， while the increase of constants caused by flow rates was due to the thinner boundary layer. In order to avoid the simulation error caused by the misuse of kinetic constants， it is necessary to identify the apparent kinetic phenomena before simulations.
Intrinsic kinetic constants are very important for biogeochemical process simulation and environmental management engineering design. However， the intricate mass transfer-reaction coupling effects in sediments lead to the acquisition of apparent kinetic constants in conventional studies， with the underlying environmental dependency mechanisms remaining poorly resolved. This study systematically investigated the drivers of apparent kinetic phenomena through integrated laboratory column experiments and numerical simulations， anchored in diffusion boundary layer theory. Flow-through sediment reactors experiment and inversion results showed that the denitrification kinetic constants increased nonlinearly with the influent concentration and flow rate， showing a significant apparent kinetic phenomenon. When Da was not much less than 1， the reaction system often exhibited an apparent kinetic phenomenon； the increase of kinetic constants caused by changes in influent concentration and flow rate was due to the increase of the diffusion flux of nitrate nitrogen. But the specific reasons were different between the two conditions. The increase of kinetic constants from influent concentrations was due to the increase in concentration difference of nitrate at both sides of the diffusive boundary layer， while the increase of constants caused by flow rates was due to the thinner boundary layer. In order to avoid the simulation error caused by the misuse of kinetic constants， it is necessary to identify the apparent kinetic phenomena before simulations.
2026, 44(2): 92-102.
doi: 10.13205/j.hjgc.202602011
Abstract:
Chali Co Lake is a high-altitude （4650 m） carbonate-salt lake located in the Qinghai-Tibet Plateau. The community structure composition of bacteria and archaea involved is still unclear. This study employed high-throughput Illumina sequencing to analyze the diversity of bacteria and archaea in Chali Co Lake. By a 97% similarity level， operational taxonomic units （OTUs） were noted and analyzed based on the phylum， class， order， and genus level， respectively. The Redundancy analysis （RDA） was employed to examine the relationship between the dominant genus and environmental factors. A total of 37 phyla， 54 classes， 78 orders， and 417 genera （1，678 OTUs） of bacteria， and 10 phyla， 9 classes， 15 orders， and 32 genera （526 OTUs） of archaea were identified. The predominant bacterial genus were Pelobacter （4.60% to 9.58%）， Aquiflexum （1.08% to 13.97%）， Desulfurivibrio （0.64% to 8.07%） and Desulfocapsa （6.87%）； The dominant archaeota genera were Woesearchaeota AR16 （72.60% to 86.31%）、AR18 （2.71% to 6.45%） and AR15 （0.26% to 6.19%）. Significant correlation between the bacterial community structure and the concentrations of TS， HCO3-， and SO42- （P<0.05）. Pelobacter exhibited a significant correlation with T， TN， and Na+ concentrations. Aquiflexum demonstrated a significant correlation with TOC， TN， and temperature. Additionally， both Desulfurivibrio and Desulfocapsa exhibited correlations with temperature， SO42-， and HCO3- concentrations. The structure of archaeal communities was most strongly correlated with K+， TS， and pH. The dominant genera AR16 and AR18 subgroups of archaea exhibited a significant correlation with TP， Mg2+， and K+. The AR15 subgroup demonstrated a significant correlation with TOC， TN， and SO42-. This study revealed the community structure of bacteria and archaea and their species diversity in Chali Co Lake， and provided a theoretical basis for developing halophilic bacteria and exploiting microbial resources.
Chali Co Lake is a high-altitude （4650 m） carbonate-salt lake located in the Qinghai-Tibet Plateau. The community structure composition of bacteria and archaea involved is still unclear. This study employed high-throughput Illumina sequencing to analyze the diversity of bacteria and archaea in Chali Co Lake. By a 97% similarity level， operational taxonomic units （OTUs） were noted and analyzed based on the phylum， class， order， and genus level， respectively. The Redundancy analysis （RDA） was employed to examine the relationship between the dominant genus and environmental factors. A total of 37 phyla， 54 classes， 78 orders， and 417 genera （1，678 OTUs） of bacteria， and 10 phyla， 9 classes， 15 orders， and 32 genera （526 OTUs） of archaea were identified. The predominant bacterial genus were Pelobacter （4.60% to 9.58%）， Aquiflexum （1.08% to 13.97%）， Desulfurivibrio （0.64% to 8.07%） and Desulfocapsa （6.87%）； The dominant archaeota genera were Woesearchaeota AR16 （72.60% to 86.31%）、AR18 （2.71% to 6.45%） and AR15 （0.26% to 6.19%）. Significant correlation between the bacterial community structure and the concentrations of TS， HCO3-， and SO42- （P<0.05）. Pelobacter exhibited a significant correlation with T， TN， and Na+ concentrations. Aquiflexum demonstrated a significant correlation with TOC， TN， and temperature. Additionally， both Desulfurivibrio and Desulfocapsa exhibited correlations with temperature， SO42-， and HCO3- concentrations. The structure of archaeal communities was most strongly correlated with K+， TS， and pH. The dominant genera AR16 and AR18 subgroups of archaea exhibited a significant correlation with TP， Mg2+， and K+. The AR15 subgroup demonstrated a significant correlation with TOC， TN， and SO42-. This study revealed the community structure of bacteria and archaea and their species diversity in Chali Co Lake， and provided a theoretical basis for developing halophilic bacteria and exploiting microbial resources.
2026, 44(2): 103-111.
doi: 10.13205/j.hjgc.202602012
Abstract:
Aiming at efficiently removing NO x and N2O from the tail gas of nitric acid production， a technique route of catalytic reduction of NO x followed by catalytic decomposition of N2O was proposed. NO x reduction over V2O5/TiO2 catalyst and N2O decomposition over Co3O4-based catalysts were separately investigated. The combined removal of NO x and N2O was then investigated by connecting the V2O5/TiO2 catalyst with the optimized 2.0Cs/Co3O4 catalyst in series. Physicochemical characteristics of the catalysts were characterized by N2 adsorption-desorption， XRD， XPS， and O2-TPD techniques. The results showed that， for NO x reduction over the V2O5/TiO2 catalyst， the presence of 2% H2O in the feed gas could broaden the active temperature window of the catalyst， improve the N2 selectivity， and inhibit the formation of N2O. By loading 2.0% Cs on Co3O4， the N2O decomposition was greatly improved， which might be explained by the reduction of some Co3+ to Co2+ and the formation of more oxygen vacancies on the catalyst surface， due to the introduction of Cs. At high temperatures （400 ℃）. the presence of 2.0% H2O in the feed gas showed weak inhibitory effects on the decomposition of N2O over the 2.0Cs/Co3O4 catalyst， while the coexistence of 2% H2O and 50×10-6 NO significantly deactivated the 2.0Cs/Co3O4 catalyst. When the two-stage catalyst， consisting of upstream V2O5/TiO2 and downstream 2.0Cs/Co3O4 catalyst， was used to remove NO x and N2O， NO x was mainly reduced over the V2O5/TiO2 catalyst， with limited influence from the presence of N2O. In the temperature range for efficient removal of NO x （and NH3） over the V2O5/TiO2 catalyst， N2O could be stably decomposed over the downstream 2.0Cs/Co3O4 catalyst. With 2% H2O contained in the feed gas， complete conversion of NO x and NH3 was achieved at 400 ℃， whereas the conversion of N2O reached 61.3%.
Aiming at efficiently removing NO x and N2O from the tail gas of nitric acid production， a technique route of catalytic reduction of NO x followed by catalytic decomposition of N2O was proposed. NO x reduction over V2O5/TiO2 catalyst and N2O decomposition over Co3O4-based catalysts were separately investigated. The combined removal of NO x and N2O was then investigated by connecting the V2O5/TiO2 catalyst with the optimized 2.0Cs/Co3O4 catalyst in series. Physicochemical characteristics of the catalysts were characterized by N2 adsorption-desorption， XRD， XPS， and O2-TPD techniques. The results showed that， for NO x reduction over the V2O5/TiO2 catalyst， the presence of 2% H2O in the feed gas could broaden the active temperature window of the catalyst， improve the N2 selectivity， and inhibit the formation of N2O. By loading 2.0% Cs on Co3O4， the N2O decomposition was greatly improved， which might be explained by the reduction of some Co3+ to Co2+ and the formation of more oxygen vacancies on the catalyst surface， due to the introduction of Cs. At high temperatures （400 ℃）. the presence of 2.0% H2O in the feed gas showed weak inhibitory effects on the decomposition of N2O over the 2.0Cs/Co3O4 catalyst， while the coexistence of 2% H2O and 50×10-6 NO significantly deactivated the 2.0Cs/Co3O4 catalyst. When the two-stage catalyst， consisting of upstream V2O5/TiO2 and downstream 2.0Cs/Co3O4 catalyst， was used to remove NO x and N2O， NO x was mainly reduced over the V2O5/TiO2 catalyst， with limited influence from the presence of N2O. In the temperature range for efficient removal of NO x （and NH3） over the V2O5/TiO2 catalyst， N2O could be stably decomposed over the downstream 2.0Cs/Co3O4 catalyst. With 2% H2O contained in the feed gas， complete conversion of NO x and NH3 was achieved at 400 ℃， whereas the conversion of N2O reached 61.3%.
2026, 44(2): 112-121.
doi: 10.13205/j.hjgc.202602013
Abstract:
To improve the practical engineering application effect of the wet electrostatic precipitator for the gas from a certain converter outlet cabinet， the internal flow field of the wet electrostatic precipitator was simulated and analyzed through COMSOL Multiphysics， and its dust removal performance and volt-ampere characteristic curves under different working conditions were predicted. The results showed that after optimizing the airflow distribution， the root mean square of the airflow at the inlet section of the electric field was 0.159， and the total pressure difference between the inlet and outlet of the electrostatic precipitator was 205 Pa， which met the emission standard requirements. When the inlet particle concentration was 100 mg/Nm3 and 150 mg/Nm3， respectively， the wet electrostatic precipitator should be ensured to operate under an external voltage of 30 kV and 35 kV or above， so that the outlet particle concentration could meet the requirements of gas users' usage standards. Under the condition of an applied voltage of 30 to 45 kV， the line current density can be taken within the range of 0.048 to 0.149 mA/m. Through on-site measurement， the numerical simulation results were in good agreement with the measured results. This study can provide a reference for the selection and design of wet electrostatic precipitators and their power sources for converter discharge gas.
To improve the practical engineering application effect of the wet electrostatic precipitator for the gas from a certain converter outlet cabinet， the internal flow field of the wet electrostatic precipitator was simulated and analyzed through COMSOL Multiphysics， and its dust removal performance and volt-ampere characteristic curves under different working conditions were predicted. The results showed that after optimizing the airflow distribution， the root mean square of the airflow at the inlet section of the electric field was 0.159， and the total pressure difference between the inlet and outlet of the electrostatic precipitator was 205 Pa， which met the emission standard requirements. When the inlet particle concentration was 100 mg/Nm3 and 150 mg/Nm3， respectively， the wet electrostatic precipitator should be ensured to operate under an external voltage of 30 kV and 35 kV or above， so that the outlet particle concentration could meet the requirements of gas users' usage standards. Under the condition of an applied voltage of 30 to 45 kV， the line current density can be taken within the range of 0.048 to 0.149 mA/m. Through on-site measurement， the numerical simulation results were in good agreement with the measured results. This study can provide a reference for the selection and design of wet electrostatic precipitators and their power sources for converter discharge gas.
2026, 44(2): 122-129.
doi: 10.13205/j.hjgc.202602014
Abstract:
Electrical precipitators in the sintering plants are facing with the excessive emission of particulate beyond the standard limit， and the new type of porous dust collecting plate can promote the overall dust removal performance， to achieve the ultra-low emissions of sintering plants. The article first conducted a sampling and analysis of sintering ash in industrial electrostatic precipitators， and then used COMSOL Multiphysics to study the electric field and flow field within the dust collection areas of two types of plate shapes. Finally， based on the ash sampling results， it simulated and predicted the dust collection performance. The dust removal performance of the new porous plate electric dust collector was verified by practical engineering cases. The results showed that the collection efficiency of the electrostatic dust precipitator in the flue gas was low when the dust was in the range of 0.01 to 10 μm. The collected dust contained more than 50% Fe and its oxide， which had a certain regeneration value. The overall specific resistance of the dust was about 1012 Ω·cm.
Electrical precipitators in the sintering plants are facing with the excessive emission of particulate beyond the standard limit， and the new type of porous dust collecting plate can promote the overall dust removal performance， to achieve the ultra-low emissions of sintering plants. The article first conducted a sampling and analysis of sintering ash in industrial electrostatic precipitators， and then used COMSOL Multiphysics to study the electric field and flow field within the dust collection areas of two types of plate shapes. Finally， based on the ash sampling results， it simulated and predicted the dust collection performance. The dust removal performance of the new porous plate electric dust collector was verified by practical engineering cases. The results showed that the collection efficiency of the electrostatic dust precipitator in the flue gas was low when the dust was in the range of 0.01 to 10 μm. The collected dust contained more than 50% Fe and its oxide， which had a certain regeneration value. The overall specific resistance of the dust was about 1012 Ω·cm.
2026, 44(2): 130-140.
doi: 10.13205/j.hjgc.202602015
Abstract:
The degradation of chlorinated volatile organic compounds （CVOCs） in a wet scrubber using ozone （O3） is primarily limited by the gas-liquid mass transfer efficiencies of O3 and CVOCs. In this research， a catalyst prepared by loading ferrous oxide onto activated carbon， named Fe-C， was used to boost the gas-liquid mass transfer of O3 and a typical CVOCs specie， chlorobenzene （CB）. The effects of Fe-C dosage， inlet concentration， and gas flow rate on the mass transfer of O3 and CB were investigated， and the mechanism of the simultaneous mass transfer of O3 and CB enhanced by Fe-C was revealed. The results showed that injecting O3 or CB into the wet scrubber alone caused the mass transfer coefficients to increase with the inlet concentration， and these coefficients initially rose and then decreased as the Fe-C dosage and gas flow rate increased. For both O3 and CB， the best mass transfer effect was achieved with an Fe-C dosage of 2.0 g/L and a gas flow rate of 500 mL/min. The mass transfer enhancement factors of O3 and CB were 19.73 and 10.91， respectively， at the Fe-C dosage of 2.0 g/L. When O3 and CB were simultaneously fed into the wet scrubber， the mass transfer of CB was further enhanced， and the CB mass transfer enhancement factor E could reach 12.87 at the Fe-C dosage of 2.0 g/L. The shuttle effect of Fe-C enhanced the mass transfer of CB and O3 between gas and liquid phases. Through converting O3 into ·OH and ·O2-， the Fe-C catalyst promoted the degradation of CB in the solution.
The degradation of chlorinated volatile organic compounds （CVOCs） in a wet scrubber using ozone （O3） is primarily limited by the gas-liquid mass transfer efficiencies of O3 and CVOCs. In this research， a catalyst prepared by loading ferrous oxide onto activated carbon， named Fe-C， was used to boost the gas-liquid mass transfer of O3 and a typical CVOCs specie， chlorobenzene （CB）. The effects of Fe-C dosage， inlet concentration， and gas flow rate on the mass transfer of O3 and CB were investigated， and the mechanism of the simultaneous mass transfer of O3 and CB enhanced by Fe-C was revealed. The results showed that injecting O3 or CB into the wet scrubber alone caused the mass transfer coefficients to increase with the inlet concentration， and these coefficients initially rose and then decreased as the Fe-C dosage and gas flow rate increased. For both O3 and CB， the best mass transfer effect was achieved with an Fe-C dosage of 2.0 g/L and a gas flow rate of 500 mL/min. The mass transfer enhancement factors of O3 and CB were 19.73 and 10.91， respectively， at the Fe-C dosage of 2.0 g/L. When O3 and CB were simultaneously fed into the wet scrubber， the mass transfer of CB was further enhanced， and the CB mass transfer enhancement factor E could reach 12.87 at the Fe-C dosage of 2.0 g/L. The shuttle effect of Fe-C enhanced the mass transfer of CB and O3 between gas and liquid phases. Through converting O3 into ·OH and ·O2-， the Fe-C catalyst promoted the degradation of CB in the solution.
2026, 44(2): 141-149.
doi: 10.13205/j.hjgc.202602016
Abstract:
Through comparing the technical application and carbon emissions of in-situ and ex-situ gas thermal desorption technology in the remediation process of contaminated sites， the application trend of thermal desorption technology in future site remediation is comprehensively analyzed， and suggestions are provided for innovation and improvement of the technology under the requirements of green low-carbon remediation. The study showed that the amount of mechanical input in the ex-situ gas thermal desorption remediation process is higher than that of in-situ gas thermal desorption technology； however， the number of equipment input is lower than that of in-situ technology. The main energy consumption and carbon emission sources of this technology are gas， diesel， and electricity. According to the process data of four contaminated projects in China， the carbon emissions were calculated. The carbon emission per cubic contaminated soil repaired by thermal desorption technology was in the range of 170.74 to 373.25 kg CO2-eq. The carbon emissions of each cubic contaminated soil remediated by in-situ gas thermal desorption technology were lower than those of ex-situ gas thermal desorption technology. The proportions of carbon emissions of materials used in the remediation process for in-situ gas thermal desorption technology were in the order of natural gas>steel>concrete>electricity>NaOH>others； for the ex-situ gas thermal desorption technology， the order was natural gas>quicklime>concrete>electricity>diesel>others. To achieve the goal of green low-carbon restoration， pollution reduction， and carbon reduction， the following methods can be adopted： selecting the specific parameters of thermal desorption technology， optimizing the energy supply structure， upgrading or innovating the research and development of thermal desorption equipment， and combining thermal desorption technology with other technologies.
Through comparing the technical application and carbon emissions of in-situ and ex-situ gas thermal desorption technology in the remediation process of contaminated sites， the application trend of thermal desorption technology in future site remediation is comprehensively analyzed， and suggestions are provided for innovation and improvement of the technology under the requirements of green low-carbon remediation. The study showed that the amount of mechanical input in the ex-situ gas thermal desorption remediation process is higher than that of in-situ gas thermal desorption technology； however， the number of equipment input is lower than that of in-situ technology. The main energy consumption and carbon emission sources of this technology are gas， diesel， and electricity. According to the process data of four contaminated projects in China， the carbon emissions were calculated. The carbon emission per cubic contaminated soil repaired by thermal desorption technology was in the range of 170.74 to 373.25 kg CO2-eq. The carbon emissions of each cubic contaminated soil remediated by in-situ gas thermal desorption technology were lower than those of ex-situ gas thermal desorption technology. The proportions of carbon emissions of materials used in the remediation process for in-situ gas thermal desorption technology were in the order of natural gas>steel>concrete>electricity>NaOH>others； for the ex-situ gas thermal desorption technology， the order was natural gas>quicklime>concrete>electricity>diesel>others. To achieve the goal of green low-carbon restoration， pollution reduction， and carbon reduction， the following methods can be adopted： selecting the specific parameters of thermal desorption technology， optimizing the energy supply structure， upgrading or innovating the research and development of thermal desorption equipment， and combining thermal desorption technology with other technologies.
2026, 44(2): 150-157.
doi: 10.13205/j.hjgc.202602017
Abstract:
Electrocatalytic reduction of CO2 （eCO2RR） is a crucial pathway for China to achieve its "Carbon Peak and Carbon Neutrality" goals. Graphitic carbon nitride （g-C3N4） is widely employed as a catalyst or catalyst support in electrocatalysis due to its abundant raw materials， simple preparation process， and low cost. However， g-C3N4， when used as a catalyst support for eCO2RR， faces bottlenecks such as low specific surface area， weak alkalinity， and competitive reduction of low-concentration CO2 and O2 in actual flue gas. Therefore， this study proposed a modification strategy for SnO2/g-C3N4 composite catalysts through alkali-thermal treatment. Characterization techniques such as XPS and CO2-TPD revealed that the alkali-thermal treatment significantly increased the surface amino group content of the g-C3N4 support （from 3.7% to 7.0%）， enhancing the overall alkalinity and CO2 adsorption capacity of the catalyst （from 7.69 mmol/g to 48.80 mmol/g）. This treatment accelerated electron transfer from N atoms in g-C3N4 to Sn active sites， forming electron-rich Sn centers and generating more oxygen vacancies. These effects synergistically promoted the activation and reduction of CO2. Competitive adsorption experiments demonstrated that SnO2/CNOHHT exhibited a higher adsorption capacity for CO2 than for O2 in a CO2/O2 mixture （with a separation factor of 0.90）. This selectivity favors the formation of a CO2-enriched microenvironment at the reaction interface， thereby suppressing the competitive oxygen reduction reaction （ORR）. Electrocatalytic performance tests showed that under a pure CO2 atmosphere， SnO2/CNOHHT achieved a high Faradaic efficiency （FE） of 80.5% for formate production at a current density of 23.5 mA/cm2. Remarkably， in a simulated flue gas atmosphere containing 4% O2， it still maintained a FE for formate of 59.4%， significantly outperforming both the unmodified and the alkali-treated-only catalysts. This study provides new insight for developing g-C3N4-based eCO2RR catalysts suitable for practical oxygen-containing flue gas conditions.
Electrocatalytic reduction of CO2 （eCO2RR） is a crucial pathway for China to achieve its "Carbon Peak and Carbon Neutrality" goals. Graphitic carbon nitride （g-C3N4） is widely employed as a catalyst or catalyst support in electrocatalysis due to its abundant raw materials， simple preparation process， and low cost. However， g-C3N4， when used as a catalyst support for eCO2RR， faces bottlenecks such as low specific surface area， weak alkalinity， and competitive reduction of low-concentration CO2 and O2 in actual flue gas. Therefore， this study proposed a modification strategy for SnO2/g-C3N4 composite catalysts through alkali-thermal treatment. Characterization techniques such as XPS and CO2-TPD revealed that the alkali-thermal treatment significantly increased the surface amino group content of the g-C3N4 support （from 3.7% to 7.0%）， enhancing the overall alkalinity and CO2 adsorption capacity of the catalyst （from 7.69 mmol/g to 48.80 mmol/g）. This treatment accelerated electron transfer from N atoms in g-C3N4 to Sn active sites， forming electron-rich Sn centers and generating more oxygen vacancies. These effects synergistically promoted the activation and reduction of CO2. Competitive adsorption experiments demonstrated that SnO2/CNOHHT exhibited a higher adsorption capacity for CO2 than for O2 in a CO2/O2 mixture （with a separation factor of 0.90）. This selectivity favors the formation of a CO2-enriched microenvironment at the reaction interface， thereby suppressing the competitive oxygen reduction reaction （ORR）. Electrocatalytic performance tests showed that under a pure CO2 atmosphere， SnO2/CNOHHT achieved a high Faradaic efficiency （FE） of 80.5% for formate production at a current density of 23.5 mA/cm2. Remarkably， in a simulated flue gas atmosphere containing 4% O2， it still maintained a FE for formate of 59.4%， significantly outperforming both the unmodified and the alkali-treated-only catalysts. This study provides new insight for developing g-C3N4-based eCO2RR catalysts suitable for practical oxygen-containing flue gas conditions.
2026, 44(2): 158-168.
doi: 10.13205/j.hjgc.202602018
Abstract:
Road traffic noise pollution has become increasingly severe in urban areas. Unlike traditional fuel-powered vehicles， new energy vehicles （NEVs） rely on distinct power sources， endowing them with inherent noise reduction advantages during operation. However， the specific improvement effect of NEV adoption on the quality of the urban traffic sound environment remains unclear. Based on real-time road traffic noise monitoring data collected in the urban area of Suzhou from 2020 to 2023， this study employs ArcGIS spatial analysis， grey correlation analysis， and other methods to systematically evaluate the impact of NEV penetration on the spatiotemporal characteristics of road traffic noise pollution and its mitigation effects. The results indicate that： 1） The nighttime noise compliance rate is significantly lower than that during daytime； the annual noise trough and peak occur in February and July， respectively. Traffic noise is closely correlated with motor vehicle activity—peak-hour noise levels exhibit minimal fluctuations， while non-peak-hour noise values show a gradual downward trend. Nighttime noise exceedance periods are concentrated around 22：00 and 04：00—06：00. 2） Noise pollution is most severe on arterial and secondary roads， commercial hubs， and roads adjacent to university towns， whereas scenic areas and residential districts experience relatively mild pollution. 3） Traffic congestion is identified as a key contributing factor to noise pollution. With the continuous increase in NEV penetration， non-peak-hour traffic noise has decreased significantly， demonstrating the positive mitigation effect of NEVs on traffic noise during this period.
Road traffic noise pollution has become increasingly severe in urban areas. Unlike traditional fuel-powered vehicles， new energy vehicles （NEVs） rely on distinct power sources， endowing them with inherent noise reduction advantages during operation. However， the specific improvement effect of NEV adoption on the quality of the urban traffic sound environment remains unclear. Based on real-time road traffic noise monitoring data collected in the urban area of Suzhou from 2020 to 2023， this study employs ArcGIS spatial analysis， grey correlation analysis， and other methods to systematically evaluate the impact of NEV penetration on the spatiotemporal characteristics of road traffic noise pollution and its mitigation effects. The results indicate that： 1） The nighttime noise compliance rate is significantly lower than that during daytime； the annual noise trough and peak occur in February and July， respectively. Traffic noise is closely correlated with motor vehicle activity—peak-hour noise levels exhibit minimal fluctuations， while non-peak-hour noise values show a gradual downward trend. Nighttime noise exceedance periods are concentrated around 22：00 and 04：00—06：00. 2） Noise pollution is most severe on arterial and secondary roads， commercial hubs， and roads adjacent to university towns， whereas scenic areas and residential districts experience relatively mild pollution. 3） Traffic congestion is identified as a key contributing factor to noise pollution. With the continuous increase in NEV penetration， non-peak-hour traffic noise has decreased significantly， demonstrating the positive mitigation effect of NEVs on traffic noise during this period.
2026, 44(2): 169-178.
doi: 10.13205/j.hjgc.202602019
Abstract:
Air pollution poses serious challenges to both the environment and human health. Influenced by individual sensory characteristics （such as visual sense） and environmental context （such as visibility）， the public often struggles to accurately assess air pollution risk levels. By integrating textual semantic analysis with decoupling theory， this study proposed a novel Public Air Pollution Risk Perception Bias Index to quantify the gap between subjective risk perception and actual risk levels， taking Chengdu as a case study for empirical analysis. Results showed that： 1） In the years with more frequent air pollution warnings and the autumn and winter seasons with more severe air pollution， the number of air pollution-related texts peaked， indicating heightened public concern during these periods. 2） There are seasonal differences in the public’s subjective risk perception scores of air pollution， with average values of -1.5 in autumn and winter， and 4.9 in spring and summer. This indicates that the public subjectively perceives air pollution to pose greater health risks during autumn and winter seasons. 3） A discrepancy existed between the public’s subjective risk perception and the actual risk levels， with both overestimation and underestimation occurring. In autumn and winter， due to the more direct and intense sensory impact of pollutants， which mainly consisted of particulate matter such as PM2.5 and PM10， the proportion of overestimating the risk （26.9%） was significantly higher than that in spring and summer （15.1%）. 4） On the one hand， regulatory authorities should develop differentiated pollutant control strategies based on the seasonal characteristics of pollution； On the other hand， they should strengthen public awareness and accurate understanding of air pollution risks through information dissemination and public education.
Air pollution poses serious challenges to both the environment and human health. Influenced by individual sensory characteristics （such as visual sense） and environmental context （such as visibility）， the public often struggles to accurately assess air pollution risk levels. By integrating textual semantic analysis with decoupling theory， this study proposed a novel Public Air Pollution Risk Perception Bias Index to quantify the gap between subjective risk perception and actual risk levels， taking Chengdu as a case study for empirical analysis. Results showed that： 1） In the years with more frequent air pollution warnings and the autumn and winter seasons with more severe air pollution， the number of air pollution-related texts peaked， indicating heightened public concern during these periods. 2） There are seasonal differences in the public’s subjective risk perception scores of air pollution， with average values of -1.5 in autumn and winter， and 4.9 in spring and summer. This indicates that the public subjectively perceives air pollution to pose greater health risks during autumn and winter seasons. 3） A discrepancy existed between the public’s subjective risk perception and the actual risk levels， with both overestimation and underestimation occurring. In autumn and winter， due to the more direct and intense sensory impact of pollutants， which mainly consisted of particulate matter such as PM2.5 and PM10， the proportion of overestimating the risk （26.9%） was significantly higher than that in spring and summer （15.1%）. 4） On the one hand， regulatory authorities should develop differentiated pollutant control strategies based on the seasonal characteristics of pollution； On the other hand， they should strengthen public awareness and accurate understanding of air pollution risks through information dissemination and public education.
2026, 44(2): 179-187.
doi: 10.13205/j.hjgc.202602020
Abstract:
This paper presents a comprehensive review of the evolutionary development of global landfill liner systems. It elaborates on the critical and prevalent issue of liner system leakage， while analyzing the complex interactions and coupled effects of multiple contributing factors to such failures. It surveys the current mainstream leakage detection technologies for landfill liners， classifying them into three distinct categories based on their evolutionary trajectory： single electromagnetic technologies， synergistic multi-geophysical technologies， and in-situ real-time monitoring technologies （note： "in-situ" and "real-time" are hyphenated only when used as compound adjectives）. For each category， a thorough summary is provided， covering representative methods， typical application scenarios， and core advantages and disadvantages. Furthermore， This paper articulates the prevailing challenges encountered in practical applications and proposes substantive future research directions. As a key contribution， it provides the first integrated analysis of various applied case studies to critically evaluate and illustrate the practical effectiveness and inherent limitations of these three technology types when deployed in real-world scenarios. By synthesizing insights from the root causes of liner leakage， the challenges in practical applications， and the specific problems revealed by case studies， three strategic future directions are proposed. First， deepen and advance "synergistic multi-geophysical technologies" to realize a paradigm shift from conventional data fusion to intelligent predictive modeling. Second， focus on the research and development of non-contact and minimally invasive survey technologies to explore feasible pathways for effective monitoring of aging and legacy landfills. Third， actively promote the development of low-cost and networked leakage detection technologies， aiming to significantly lower the threshold for long-term monitoring and enhance risk management for the vast number of existing landfill sites.
This paper presents a comprehensive review of the evolutionary development of global landfill liner systems. It elaborates on the critical and prevalent issue of liner system leakage， while analyzing the complex interactions and coupled effects of multiple contributing factors to such failures. It surveys the current mainstream leakage detection technologies for landfill liners， classifying them into three distinct categories based on their evolutionary trajectory： single electromagnetic technologies， synergistic multi-geophysical technologies， and in-situ real-time monitoring technologies （note： "in-situ" and "real-time" are hyphenated only when used as compound adjectives）. For each category， a thorough summary is provided， covering representative methods， typical application scenarios， and core advantages and disadvantages. Furthermore， This paper articulates the prevailing challenges encountered in practical applications and proposes substantive future research directions. As a key contribution， it provides the first integrated analysis of various applied case studies to critically evaluate and illustrate the practical effectiveness and inherent limitations of these three technology types when deployed in real-world scenarios. By synthesizing insights from the root causes of liner leakage， the challenges in practical applications， and the specific problems revealed by case studies， three strategic future directions are proposed. First， deepen and advance "synergistic multi-geophysical technologies" to realize a paradigm shift from conventional data fusion to intelligent predictive modeling. Second， focus on the research and development of non-contact and minimally invasive survey technologies to explore feasible pathways for effective monitoring of aging and legacy landfills. Third， actively promote the development of low-cost and networked leakage detection technologies， aiming to significantly lower the threshold for long-term monitoring and enhance risk management for the vast number of existing landfill sites.
2026, 44(2): 188-199.
doi: 10.13205/j.hjgc.202602021
Abstract:
Schwertmannite （Sch）， a typical sulfate mineral commonly found in mine drainage environment， plays a crucial role in the geochemical cycling of heavy metals. Due to its unique surface complexation sites and isomorphic substitution properties， Sch exhibits a strong affinity for immobilizing antimony （Sb）， thereby influencing Sb mobility and bioavailability in mining-impacted environment. Sulfate-reducing bacteria （SRB） play a key role in the biogeochemical transformation of sulfur and metals through sulfate reduction， a process that induces mineral phase transformations and regulates the migration and redistribution of heavy metals. However， the specific interfacial reaction mechanisms between SRB and Sb-bearing Sch （Sb-Sch） remain poorly understood， particularly under varying pH conditions. In this study， a controlled reaction system involving SRB and Sb-Sch was established to systematically investigate the phase transformation of Sb-Sch and the associated Sb redistribution mechanisms under different initial pH conditions. By integrating advanced mineralogical （such as XRD， SEM-EDS， and FTIR） and microbiology （16S rRNA） characterization techniques， this study provides a comprehensive insight into the pathways governing Sb-Sch transformation in biologically active environments. The major findings of this research were as follows： 1） SRB-driven dissolution and recrystallization processes： the coupled effects of proton secretion and sulfate reduction significantly enhanced the dissolution of Sb-Sch and the subsequent precipitation of secondary mineral phases. The primary secondary mineral formed was mackinawite， a common product of biogenic iron-sulfide precipitation. Additionally， distinct Sb-bearing mineral phases were formed under different pH conditions： in acidic environments， berthierite was the predominant Sb-bearing phase； in neutral conditions， stibnite was observed； whereas under alkaline conditions， kermesite was identified as the primary Sb mineral phase. 2） Sb speciation transformations and immobilization mechanisms： during Sb-Sch dissolution， the released Sb（V） was subjected to electron transfer processes at the microbe-mineral interface， leading to its reduction to Sb（Ⅲ）. The reduced Sb（Ⅲ） exhibited dual immobilization pathways： a portion was sequestered through surface adsorption onto newly formed iron sulfides and iron oxides， while another fraction complexed with sulfide （S2-）/ ferrous iron （Fe2+）， forming stable Fe/S-Sb minerals. 3） microbial community dynamics and functional contributions： microbial community analysis revealed significant variations in SRB composition and activity under different pH conditions， highlighting their functional roles in Sb-Sch transformation. In acidic and neutral environments， Desulfosporosinus was the dominant SRB genus， actively mediating sulfur， iron， and antimony redox transformations through enzymatic electron transfer pathways. Conversely， in alkaline conditions， Anaerostignum emerged as the most dominant genus， playing a pivotal role in Sb（Ⅲ） biomineralization processes. This pH-dependent shift in microbial dominance underscores the relationship between microbial metabolic activity， mineral phase transformations， and heavy metal sequestration in biogeochemical systems. These findings clarify microbe-mineral controls on Sb stability， guiding bioremediation to reduce contamination and provide theoretical and technical support for mining ecological restoration.
Schwertmannite （Sch）， a typical sulfate mineral commonly found in mine drainage environment， plays a crucial role in the geochemical cycling of heavy metals. Due to its unique surface complexation sites and isomorphic substitution properties， Sch exhibits a strong affinity for immobilizing antimony （Sb）， thereby influencing Sb mobility and bioavailability in mining-impacted environment. Sulfate-reducing bacteria （SRB） play a key role in the biogeochemical transformation of sulfur and metals through sulfate reduction， a process that induces mineral phase transformations and regulates the migration and redistribution of heavy metals. However， the specific interfacial reaction mechanisms between SRB and Sb-bearing Sch （Sb-Sch） remain poorly understood， particularly under varying pH conditions. In this study， a controlled reaction system involving SRB and Sb-Sch was established to systematically investigate the phase transformation of Sb-Sch and the associated Sb redistribution mechanisms under different initial pH conditions. By integrating advanced mineralogical （such as XRD， SEM-EDS， and FTIR） and microbiology （16S rRNA） characterization techniques， this study provides a comprehensive insight into the pathways governing Sb-Sch transformation in biologically active environments. The major findings of this research were as follows： 1） SRB-driven dissolution and recrystallization processes： the coupled effects of proton secretion and sulfate reduction significantly enhanced the dissolution of Sb-Sch and the subsequent precipitation of secondary mineral phases. The primary secondary mineral formed was mackinawite， a common product of biogenic iron-sulfide precipitation. Additionally， distinct Sb-bearing mineral phases were formed under different pH conditions： in acidic environments， berthierite was the predominant Sb-bearing phase； in neutral conditions， stibnite was observed； whereas under alkaline conditions， kermesite was identified as the primary Sb mineral phase. 2） Sb speciation transformations and immobilization mechanisms： during Sb-Sch dissolution， the released Sb（V） was subjected to electron transfer processes at the microbe-mineral interface， leading to its reduction to Sb（Ⅲ）. The reduced Sb（Ⅲ） exhibited dual immobilization pathways： a portion was sequestered through surface adsorption onto newly formed iron sulfides and iron oxides， while another fraction complexed with sulfide （S2-）/ ferrous iron （Fe2+）， forming stable Fe/S-Sb minerals. 3） microbial community dynamics and functional contributions： microbial community analysis revealed significant variations in SRB composition and activity under different pH conditions， highlighting their functional roles in Sb-Sch transformation. In acidic and neutral environments， Desulfosporosinus was the dominant SRB genus， actively mediating sulfur， iron， and antimony redox transformations through enzymatic electron transfer pathways. Conversely， in alkaline conditions， Anaerostignum emerged as the most dominant genus， playing a pivotal role in Sb（Ⅲ） biomineralization processes. This pH-dependent shift in microbial dominance underscores the relationship between microbial metabolic activity， mineral phase transformations， and heavy metal sequestration in biogeochemical systems. These findings clarify microbe-mineral controls on Sb stability， guiding bioremediation to reduce contamination and provide theoretical and technical support for mining ecological restoration.
2026, 44(2): 200-208.
doi: 10.13205/j.hjgc.202602022
Abstract:
Phytoremediation technology is considered to be one of the most promising remediation methods for complex contaminated soil. Leersia hexandra Swartz is a chromium hyperaccumulator first discovered and reported in China， and also a nickel and copper hyperaccumulator plant. Previous studies have been carried out on the physiological and molecular characteristics of chromium， nickel， and copper accumulation in L. hexandra. However， the rhizosphere process and the mechanism of symbiotic regulation of co-hyperaccumulation of chromium and nickel by L. hexandra remain unclear. Therefore， in this paper， L. hexandra was selected as the research object， and the spatiotemporal variation of pH value in rhizosphere microdomain under the heavy metal stress of chromium and nickel， and the influence on enzyme activity in the rhizosphere soil of L. hexandra were studied by using the planar optode technique and in-situ enzyme spectrometry. The results showed that： 1） under the stress of heavy metals chromium and nickel， the rhizosphere pH value of L. hexandra will be significantly reduced. The pH value of the soil around the rhizosphere in the CK group fluctuated between 6.57 and 7.13， but decreased sharply under the compound stress， and the pH value fluctuated between 6.00 and 6.57. Rhizosphere acidification is an important mechanism for the activation and absorption of heavy metals by hyperaccumulator plants， which may also be an important mechanism for the hyperaccumulation of chromium and nickel in L. hexandra. 2） The rhizosphere zone of L. hexandra was the hotspot of enzyme activity. Under the stress of chromium and nickel， the activity of β-glucosidase increased， and the activity of acid phosphatase decreased. The enzyme activity in the CK group fluctuated between 400 pmol/（cm2·h） and 600 pmol/（cm2·h）， while the enzyme activity in rhizosphere soil decreased to 200 to 400 pmol/（cm2·h） under heavy metal stress. These results indicated that the rhizosphere region of L. hexandra had a significant effect on enzyme activity under the stress of chromium and nickel， which may be related to the physiological mechanism of the rhizosphere of L. hexandra under stress.
Phytoremediation technology is considered to be one of the most promising remediation methods for complex contaminated soil. Leersia hexandra Swartz is a chromium hyperaccumulator first discovered and reported in China， and also a nickel and copper hyperaccumulator plant. Previous studies have been carried out on the physiological and molecular characteristics of chromium， nickel， and copper accumulation in L. hexandra. However， the rhizosphere process and the mechanism of symbiotic regulation of co-hyperaccumulation of chromium and nickel by L. hexandra remain unclear. Therefore， in this paper， L. hexandra was selected as the research object， and the spatiotemporal variation of pH value in rhizosphere microdomain under the heavy metal stress of chromium and nickel， and the influence on enzyme activity in the rhizosphere soil of L. hexandra were studied by using the planar optode technique and in-situ enzyme spectrometry. The results showed that： 1） under the stress of heavy metals chromium and nickel， the rhizosphere pH value of L. hexandra will be significantly reduced. The pH value of the soil around the rhizosphere in the CK group fluctuated between 6.57 and 7.13， but decreased sharply under the compound stress， and the pH value fluctuated between 6.00 and 6.57. Rhizosphere acidification is an important mechanism for the activation and absorption of heavy metals by hyperaccumulator plants， which may also be an important mechanism for the hyperaccumulation of chromium and nickel in L. hexandra. 2） The rhizosphere zone of L. hexandra was the hotspot of enzyme activity. Under the stress of chromium and nickel， the activity of β-glucosidase increased， and the activity of acid phosphatase decreased. The enzyme activity in the CK group fluctuated between 400 pmol/（cm2·h） and 600 pmol/（cm2·h）， while the enzyme activity in rhizosphere soil decreased to 200 to 400 pmol/（cm2·h） under heavy metal stress. These results indicated that the rhizosphere region of L. hexandra had a significant effect on enzyme activity under the stress of chromium and nickel， which may be related to the physiological mechanism of the rhizosphere of L. hexandra under stress.
2026, 44(2): 209-216.
doi: 10.13205/j.hjgc.202602023
Abstract:
In order to solve the problems of complexity and cumbersomeness in the optimization process of heavy metal pollution remediation technologies for agricultural land in mining areas， this study identified the optimization indexes of such technologies， and established a comprehensive optimization index system. Based on the improved analytic hierarchy process （AHP）， entropy weight method （EWM）， game theory， and technique for order preference by similarity to ideal solution （TOPSIS）， an optimization model for heavy metal pollution remediation of mining area agricultural land was constructed. Taking the agricultural land around a smelting slag field in Gejiu City， Yunnan Province as an example， the constructed model was verified. The results showed that the scientificity and accuracy of the optimization indexes were improved by weight distribution optimization through the game theory model. According to the different relative closeness values of the candidate technologies， the priority ranking was determined as follows： phytoremediation was superior to soil leaching remediation， followed by animal-mediated remediation， and microbial remediation was the least effective. This indicated that in the heavy metal pollution remediation of agricultural land around the smelting slag field in Gejiu City， Yunnan Province， phytoremediation achieved the best treatment effect， which was consistent with engineering practice. Compared with the traditional models， the new model overcomes the shortcomings of ambiguous indicators， subjective weighting， and single evaluation method inherent in traditional evaluation systems， and has certain practical application value， which can provide a reference for heavy metal pollution remediation projects of agricultural land in mining areas.
In order to solve the problems of complexity and cumbersomeness in the optimization process of heavy metal pollution remediation technologies for agricultural land in mining areas， this study identified the optimization indexes of such technologies， and established a comprehensive optimization index system. Based on the improved analytic hierarchy process （AHP）， entropy weight method （EWM）， game theory， and technique for order preference by similarity to ideal solution （TOPSIS）， an optimization model for heavy metal pollution remediation of mining area agricultural land was constructed. Taking the agricultural land around a smelting slag field in Gejiu City， Yunnan Province as an example， the constructed model was verified. The results showed that the scientificity and accuracy of the optimization indexes were improved by weight distribution optimization through the game theory model. According to the different relative closeness values of the candidate technologies， the priority ranking was determined as follows： phytoremediation was superior to soil leaching remediation， followed by animal-mediated remediation， and microbial remediation was the least effective. This indicated that in the heavy metal pollution remediation of agricultural land around the smelting slag field in Gejiu City， Yunnan Province， phytoremediation achieved the best treatment effect， which was consistent with engineering practice. Compared with the traditional models， the new model overcomes the shortcomings of ambiguous indicators， subjective weighting， and single evaluation method inherent in traditional evaluation systems， and has certain practical application value， which can provide a reference for heavy metal pollution remediation projects of agricultural land in mining areas.
