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2025 Vol. 43, No. 5
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2025, 43(5): 1-10.
doi: 10.13205/j.hjgc.202505001
Abstract:
Low-temperature wastewater falls outside the optimal temperature range for nitrifying and denitrifying bacteria， presenting a challenge for wastewater treatment plants （WWTPs） to meet effluent standards in winter. To address this issue， cold-tolerant nitrifying sludge was enriched. Changes in the abundance of community composition and functional genes during the enrichment were observed. The relationship between biological communities and functional genes was investigated to reveal the physiological functions and nitrogen metabolism mechanisms of biological communities. A sequencing batch reactor （SBR） was established to enrich cold-tolerant nitrifying sludge， with an initial NH4+-N concentration of 50 mg/L at a temperature of 30 °C. The NH4+-N concentration was subsequently increased to 200 mg/L in a gradient of 50 mg/L. Following this phase， the sludge was transferred to a low-temperature incubator maintained at 10°C. NH4+-N concentration in the effluent remained below 5 mg/L after 100 days， indicating that cold-tolerant nitrifying sludge had been successfully enriched. High-throughput sequencing results indicated that high concentrations of NH4+-N reduced microbial richness and diversity， while low temperature mainly reduced microbial diversity. Bacterial communities related to nitrogen cycling， such as Methylophilaceae， Comamondaceae， and Saprospiraceae， remained unchanged. The abundance of functional genes（nifD and nifK） related to nitrogen fixation decreased， while the abundance of nitrate （NO3--N） assimilatory reduction gene nasA and nitrite （NO2--N） reduction gene（nirB and nirD） increased. Meanwhile， the enrichment process also enhanced carbohydrate metabolism and fatty acid metabolism， strengthening the energy supply by increasing adenosine triphosphate （ATP） hydrolysis to resist adverse conditions. In addition， an increased abundance of key enzymes ［EC：3.5.5.1］， ［EC：1.7.99.4］ and ［EC：17.2.4］ was related to nitrogen cycling， confirming the promotion of nitrification and denitrification by enrichment. The above research provides theoretical support for nitrogen removal in sewage treatment under low temperatures.
Low-temperature wastewater falls outside the optimal temperature range for nitrifying and denitrifying bacteria， presenting a challenge for wastewater treatment plants （WWTPs） to meet effluent standards in winter. To address this issue， cold-tolerant nitrifying sludge was enriched. Changes in the abundance of community composition and functional genes during the enrichment were observed. The relationship between biological communities and functional genes was investigated to reveal the physiological functions and nitrogen metabolism mechanisms of biological communities. A sequencing batch reactor （SBR） was established to enrich cold-tolerant nitrifying sludge， with an initial NH4+-N concentration of 50 mg/L at a temperature of 30 °C. The NH4+-N concentration was subsequently increased to 200 mg/L in a gradient of 50 mg/L. Following this phase， the sludge was transferred to a low-temperature incubator maintained at 10°C. NH4+-N concentration in the effluent remained below 5 mg/L after 100 days， indicating that cold-tolerant nitrifying sludge had been successfully enriched. High-throughput sequencing results indicated that high concentrations of NH4+-N reduced microbial richness and diversity， while low temperature mainly reduced microbial diversity. Bacterial communities related to nitrogen cycling， such as Methylophilaceae， Comamondaceae， and Saprospiraceae， remained unchanged. The abundance of functional genes（nifD and nifK） related to nitrogen fixation decreased， while the abundance of nitrate （NO3--N） assimilatory reduction gene nasA and nitrite （NO2--N） reduction gene（nirB and nirD） increased. Meanwhile， the enrichment process also enhanced carbohydrate metabolism and fatty acid metabolism， strengthening the energy supply by increasing adenosine triphosphate （ATP） hydrolysis to resist adverse conditions. In addition， an increased abundance of key enzymes ［EC：3.5.5.1］， ［EC：1.7.99.4］ and ［EC：17.2.4］ was related to nitrogen cycling， confirming the promotion of nitrification and denitrification by enrichment. The above research provides theoretical support for nitrogen removal in sewage treatment under low temperatures.
Adsorption performance and mechanism of activated coke on polymorphic phosphorus pollutants in water
2025, 43(5): 11-19.
doi: 10.13205/j.hjgc.202505002
Abstract:
In order to achieve efficient removal of polymorphic phosphorus pollutants in wastewater， this study took activated coke， a carbon-based adsorbent which is cheap， easy to obtain， and has high mechanical strength and rich active sites， as the research object. Corresponding adsorption efficiency and mechanism for polymorphic phosphorus pollutants was evaluated through static adsorption experiments. The characterization of the microscopic morphology and surface characteristics of activated coke showed that the layered structure composed of carbon atoms is disorderly arranged and stacked. The specific surface area of activated coke was 675 m2/g and the internal pore structure was mainly micropores. Dimethoate （>90%） and trichlorfon （>70%） could be efficiently removed by adsorption while the removal efficiency of phosphite （<20%） and hypophosphite （<10%） was low. The results of the kinetic analysis showed that the adsorption of phosphorus pollutants by activated coke mainly followed the quasi-second-order kinetic model （R2>0.98）. In terms of adsorption isotherm， the adsorption process of activated coke on organic phosphorus pollutants was mostly single-layer adsorption. In contrast， the adsorption of inorganic phosphorus pollutants was multi-layer adsorption. The adsorption mechanism of activated coke was evaluated using glyphosate as a model pollutant， and it was confirmed that the adsorption process was dominated by chemical effects. The adsorption efficiency will be affected by solution pH， which decreased from 48% to 8% while increasing pH from 2.00 to 4.00. The above research provides a reference for the application of activated coke in the efficient treatment of phosphorus-containing wastewater.
In order to achieve efficient removal of polymorphic phosphorus pollutants in wastewater， this study took activated coke， a carbon-based adsorbent which is cheap， easy to obtain， and has high mechanical strength and rich active sites， as the research object. Corresponding adsorption efficiency and mechanism for polymorphic phosphorus pollutants was evaluated through static adsorption experiments. The characterization of the microscopic morphology and surface characteristics of activated coke showed that the layered structure composed of carbon atoms is disorderly arranged and stacked. The specific surface area of activated coke was 675 m2/g and the internal pore structure was mainly micropores. Dimethoate （>90%） and trichlorfon （>70%） could be efficiently removed by adsorption while the removal efficiency of phosphite （<20%） and hypophosphite （<10%） was low. The results of the kinetic analysis showed that the adsorption of phosphorus pollutants by activated coke mainly followed the quasi-second-order kinetic model （R2>0.98）. In terms of adsorption isotherm， the adsorption process of activated coke on organic phosphorus pollutants was mostly single-layer adsorption. In contrast， the adsorption of inorganic phosphorus pollutants was multi-layer adsorption. The adsorption mechanism of activated coke was evaluated using glyphosate as a model pollutant， and it was confirmed that the adsorption process was dominated by chemical effects. The adsorption efficiency will be affected by solution pH， which decreased from 48% to 8% while increasing pH from 2.00 to 4.00. The above research provides a reference for the application of activated coke in the efficient treatment of phosphorus-containing wastewater.
2025, 43(5): 20-27.
doi: 10.13205/j.hjgc.202505003
Abstract:
Steel industrial parks consume large amount of water， including both industrial and domestic water. Domestic wastewater in steel enterprises typically originates from canteens， bathrooms， and toilets， and contains pollutants like COD， BOD， and NH3-N. Biological filters， known for their high efficiency and simplicity of operation， are commonly used for treating such wastewater. However， these wastewater streams often exhibit low carbon-to-nitrogen （C/N） ratios， posing challenges for biological nitrogen removal. In addition to domestic wastewater， steel industrial parks generate various production wastewater streams， such as coking wastewater， rolling wastewater， and gas condensate. With the increasing emphasis on achieving zero discharge of industrial wastewater， treating these streams separately has become essential. Gas condensate， which is similar in composition to domestic wastewater， contains biodegradable organics. Integrating its treatment with domestic wastewater can address the low C/N issue while reducing treatment costs. However， no existing studies have explored the feasibility of co-treating gas condensate and domestic wastewater.This study investigated the feasibility and effectiveness of integrating gas condensate with domestic wastewater treatment through a pilot-scale experiment in a steel industrial park. We monitored water quality changes and evaluated the impact of introducing gas condensate on microbial community diversity and structure using high-throughput sequencing. Correlation analyses between water quality parameters and microbial community characteristics were conducted to elucidate the mechanisms underlying treatment efficiency improvements. The study demonstrated that the integration of gas condensate significantly increased the concentration of organic matters in the influent， as evidenced by a 100% increase in BOD， and a 39% increase in COD. Despite this， the effluent COD levels remained stable and complied with the Discharge Standard of Water Pollutants for Iron and Steel Industry （GB 13456—2012）. The removal efficiency of COD improved from 51.8% to 66.8%， indicating enhanced system performance under higher organic loading. In terms of nitrogen removal， the addition of gas condensate did not adversely affect ammonia removal but significantly improved the total nitrogen removal efficiency from 10.5% to 15.0%. This was attributed to increased organic carbon availability for denitrification and potential shifts in microbial community dynamics. Microbial diversity analysis showed significant fluctuations in the Shannon， Pielou-e， Simpson， and Chao1 indices， indicating that gas condensate altered microbial community composition and metabolic pathways. The introduction of gas condensate also altered microbial community diversity， particularly enriching the genus Dechloromonas， which was significantly correlated with carbon and nitrogen removal. This practical case offers theoretical and technical guidance for low-carbon wastewater treatment and reuse in the steel industry.
Steel industrial parks consume large amount of water， including both industrial and domestic water. Domestic wastewater in steel enterprises typically originates from canteens， bathrooms， and toilets， and contains pollutants like COD， BOD， and NH3-N. Biological filters， known for their high efficiency and simplicity of operation， are commonly used for treating such wastewater. However， these wastewater streams often exhibit low carbon-to-nitrogen （C/N） ratios， posing challenges for biological nitrogen removal. In addition to domestic wastewater， steel industrial parks generate various production wastewater streams， such as coking wastewater， rolling wastewater， and gas condensate. With the increasing emphasis on achieving zero discharge of industrial wastewater， treating these streams separately has become essential. Gas condensate， which is similar in composition to domestic wastewater， contains biodegradable organics. Integrating its treatment with domestic wastewater can address the low C/N issue while reducing treatment costs. However， no existing studies have explored the feasibility of co-treating gas condensate and domestic wastewater.This study investigated the feasibility and effectiveness of integrating gas condensate with domestic wastewater treatment through a pilot-scale experiment in a steel industrial park. We monitored water quality changes and evaluated the impact of introducing gas condensate on microbial community diversity and structure using high-throughput sequencing. Correlation analyses between water quality parameters and microbial community characteristics were conducted to elucidate the mechanisms underlying treatment efficiency improvements. The study demonstrated that the integration of gas condensate significantly increased the concentration of organic matters in the influent， as evidenced by a 100% increase in BOD， and a 39% increase in COD. Despite this， the effluent COD levels remained stable and complied with the Discharge Standard of Water Pollutants for Iron and Steel Industry （GB 13456—2012）. The removal efficiency of COD improved from 51.8% to 66.8%， indicating enhanced system performance under higher organic loading. In terms of nitrogen removal， the addition of gas condensate did not adversely affect ammonia removal but significantly improved the total nitrogen removal efficiency from 10.5% to 15.0%. This was attributed to increased organic carbon availability for denitrification and potential shifts in microbial community dynamics. Microbial diversity analysis showed significant fluctuations in the Shannon， Pielou-e， Simpson， and Chao1 indices， indicating that gas condensate altered microbial community composition and metabolic pathways. The introduction of gas condensate also altered microbial community diversity， particularly enriching the genus Dechloromonas， which was significantly correlated with carbon and nitrogen removal. This practical case offers theoretical and technical guidance for low-carbon wastewater treatment and reuse in the steel industry.
2025, 43(5): 28-37.
doi: 10.13205/j.hjgc.202505004
Abstract:
The high concentration of phosphorus in farmland runoff along a river in Shenzhen leads to the risk of excessive phosphorus in the river section. Considering the characteristics of local rainy and dry seasons as well as short-term rainfall drainage， a metal-modified biochar-based phosphorus adsorption removal technology was proposed to control phosphorus in farmland rainfall-runoff. In this paper， the local abundant landscape plant deciduous biomass was used as the raw material， and the non-toxic metals Ca， Fe and Mg were used to modify it. The optimal pyrolysis temperatures were determined to be 500， 400 and 600 °C， and three metal-modified biochars （CaBC500， FeBC400， MgBC600） were prepared respectively. The metal-modified biochar was used as a filler to adsorb phosphorus in a fixed-bed reactor to treat the actual farmland runoff. The results showed that MgBC600 had the highest dynamic phosphorus adsorption capacity of 61.20 mg/g. The MgBC600/CaBC500 two-stage series fixed-bed reactor demonstrated better phosphorus removal efficiency in the early stage of adsorption. In addition， the metal-modified biochar was also mixed with soil to achieve the in situ phosphorus fixation. The results indicated an optimal doping ratio of 1%. The phosphorus fixation effects of FeBC400 and MgBC600 were relatively stable， and the fixation rate of phosphorus in the early precipitation was above 70% and 75%， respectively. The average concentrations of calcium ions， iron ions， and magnesium ions in the actual stormwater runoff were 1.771，0.159，1.773 mg/L， respectively， the concentrations of calcium ions and magnesium ions in the effluent water from the fixed bed increased slightly but remained below 5 mg/L， while the concentration of iron ions was consistently below 0.02 mg/L. The results demonstrated that the use of fixed beds with metal-modified biochar packing to control phosphorus in stormwater runoff achieved a low average concentration of dissolved metal ions and did not cause secondary pollution. At a doping ratio of 1%， the metal dissolution concentrations of the metal-modified biochar CaBC500， FeBC400， and MgBC600 were 3.553，0.003，4.013 mg/L， respectively， which didn't not cause secondary pollution.
The high concentration of phosphorus in farmland runoff along a river in Shenzhen leads to the risk of excessive phosphorus in the river section. Considering the characteristics of local rainy and dry seasons as well as short-term rainfall drainage， a metal-modified biochar-based phosphorus adsorption removal technology was proposed to control phosphorus in farmland rainfall-runoff. In this paper， the local abundant landscape plant deciduous biomass was used as the raw material， and the non-toxic metals Ca， Fe and Mg were used to modify it. The optimal pyrolysis temperatures were determined to be 500， 400 and 600 °C， and three metal-modified biochars （CaBC500， FeBC400， MgBC600） were prepared respectively. The metal-modified biochar was used as a filler to adsorb phosphorus in a fixed-bed reactor to treat the actual farmland runoff. The results showed that MgBC600 had the highest dynamic phosphorus adsorption capacity of 61.20 mg/g. The MgBC600/CaBC500 two-stage series fixed-bed reactor demonstrated better phosphorus removal efficiency in the early stage of adsorption. In addition， the metal-modified biochar was also mixed with soil to achieve the in situ phosphorus fixation. The results indicated an optimal doping ratio of 1%. The phosphorus fixation effects of FeBC400 and MgBC600 were relatively stable， and the fixation rate of phosphorus in the early precipitation was above 70% and 75%， respectively. The average concentrations of calcium ions， iron ions， and magnesium ions in the actual stormwater runoff were 1.771，0.159，1.773 mg/L， respectively， the concentrations of calcium ions and magnesium ions in the effluent water from the fixed bed increased slightly but remained below 5 mg/L， while the concentration of iron ions was consistently below 0.02 mg/L. The results demonstrated that the use of fixed beds with metal-modified biochar packing to control phosphorus in stormwater runoff achieved a low average concentration of dissolved metal ions and did not cause secondary pollution. At a doping ratio of 1%， the metal dissolution concentrations of the metal-modified biochar CaBC500， FeBC400， and MgBC600 were 3.553，0.003，4.013 mg/L， respectively， which didn't not cause secondary pollution.
2025, 43(5): 38-45.
doi: 10.13205/j.hjgc.202505005
Abstract:
In recent years， numerous industrial activities have discharged substantial amounts of saline wastewater. Although many halotolerant bacteria have been selected from natural environments， the complexity and interconnectivity of the metabolic networks that constitute biological systems make it impossible to manually clarify the hundreds to thousands of components within a target strain. With the advancement of high-throughput technologies， genome-scale metabolic network models （GEMs） have emerged as a novel model for understanding microbial biochemical phenotypes at the system level， enabling the description and prediction of strain behavior. The study constructed the first GEM of Oceanimonas. Through corrections of ATP synthesis， the respiratory chain， and biomass composition， the final model， named iZJ929， was established. Leveraging this model， the metabolic flux distribution in the central metabolic pathway of this strain was predicted。It was found that the fluxes of glycolysis and tricarboxylic acid cycle pathway increased under anaerobic conditions to meet the energy demands of the cell. The overexpression targets for ectoine production were analyzed. When glucose and acetate were used as simulated substrates， there were 8 and 7 potential amplification targets， respectively， which provided valuable information for subsequent genetic modifications. Overall， GEMs serve as effective tools in the field of environmental engineering， and the establishment of this model provides theoretical support for analyzing the growth phenotype of Oceanimonas sp. GK1.
In recent years， numerous industrial activities have discharged substantial amounts of saline wastewater. Although many halotolerant bacteria have been selected from natural environments， the complexity and interconnectivity of the metabolic networks that constitute biological systems make it impossible to manually clarify the hundreds to thousands of components within a target strain. With the advancement of high-throughput technologies， genome-scale metabolic network models （GEMs） have emerged as a novel model for understanding microbial biochemical phenotypes at the system level， enabling the description and prediction of strain behavior. The study constructed the first GEM of Oceanimonas. Through corrections of ATP synthesis， the respiratory chain， and biomass composition， the final model， named iZJ929， was established. Leveraging this model， the metabolic flux distribution in the central metabolic pathway of this strain was predicted。It was found that the fluxes of glycolysis and tricarboxylic acid cycle pathway increased under anaerobic conditions to meet the energy demands of the cell. The overexpression targets for ectoine production were analyzed. When glucose and acetate were used as simulated substrates， there were 8 and 7 potential amplification targets， respectively， which provided valuable information for subsequent genetic modifications. Overall， GEMs serve as effective tools in the field of environmental engineering， and the establishment of this model provides theoretical support for analyzing the growth phenotype of Oceanimonas sp. GK1.
2025, 43(5): 46-56.
doi: 10.13205/j.hjgc.202505006
Abstract:
Electro-adsorption technology is often used to remove low concentrations of chloride ions from reclaimed water. However， unmodified activated carbon fibers （ACF） electrodes exhibite a low chloride ion （Cl-） removal rate due to their weak electro-adsorption capacity. In this study， modified ACF electrodes were prepared using two specific methods， namely the sol-gel method （with TiO2） and the in-situ polymerization method （with PANI），to enhance the performance of the ACF electrodes. Subsequently， a comprehensive investigation was carried out to study the electro-adsorption performance of these modified ACF electrodes in removing Cl- from simulated reclaimed water. Moreover， the regeneration performance of these electrodes was also explored under diverse conditions. This dual focus on both electro-adsorption and regeneration aimed to evaluate the overall feasibility and practicality of using these modified electrodes in actual reclaimed water treatment scenarios.The experimental results were quite remarkable. It was found that under specific conditions， which included the use of 5 pairs of electrode plates， a plate spacing of 2 mm， an applied voltage of 2 V， and an initial Cl- concentration of 120 mg/L， the removal rate of Cl- by the modified electrode in simulated reclaimed water reached an impressive 96.25%. Even in actual reclaimed water， the removal rate was as high as 80.42%. These figures clearly demonstrated the enhanced efficacy of the modified electrodes compared to their unmodified counterparts. Furthermore， based on X-ray diffraction （XRD）， scanning electron microscopy （SEM）， and Fourier transform infrared spectroscopy （FTIR）， an in-depth discussion was conducted on Cl- removal mechanism by the PANI@TiO2/ACF electrode. It was proved that the co-modification of TiO2 and PANI on the ACF electrode played a vital role in enhancing various electrode properties. Specifically， it significantly enhanced both the electrical conductivity and physical adsorption capacity of the electrode. As a direct consequence of these improvements， the electro-adsorption rate and adsorption capacity of the modified electrode were observably enhanced. This showcases the potential of these modified electrodes in improving the removal of Cl- from reclaimed water， but also provides data and theoriotic reference for future industrial applications of electro-adsorption technology.
Electro-adsorption technology is often used to remove low concentrations of chloride ions from reclaimed water. However， unmodified activated carbon fibers （ACF） electrodes exhibite a low chloride ion （Cl-） removal rate due to their weak electro-adsorption capacity. In this study， modified ACF electrodes were prepared using two specific methods， namely the sol-gel method （with TiO2） and the in-situ polymerization method （with PANI），to enhance the performance of the ACF electrodes. Subsequently， a comprehensive investigation was carried out to study the electro-adsorption performance of these modified ACF electrodes in removing Cl- from simulated reclaimed water. Moreover， the regeneration performance of these electrodes was also explored under diverse conditions. This dual focus on both electro-adsorption and regeneration aimed to evaluate the overall feasibility and practicality of using these modified electrodes in actual reclaimed water treatment scenarios.The experimental results were quite remarkable. It was found that under specific conditions， which included the use of 5 pairs of electrode plates， a plate spacing of 2 mm， an applied voltage of 2 V， and an initial Cl- concentration of 120 mg/L， the removal rate of Cl- by the modified electrode in simulated reclaimed water reached an impressive 96.25%. Even in actual reclaimed water， the removal rate was as high as 80.42%. These figures clearly demonstrated the enhanced efficacy of the modified electrodes compared to their unmodified counterparts. Furthermore， based on X-ray diffraction （XRD）， scanning electron microscopy （SEM）， and Fourier transform infrared spectroscopy （FTIR）， an in-depth discussion was conducted on Cl- removal mechanism by the PANI@TiO2/ACF electrode. It was proved that the co-modification of TiO2 and PANI on the ACF electrode played a vital role in enhancing various electrode properties. Specifically， it significantly enhanced both the electrical conductivity and physical adsorption capacity of the electrode. As a direct consequence of these improvements， the electro-adsorption rate and adsorption capacity of the modified electrode were observably enhanced. This showcases the potential of these modified electrodes in improving the removal of Cl- from reclaimed water， but also provides data and theoriotic reference for future industrial applications of electro-adsorption technology.
2025, 43(5): 57-66.
doi: 10.13205/j.hjgc.202505007
Abstract:
Natural attenuation technology has been widely applied abroad in recent years thanks to its features such as cost-effectiveness and sustainability. However， in China， there is currently a lack of complete engineering application cases. This paper conducts a visual analysis on global literature published in the field of natural attenuation from 2001 to 2021 by relying on the CiteSpace software and taking the Web of Science（WOS） Core Database as the data source. The results reveal that the United States occupies a dominant position in this field. The number of papers published by the United States accounts for 31.7% of the total number of papers published worldwide. In China， the most influential institution in this field is the Chinese Academy of Sciences. Currently， the research in the field of natural attenuation can be divided into two stages. During the first stage， the main focus is on the mechanism and application of natural attenuation. In the second stage， the emphasis is mainly placed on how to enhance the natural attenuation process through biostimulation or bioaugmentation methods. In future research efforts， more attention should be directed towards the natural attenuation process that is dominated by organisms. Meanwhile， greater emphasis should also be placed on the natural attenuation process of organic pollutants. It is essential to explore deeper into these aspects as they play crucial roles in understanding and improving the application of natural attenuation technology. The natural attenuation process dominated by organisms may involve complex interactions among various biological factors， and more in-depth study of it can help us better utilize the natural power of biological systems to deal with environmental issues. Similarly， organic pollutants are common and have significant impacts on the ecological environment. Focusing on their natural attenuation processes can provide valuable insights for developing more effective pollution control and environmental restoration strategies.
Natural attenuation technology has been widely applied abroad in recent years thanks to its features such as cost-effectiveness and sustainability. However， in China， there is currently a lack of complete engineering application cases. This paper conducts a visual analysis on global literature published in the field of natural attenuation from 2001 to 2021 by relying on the CiteSpace software and taking the Web of Science（WOS） Core Database as the data source. The results reveal that the United States occupies a dominant position in this field. The number of papers published by the United States accounts for 31.7% of the total number of papers published worldwide. In China， the most influential institution in this field is the Chinese Academy of Sciences. Currently， the research in the field of natural attenuation can be divided into two stages. During the first stage， the main focus is on the mechanism and application of natural attenuation. In the second stage， the emphasis is mainly placed on how to enhance the natural attenuation process through biostimulation or bioaugmentation methods. In future research efforts， more attention should be directed towards the natural attenuation process that is dominated by organisms. Meanwhile， greater emphasis should also be placed on the natural attenuation process of organic pollutants. It is essential to explore deeper into these aspects as they play crucial roles in understanding and improving the application of natural attenuation technology. The natural attenuation process dominated by organisms may involve complex interactions among various biological factors， and more in-depth study of it can help us better utilize the natural power of biological systems to deal with environmental issues. Similarly， organic pollutants are common and have significant impacts on the ecological environment. Focusing on their natural attenuation processes can provide valuable insights for developing more effective pollution control and environmental restoration strategies.
2025, 43(5): 67-74.
doi: 10.13205/j.hjgc.202505008
Abstract:
The biological decolorization of traditional azo dyes is usually limited by low electron transfer rates， which can be addressed by the addition of nanoparticles with redox-active properties to form a stable biohybrid system. A surface-precipitated R. planticola/MoS2 biohybrid with good biocompatibility was constructed. Batch experiments showed that biohybrids incorporating 0.1-0.7 mmol/L molybdic sulfide （MoS2） promoted the biological decolorization of methyl orange （MO），with R. planticola/MoS2（0.5mmol/L） exhibiting the fastest decolorization efficiency. The R. planticola/MoS2 biohybrid improved microbial metabolic activity and electron transfer capacity， as evidenced by a respective increase of 92.08%， 42.61%， 85.89%， and 37.58% in the levels of nicotinamide adenine dinucleotide （NADH）， adenosine triphosphate （ATP）， and electron transfer system activity （ETSA）. In addition， the R. planticola/MoS2 biohybrid increased the content of extracellular polymeric substances（EPS） and promoted the expression of redox-active substances and functional groups. This study provided a novel strategy for accelerating the biodegradation of azo dyes and deepened the understanding of the interactions between nanomaterials and microorganisms.
The biological decolorization of traditional azo dyes is usually limited by low electron transfer rates， which can be addressed by the addition of nanoparticles with redox-active properties to form a stable biohybrid system. A surface-precipitated R. planticola/MoS2 biohybrid with good biocompatibility was constructed. Batch experiments showed that biohybrids incorporating 0.1-0.7 mmol/L molybdic sulfide （MoS2） promoted the biological decolorization of methyl orange （MO），with R. planticola/MoS2（0.5mmol/L） exhibiting the fastest decolorization efficiency. The R. planticola/MoS2 biohybrid improved microbial metabolic activity and electron transfer capacity， as evidenced by a respective increase of 92.08%， 42.61%， 85.89%， and 37.58% in the levels of nicotinamide adenine dinucleotide （NADH）， adenosine triphosphate （ATP）， and electron transfer system activity （ETSA）. In addition， the R. planticola/MoS2 biohybrid increased the content of extracellular polymeric substances（EPS） and promoted the expression of redox-active substances and functional groups. This study provided a novel strategy for accelerating the biodegradation of azo dyes and deepened the understanding of the interactions between nanomaterials and microorganisms.
2025, 43(5): 75-83.
doi: 10.13205/j.hjgc.202505009
Abstract:
At present， some local and national government-level technical guidelines on vapor intrusion risk assessment have been promulgated globally， but the establishment of these guidelines all take soil vapor intrusion as the main transmission path of pollutants， and only a few scholars have carried out discussions on the distribution characteristics of gaseous volatile organic compounds （VOCs） pollutants in underground pipeline networks and their migration rules to neighboring buildings. Long-term and multi-frequency gas sample collection were conducted on 2 municipal pipeline networks to investigate the constitution and distribution of VOCs. Quantitatively and qualitatively analytical measurements were performed on gas samples. The vapor intrusion risks of these VOCs were assessed using an attenuation factor approach. The results suggested that VOCs were commonly present in the gases of the two investigated municipal pipeline networks. At Site A， the main pollutants in the pipeline network were dichloromethane and tetrachloroethylene， while at Site B， the main pollutants were trichloromethane， carbon tetrachloride， 1，2-dichloropropane， and tetrachloroethylene. Both sites exhibited strong spatial and temporal fluctuations of VOCs. The variation coefficient of the main VOCs ranged from 26.75% to 178.38% at Site A， and from 134.15% to 202.89% at Site B. The results of the vapor intrusion risk assessment indicated that the attenuation factor for vapor intrusion from the sewer pipeline to indoor air ranged from 0.0028 to 0.30 at Site A. In addition，VOCs in approximately 30% of the pipeline segments had the potential to cause indoor pollutants concentrations to exceed the standards at Site B.
At present， some local and national government-level technical guidelines on vapor intrusion risk assessment have been promulgated globally， but the establishment of these guidelines all take soil vapor intrusion as the main transmission path of pollutants， and only a few scholars have carried out discussions on the distribution characteristics of gaseous volatile organic compounds （VOCs） pollutants in underground pipeline networks and their migration rules to neighboring buildings. Long-term and multi-frequency gas sample collection were conducted on 2 municipal pipeline networks to investigate the constitution and distribution of VOCs. Quantitatively and qualitatively analytical measurements were performed on gas samples. The vapor intrusion risks of these VOCs were assessed using an attenuation factor approach. The results suggested that VOCs were commonly present in the gases of the two investigated municipal pipeline networks. At Site A， the main pollutants in the pipeline network were dichloromethane and tetrachloroethylene， while at Site B， the main pollutants were trichloromethane， carbon tetrachloride， 1，2-dichloropropane， and tetrachloroethylene. Both sites exhibited strong spatial and temporal fluctuations of VOCs. The variation coefficient of the main VOCs ranged from 26.75% to 178.38% at Site A， and from 134.15% to 202.89% at Site B. The results of the vapor intrusion risk assessment indicated that the attenuation factor for vapor intrusion from the sewer pipeline to indoor air ranged from 0.0028 to 0.30 at Site A. In addition，VOCs in approximately 30% of the pipeline segments had the potential to cause indoor pollutants concentrations to exceed the standards at Site B.
2025, 43(5): 84-94.
doi: 10.13205/j.hjgc.202505010
Abstract:
Volatile organic compounds （VOCs） are a significant class of pollutants in the atmosphere. Biological technology is widely used in treating VOCs with large air flow rates and low concentrations， because of the advantages of mild reaction conditions， low economic cost， and minimal secondary pollution. Proper reactor modeling can effectively simulate reactor operation， chemical reactions， and substance transport processes. The early models were mainly used to simulate the biofilm dynamics of gas flow， phase transfer， biodegradation， and biological growth. The methods used to establish the models were relatively standard， generally accepted， and widely used in industry. In recent years， with the development of fluid mechanics， mathematics， and computer science， new models can simulate more complex processes while ensuring the repeatability and stability. In this paper， the research progress of bioreactor models for VOCs was reviewed， focusing on the classical biofilm dynamics model， the computational fluid dynamics（CFD） model for bioreactors， and the artificial neural network（ANN） model. The basic principles， important parameters， application conditions and research status of various models were expounded. The shortcomings and future development trends of bioreactor models were also analyzed， providing a scientific basis for revealing the VOC biodegradation process and improving the design and practical application of biological treatment systems. In the future， more attention should be paid to improving the combination of artificial neural network model and the CFD model to improve its operability and universality.
Volatile organic compounds （VOCs） are a significant class of pollutants in the atmosphere. Biological technology is widely used in treating VOCs with large air flow rates and low concentrations， because of the advantages of mild reaction conditions， low economic cost， and minimal secondary pollution. Proper reactor modeling can effectively simulate reactor operation， chemical reactions， and substance transport processes. The early models were mainly used to simulate the biofilm dynamics of gas flow， phase transfer， biodegradation， and biological growth. The methods used to establish the models were relatively standard， generally accepted， and widely used in industry. In recent years， with the development of fluid mechanics， mathematics， and computer science， new models can simulate more complex processes while ensuring the repeatability and stability. In this paper， the research progress of bioreactor models for VOCs was reviewed， focusing on the classical biofilm dynamics model， the computational fluid dynamics（CFD） model for bioreactors， and the artificial neural network（ANN） model. The basic principles， important parameters， application conditions and research status of various models were expounded. The shortcomings and future development trends of bioreactor models were also analyzed， providing a scientific basis for revealing the VOC biodegradation process and improving the design and practical application of biological treatment systems. In the future， more attention should be paid to improving the combination of artificial neural network model and the CFD model to improve its operability and universality.
2025, 43(5): 95-106.
doi: 10.13205/j.hjgc.202505011
Abstract:
The filter cartridge is a filter unit made by repeatedly folding the filter material into folds. Compared with traditional round bags and folded filter bags with the same size， it offers a larger filtration area while occupying less space， and has the advantages such as simple maintenance and management， low resistance， and high efficiency， etc. These features make it widely applied in the dust-containing gas filtration system where air serves as the medium. In the purification of dust-containing gas discharged from industrial kilns， most dust collectors are used in high-temperature environments， and the filter cartridge is susceptible to the influence of the depth and spacing of the fold， resulting in problems such as compaction， bagging， and dust accumulation. These problems reduce the effective filteration area of the filter cartridges， and increase the operating resistance of the system. In addition， they accelerate wear and corrosion of the filter material caused by dust， ultimately shortening the service life of the filter cartridge.The standard lengths of conventional filter cartridges typically encompass 660 mm and 1000 mm. While elongating the length of the filter cartridge enhances the filtration area and subsequently diminishes the filtration wind velocity， it might also compromise the compressed air volume or pressure， thereby impeding the sprayed airflow's capacity to penetrate the cartridge's depths for effective dust removal. To address these concerns， the present study focused on a 3 m filter cartridge， constructing a three-dimensional model of the same and employing numerical simulation analysis techniques to meticulously investigate the spraying and cleaning mechanisms of the cartridge. Upon validating the precision and credibility of these numerical simulation methods， a Venturi-style guide pipe was devised to optimize the cleaning performance of the filter cartridge. The L16（45） orthogonal test was carried out to determine the optimal range of blowing parameters for 3 m cartridges. The results showed that the radial pressure decay phenomenon occurred when the 3 m cartridge was 1.5 m away from the mouth of the bag， and the pressure distribution between the peak and trough in the middle and lower sections of the cartridge was non-uniform. The induced gas flow rate of the cartridge after the addition of a Venturi deflector was 1.47 times of that of the cartridge without a Venturi deflector， and the peak wall pressure and maximum reverse acceleration rose by 0.1 to 0.5 times， demonstrating that the addition of a Venturi deflector improved the peak wall pressure by increasing the induced gas flow rate. The results of the orthogonal tests showed that the peak wall pressure of the cartridge increased with the increase of blowing pressure and nozzle diameter but decreased with the increase of cartridge length； the optimal blowing time was 100 ms； there was an optimal blowing distance in the process of blowing， i.e.， it was 10 times the nozzle diameter. It is suggested that the blowing pressure should be 0.5 MPa without a Venturi deflector， while with a Venturi deflector， the blowing pressure should be 0.3 MPa to 0.4 MPa， the nozzle diameter should be 22 mm， and the blowing distance should be 220 mm.The research results can serve as a guideline for the design of cartridge blowing parameters and application.
The filter cartridge is a filter unit made by repeatedly folding the filter material into folds. Compared with traditional round bags and folded filter bags with the same size， it offers a larger filtration area while occupying less space， and has the advantages such as simple maintenance and management， low resistance， and high efficiency， etc. These features make it widely applied in the dust-containing gas filtration system where air serves as the medium. In the purification of dust-containing gas discharged from industrial kilns， most dust collectors are used in high-temperature environments， and the filter cartridge is susceptible to the influence of the depth and spacing of the fold， resulting in problems such as compaction， bagging， and dust accumulation. These problems reduce the effective filteration area of the filter cartridges， and increase the operating resistance of the system. In addition， they accelerate wear and corrosion of the filter material caused by dust， ultimately shortening the service life of the filter cartridge.The standard lengths of conventional filter cartridges typically encompass 660 mm and 1000 mm. While elongating the length of the filter cartridge enhances the filtration area and subsequently diminishes the filtration wind velocity， it might also compromise the compressed air volume or pressure， thereby impeding the sprayed airflow's capacity to penetrate the cartridge's depths for effective dust removal. To address these concerns， the present study focused on a 3 m filter cartridge， constructing a three-dimensional model of the same and employing numerical simulation analysis techniques to meticulously investigate the spraying and cleaning mechanisms of the cartridge. Upon validating the precision and credibility of these numerical simulation methods， a Venturi-style guide pipe was devised to optimize the cleaning performance of the filter cartridge. The L16（45） orthogonal test was carried out to determine the optimal range of blowing parameters for 3 m cartridges. The results showed that the radial pressure decay phenomenon occurred when the 3 m cartridge was 1.5 m away from the mouth of the bag， and the pressure distribution between the peak and trough in the middle and lower sections of the cartridge was non-uniform. The induced gas flow rate of the cartridge after the addition of a Venturi deflector was 1.47 times of that of the cartridge without a Venturi deflector， and the peak wall pressure and maximum reverse acceleration rose by 0.1 to 0.5 times， demonstrating that the addition of a Venturi deflector improved the peak wall pressure by increasing the induced gas flow rate. The results of the orthogonal tests showed that the peak wall pressure of the cartridge increased with the increase of blowing pressure and nozzle diameter but decreased with the increase of cartridge length； the optimal blowing time was 100 ms； there was an optimal blowing distance in the process of blowing， i.e.， it was 10 times the nozzle diameter. It is suggested that the blowing pressure should be 0.5 MPa without a Venturi deflector， while with a Venturi deflector， the blowing pressure should be 0.3 MPa to 0.4 MPa， the nozzle diameter should be 22 mm， and the blowing distance should be 220 mm.The research results can serve as a guideline for the design of cartridge blowing parameters and application.
2025, 43(5): 107-114.
doi: 10.13205/j.hjgc.202505012
Abstract:
To alleviate the pollution caused by the foul-smelling ammonia gas produced by manure fermentation in aquaculture farms， ammonia removal strains were screened using selective culture media， and 16S rDNA gene sequence analysis and identification were carried out. Different exogenous substances such as ammonia removal bacteria， plant extracts， and physical adsorption materials with good effects were added separately. The ammonia removal effect was explored using an indoor simulation culture， and its economic benefits were evaluated to select the best exogenous additive for manure ammonia removal. The results showed that six strains with good ammonia removal effect were isolated. V1， V2， L1 and L2 were Paraburkholderia fungorum， while L3， L4 were Ralstonia insidiosa. The ammonia nitrogen removal rates were all above 60.0% within 24 hours and above 90.0% within 48 hours； among different plant extracts such as yucca extract， cinnamon extract， oak leaf extract， and lemon extract， yucca extract had the best removal effect on NH3， with an ammonia nitrogen removal rate of 12.9% within 24 hours and 14.8% within 48 hours； among different physical adsorption materials such as biochar， modified biochar， and diatomaceous earth， diatomaceous earth had the best removal effect on NH3， with an ammonia nitrogen removal rate of 26.0% within 24 hours and 22.8% within 48 hours； the costs of ammonia removal bacteria and plant extracts were low in different exogenous additives， but the cumulative NH3 removal rate of ammonia removal bacteria was 47.0 to 48.0 percentage points and 75.0 to 80.0 percentage points higher than that of plant extracts within 24 hours and 48 hours， respectively. Therefore， for the deodorization of manure in aquaculture farms， especially for reducing ammonia emissions， ammonia removal agents should be selected first， followed by plant extracts. This study provides theoretical support for selecting low-cost， efficient， and rapid exogenous additives for ammonia removal.
To alleviate the pollution caused by the foul-smelling ammonia gas produced by manure fermentation in aquaculture farms， ammonia removal strains were screened using selective culture media， and 16S rDNA gene sequence analysis and identification were carried out. Different exogenous substances such as ammonia removal bacteria， plant extracts， and physical adsorption materials with good effects were added separately. The ammonia removal effect was explored using an indoor simulation culture， and its economic benefits were evaluated to select the best exogenous additive for manure ammonia removal. The results showed that six strains with good ammonia removal effect were isolated. V1， V2， L1 and L2 were Paraburkholderia fungorum， while L3， L4 were Ralstonia insidiosa. The ammonia nitrogen removal rates were all above 60.0% within 24 hours and above 90.0% within 48 hours； among different plant extracts such as yucca extract， cinnamon extract， oak leaf extract， and lemon extract， yucca extract had the best removal effect on NH3， with an ammonia nitrogen removal rate of 12.9% within 24 hours and 14.8% within 48 hours； among different physical adsorption materials such as biochar， modified biochar， and diatomaceous earth， diatomaceous earth had the best removal effect on NH3， with an ammonia nitrogen removal rate of 26.0% within 24 hours and 22.8% within 48 hours； the costs of ammonia removal bacteria and plant extracts were low in different exogenous additives， but the cumulative NH3 removal rate of ammonia removal bacteria was 47.0 to 48.0 percentage points and 75.0 to 80.0 percentage points higher than that of plant extracts within 24 hours and 48 hours， respectively. Therefore， for the deodorization of manure in aquaculture farms， especially for reducing ammonia emissions， ammonia removal agents should be selected first， followed by plant extracts. This study provides theoretical support for selecting low-cost， efficient， and rapid exogenous additives for ammonia removal.
2025, 43(5): 115-123.
doi: 10.13205/j.hjgc.202505013
Abstract:
Sludge dewatering can effectively solve the environmental problems caused by the continuous increase of waste activated sludge. In this study， hexadecyltrimethylammonium bromide （CTAB） combined with tannic acid （TA） was innovatively applied for sludge dewatering. The results showed that the combination of CTAB （0.49 mmol/g VSS） and TA（0.16 mmol/g VSS） significantly improved the sludge dewatering performance. The sludge water content （Wc） decreased from （95.13±0.41）% to （79.18±0.33）%， and the sludge specific resistance to filtration （SRF） decreased from （28.89±0.73） × 1012 m/kg to （9.00±0.36） × 1012 m/kg. Compared with the raw sludge， the protein concentration in the tightly bound extracellular polymeric substances of the CTAB/TA treatment group decreased by 30.20 mg/L. The results of three-dimensional fluorescence spectroscopy and infrared spectroscopy indicated that CTAB/TA treatment destroyed the EPS structure and reduced its functional group count. The SEM images visually showed that a large number of drainage holes appeared on the surface of the sludge after CTAB/TA treatment. The results of this study provide a reference for sludge dewatering and resource utilization.
Sludge dewatering can effectively solve the environmental problems caused by the continuous increase of waste activated sludge. In this study， hexadecyltrimethylammonium bromide （CTAB） combined with tannic acid （TA） was innovatively applied for sludge dewatering. The results showed that the combination of CTAB （0.49 mmol/g VSS） and TA（0.16 mmol/g VSS） significantly improved the sludge dewatering performance. The sludge water content （Wc） decreased from （95.13±0.41）% to （79.18±0.33）%， and the sludge specific resistance to filtration （SRF） decreased from （28.89±0.73） × 1012 m/kg to （9.00±0.36） × 1012 m/kg. Compared with the raw sludge， the protein concentration in the tightly bound extracellular polymeric substances of the CTAB/TA treatment group decreased by 30.20 mg/L. The results of three-dimensional fluorescence spectroscopy and infrared spectroscopy indicated that CTAB/TA treatment destroyed the EPS structure and reduced its functional group count. The SEM images visually showed that a large number of drainage holes appeared on the surface of the sludge after CTAB/TA treatment. The results of this study provide a reference for sludge dewatering and resource utilization.
2025, 43(5): 124-133.
doi: 10.13205/j.hjgc.202505014
Abstract:
The high moisture content of biogas residue and the difficulty in subsequent dewatering treatment are both the bottleneck issues affecting the anaerobic digestion of food waste and the resource utilization of biogas residue. This study investigated the changing trend in dewaterability of biogas residue during the anaerobic digestion of food waste with iron-modified biochar （Fe-BC） addition， and clarified the mechanism by which iron-modified biochar improved the dewaterability. The results showed that， compared to the control group， the methane accumulation production of the Fe-BC group increased by 263.6% on the 30th day， while the normalized capillary water absorption time （NCST） decreased by 45.9%. The highest volatile suspended solids degradation rate reached 36.7% in the Fe-BC group after anaerobic digestion. The adsorption capacity of biochar alleviated ammonia inhibition， and its larger specific surface area facilitated microbial attachment and growth. As a conductive material， Fe-BC facilitated the formation of microbial aggregates associated with electron transfer， thereby establishing an electron transfer network that promoted the growth of co-metabolizing methanogens. Methane bacteria hydrolyzed large organic molecules to induce effective decomposition of EPS. Compared with the initial acidification stage of anaerobic digestion， the protein content in extracellular polymeric substances （EPS） during the stable stage decreased by 72.89%， while the carboxyl and carbonyl groups on the surface of EPS decreased by 11.2% and 13.7%， respectively. The structure of EPS was disrupted， promoting the conversion of bound water to free water. The porous structure of biochar provided a large specific surface area， offering sites for microbial attachment and growth， increasing biomass， improving protein and polysaccharide degradation， weakening the water holding capacity of EPS significantly， and enhancing dehydration performance. Moreover， the addition of Fe-BC rapidly increased the abundance of Metanoculleus， destoryed this polymer structure， convered bound water into free water， and promoted the degradation of organic compounds in EPS； during the anaerobic digestion and methanation stage， oxygen acyl reductase （OR） and acetyllactate synthetase （AS） was consumed by 33.4% and 43.6%， respectively， promoting the decomposition of volatile fatty acids （VFAs）， thereby disrupting the binding effect between organic matter and water， resulting in a decrease in bound water content and improvement of biogas residue dewaterability. This research can provide a reference for the mechanism of Fe-BC in the dehydration of food waste biogas residue.
The high moisture content of biogas residue and the difficulty in subsequent dewatering treatment are both the bottleneck issues affecting the anaerobic digestion of food waste and the resource utilization of biogas residue. This study investigated the changing trend in dewaterability of biogas residue during the anaerobic digestion of food waste with iron-modified biochar （Fe-BC） addition， and clarified the mechanism by which iron-modified biochar improved the dewaterability. The results showed that， compared to the control group， the methane accumulation production of the Fe-BC group increased by 263.6% on the 30th day， while the normalized capillary water absorption time （NCST） decreased by 45.9%. The highest volatile suspended solids degradation rate reached 36.7% in the Fe-BC group after anaerobic digestion. The adsorption capacity of biochar alleviated ammonia inhibition， and its larger specific surface area facilitated microbial attachment and growth. As a conductive material， Fe-BC facilitated the formation of microbial aggregates associated with electron transfer， thereby establishing an electron transfer network that promoted the growth of co-metabolizing methanogens. Methane bacteria hydrolyzed large organic molecules to induce effective decomposition of EPS. Compared with the initial acidification stage of anaerobic digestion， the protein content in extracellular polymeric substances （EPS） during the stable stage decreased by 72.89%， while the carboxyl and carbonyl groups on the surface of EPS decreased by 11.2% and 13.7%， respectively. The structure of EPS was disrupted， promoting the conversion of bound water to free water. The porous structure of biochar provided a large specific surface area， offering sites for microbial attachment and growth， increasing biomass， improving protein and polysaccharide degradation， weakening the water holding capacity of EPS significantly， and enhancing dehydration performance. Moreover， the addition of Fe-BC rapidly increased the abundance of Metanoculleus， destoryed this polymer structure， convered bound water into free water， and promoted the degradation of organic compounds in EPS； during the anaerobic digestion and methanation stage， oxygen acyl reductase （OR） and acetyllactate synthetase （AS） was consumed by 33.4% and 43.6%， respectively， promoting the decomposition of volatile fatty acids （VFAs）， thereby disrupting the binding effect between organic matter and water， resulting in a decrease in bound water content and improvement of biogas residue dewaterability. This research can provide a reference for the mechanism of Fe-BC in the dehydration of food waste biogas residue.
2025, 43(5): 134-142.
doi: 10.13205/j.hjgc.202505015
Abstract:
Calcium peroxide （CaO2） can effectively eliminate the black-odor of the sediment， but it can lead to the release of some heavy metals in the sediment by destabilization， resulting in potential ecological risks. To achieve the multiple effects of simultaneously eliminating the black-odor of the sediment and stabilizing heavy metals， this study develops a method for sediment remediation using hydroxyapatite and calcium peroxide （HAP/CaO2）. The results showed that the dosing HAP/CaO2 at a ratio of 3∶1 could be added to the sediment to effectively eliminate the blackness and odor of the sediment， improve the redox state and remove organic pollutants. The removal rate of acid volatile sulfide （AVS） reached about 95%， the oxidation-reduction potential （ORP） increased to 14.2 mV， and the total organic carbon （TOC） decreased by about 0.6%. Meanwhile， a variety of heavy metals were stabilized， the residual fraction of Ni， Cr， and Pb increased by about 16.9%， 26.7%， and 21.9%， respectively， and the leaching concentration decreased to below 1.0 mg/L， 1.5 mg/L， and 1.0 mg/L， respectively， complying with the stringent Technical Specification for Output Disposal of Contaminated Sediment Treatment Plant of River And Lake （SZDB/Z 236—2017） （Class I）. Moreover， there was no ecological risk in the remediated sediment， and the plant height， root length， and fresh weight of Vallisneria natans increased by 80%， 15.5%， and 18.7%， respectively， and the mortality rate of the Bellamya aeruginosa decreased by about 5%. The microbial community structure of the treated sediment did not change significantly， and Proteobacteria， Firmicutes， and Desulfobacta were always the dominant bacterium groups. This study offers an effective and safe method for treating black-odor sediment contaminated by heavy metals.
Calcium peroxide （CaO2） can effectively eliminate the black-odor of the sediment， but it can lead to the release of some heavy metals in the sediment by destabilization， resulting in potential ecological risks. To achieve the multiple effects of simultaneously eliminating the black-odor of the sediment and stabilizing heavy metals， this study develops a method for sediment remediation using hydroxyapatite and calcium peroxide （HAP/CaO2）. The results showed that the dosing HAP/CaO2 at a ratio of 3∶1 could be added to the sediment to effectively eliminate the blackness and odor of the sediment， improve the redox state and remove organic pollutants. The removal rate of acid volatile sulfide （AVS） reached about 95%， the oxidation-reduction potential （ORP） increased to 14.2 mV， and the total organic carbon （TOC） decreased by about 0.6%. Meanwhile， a variety of heavy metals were stabilized， the residual fraction of Ni， Cr， and Pb increased by about 16.9%， 26.7%， and 21.9%， respectively， and the leaching concentration decreased to below 1.0 mg/L， 1.5 mg/L， and 1.0 mg/L， respectively， complying with the stringent Technical Specification for Output Disposal of Contaminated Sediment Treatment Plant of River And Lake （SZDB/Z 236—2017） （Class I）. Moreover， there was no ecological risk in the remediated sediment， and the plant height， root length， and fresh weight of Vallisneria natans increased by 80%， 15.5%， and 18.7%， respectively， and the mortality rate of the Bellamya aeruginosa decreased by about 5%. The microbial community structure of the treated sediment did not change significantly， and Proteobacteria， Firmicutes， and Desulfobacta were always the dominant bacterium groups. This study offers an effective and safe method for treating black-odor sediment contaminated by heavy metals.
2025, 43(5): 143-152.
doi: 10.13205/j.hjgc.202505016
Abstract:
The harvesting waste of Dicranopteris Pedata in the tailing areas of ionic rare earth mines in southern China poses a huge risk of secondary pollution of rare earth elements.This study aims to explore the harmless utilization of the harvesting waste of Dicranopteris Pedata and its rare earth elements through co-pyrolysis with plastics. The rare earth hyperaccumulator Dicranopteris Pedata（DP） was co-pyrolyzed with four types of plastics （PVC， PP， PE， and PS） respectively at target temperature gradients to obtain biochar containing rare earth. The contents， speciation， bioavailability， and leaching toxicity of rare earth elements in Dicranopteris Pedata and biochar were studied， and an ecological risk assessment of rare earth elements was carried out. The results showed that pyrolysis could reduce the content of unstable forms of rare earth elements in the biomass of Dicranopteris Pedata from 60.51% to 15% below， decrease the bioavailability by more than 95%， and thus reduce the environmental risk of rare earth elements in solid residues. When the four types of plastics were added and pyrolyzed within the temperature range of 600 to 800℃， the proportions of unstable forms of rare earth elements in the biomass of Dicranopteris Pedata was reduced to within 9%， the bioavailability decreased to less than 1%， and the leaching toxicity was reduced by 80%， further reducing the environmental risk of rare earth elements. Therefore， the off-site application of rare earth biochar obtained by co-pyrolyzing plastics and Dicranopteris Pedata at a certain target temperature will not bring new environmental risks.
The harvesting waste of Dicranopteris Pedata in the tailing areas of ionic rare earth mines in southern China poses a huge risk of secondary pollution of rare earth elements.This study aims to explore the harmless utilization of the harvesting waste of Dicranopteris Pedata and its rare earth elements through co-pyrolysis with plastics. The rare earth hyperaccumulator Dicranopteris Pedata（DP） was co-pyrolyzed with four types of plastics （PVC， PP， PE， and PS） respectively at target temperature gradients to obtain biochar containing rare earth. The contents， speciation， bioavailability， and leaching toxicity of rare earth elements in Dicranopteris Pedata and biochar were studied， and an ecological risk assessment of rare earth elements was carried out. The results showed that pyrolysis could reduce the content of unstable forms of rare earth elements in the biomass of Dicranopteris Pedata from 60.51% to 15% below， decrease the bioavailability by more than 95%， and thus reduce the environmental risk of rare earth elements in solid residues. When the four types of plastics were added and pyrolyzed within the temperature range of 600 to 800℃， the proportions of unstable forms of rare earth elements in the biomass of Dicranopteris Pedata was reduced to within 9%， the bioavailability decreased to less than 1%， and the leaching toxicity was reduced by 80%， further reducing the environmental risk of rare earth elements. Therefore， the off-site application of rare earth biochar obtained by co-pyrolyzing plastics and Dicranopteris Pedata at a certain target temperature will not bring new environmental risks.
2025, 43(5): 153-159.
doi: 10.13205/j.hjgc.202505017
Abstract:
With the rapid development of urbanization in China， the huge production of garden waste in cities and towns has resulted in serious environmental pollution problems. In addition， recent treatment of garden waste is mainly focusing on incineration， which has an immediate and significant reduction effect， but is also a waste of biomass resources and unsustainable. Pyrolysis and activation are good options for resource utilization of garden waste. However， there is a lack of technical solutions to integrate pyrolysis with activation equipment to shorten the process flow and reduce the investment cost. In order to realize the scientific disposal of garden waste and improve its utilization， a pyrolysis-activation integrated furnace was developed to transform garden waste into heat and biomass-activated carbon， which verified the feasibility of the simultaneous treatment of pyrolysis and activation for garden waste. At the same time， the adsorption capacity of biomass-activated carbon on SO2 in simulated flue gas was studied. The results showed that the simultaneous treatment of pyrolysis and activation could realize the efficient disposal and resource utilization of garden waste， and realize the high-quality cogeneration of heat-carbon （activated carbon）； the biomass activated carbon after activation had an iodine value of 550 mg/g， a specific surface area of 245.94 m2/g， and a pore volume of 0.145 m3/g； the biomass activated carbon prepared from garden waste had an adsorbing capacity on SO2 of 14.4 mg/g， and that is 65% of the adsorption capacity of the commercial activated carbon. This study can provide a reference for the efficient disposal and resource utilization of garden waste， and the engineering promotion of simultaneous treatment of pyrolysis and activation.
With the rapid development of urbanization in China， the huge production of garden waste in cities and towns has resulted in serious environmental pollution problems. In addition， recent treatment of garden waste is mainly focusing on incineration， which has an immediate and significant reduction effect， but is also a waste of biomass resources and unsustainable. Pyrolysis and activation are good options for resource utilization of garden waste. However， there is a lack of technical solutions to integrate pyrolysis with activation equipment to shorten the process flow and reduce the investment cost. In order to realize the scientific disposal of garden waste and improve its utilization， a pyrolysis-activation integrated furnace was developed to transform garden waste into heat and biomass-activated carbon， which verified the feasibility of the simultaneous treatment of pyrolysis and activation for garden waste. At the same time， the adsorption capacity of biomass-activated carbon on SO2 in simulated flue gas was studied. The results showed that the simultaneous treatment of pyrolysis and activation could realize the efficient disposal and resource utilization of garden waste， and realize the high-quality cogeneration of heat-carbon （activated carbon）； the biomass activated carbon after activation had an iodine value of 550 mg/g， a specific surface area of 245.94 m2/g， and a pore volume of 0.145 m3/g； the biomass activated carbon prepared from garden waste had an adsorbing capacity on SO2 of 14.4 mg/g， and that is 65% of the adsorption capacity of the commercial activated carbon. This study can provide a reference for the efficient disposal and resource utilization of garden waste， and the engineering promotion of simultaneous treatment of pyrolysis and activation.
2025, 43(5): 160-169.
doi: 10.13205/j.hjgc.202505018
Abstract:
Bio-drying is an effective way for the rapid dehydration of food waste， but the effect of lipid degradation on the bio-drying of food waste is still unclear. Therefore， this study utilized synthetic food waste to exogenously regulate the type and content of lipid within food waste， aiming to explore the effects and mechanisms of different types and contents of lipid degradation on the dehydration efficiency of food waste during bio-drying processes. The results indicated that during the 15-day bio-drying process， from the perspective of lipid types， piles with added lard generated more heat but increased the obstruction to water mobility and inhibited extracellular enzyme activity by 22%. Piles with added soybean oil exhibited a looser physical structure， which was more conducive to water removal. Throughout the reaction， multilayer water continuously transformed into stagnant water， and starch-like substances provided the main source of bio-heat （accouting for 44.2% to 49.7%）， which was primarily used for heating water and evaporating water （43.6% to 55.5%）. From the perspective of lipid adding amount， as the lipid dosage increased， the pile's temperature rose higher， and a 6% fat addition achieved the highest dehydration efficiency of 68%. Correlation analysis revealed that the effect of lard degradation was more significant than that of soybean oil degradation and miltilayer water， indicating that it posed a stronger obstacle to water flow. At high fat contents （9% and 12%）， there was a significant negative correlation between fat and amylase activity， as well as a significant positive correlation with entrapped water， indicating that fats inhibit microbial activity and the loss of free water. In this paper， the influence of lipd on bio-drying efficiency of food waste was analyzed， which could provide theoretical support for pretreatment of food waste to regulate the de-oiling level.
Bio-drying is an effective way for the rapid dehydration of food waste， but the effect of lipid degradation on the bio-drying of food waste is still unclear. Therefore， this study utilized synthetic food waste to exogenously regulate the type and content of lipid within food waste， aiming to explore the effects and mechanisms of different types and contents of lipid degradation on the dehydration efficiency of food waste during bio-drying processes. The results indicated that during the 15-day bio-drying process， from the perspective of lipid types， piles with added lard generated more heat but increased the obstruction to water mobility and inhibited extracellular enzyme activity by 22%. Piles with added soybean oil exhibited a looser physical structure， which was more conducive to water removal. Throughout the reaction， multilayer water continuously transformed into stagnant water， and starch-like substances provided the main source of bio-heat （accouting for 44.2% to 49.7%）， which was primarily used for heating water and evaporating water （43.6% to 55.5%）. From the perspective of lipid adding amount， as the lipid dosage increased， the pile's temperature rose higher， and a 6% fat addition achieved the highest dehydration efficiency of 68%. Correlation analysis revealed that the effect of lard degradation was more significant than that of soybean oil degradation and miltilayer water， indicating that it posed a stronger obstacle to water flow. At high fat contents （9% and 12%）， there was a significant negative correlation between fat and amylase activity， as well as a significant positive correlation with entrapped water， indicating that fats inhibit microbial activity and the loss of free water. In this paper， the influence of lipd on bio-drying efficiency of food waste was analyzed， which could provide theoretical support for pretreatment of food waste to regulate the de-oiling level.
2025, 43(5): 170-177.
doi: 10.13205/j.hjgc.202505019
Abstract:
In this paper， the spent activated carbon adsorbed heavy metals from simulated industrial wastewater was utilized for CO2 gasification to produce CO-rich syngas. The effects of heavy metals， adsorption amount， reaction temperature， CO2 concentration， and flow rate on the gasification performance were investigated. The results demonstrated that both Fe3+ and Co2+ had a good promoting effect on CO2 gasification， and the activated carbon with adsorbed Co2+ had the best gasification effect， which increased the peak CO concentration by more than 130%， compared to the blank activated carbon. On the contrary， Cu2+ had a negative impact on the gasification reaction in the early stage and showed a promoting effect in the later stage. The CO2gasification activity initially increased and then decreased with the rise in heavy metal adsorption. The optimal adsorption capacity was 10%. Additionally， CO2 with a flow rate of 100 mL/min was found to be optimal， as an excessive flow would reduce the retention time of CO2 on the carbon surface. Furthermore， reaction activity exhibited a positive correlation with both reaction temperature and CO2 concentration. Combined with X-ray diffraction phase analysis （XRD）， Fourier transform infrared（FTIR） absorption spectrometry， BET-specific surface area detection method （BET）， and scanning electron microscope with energy dispersive analyzer （SEM-EDS）， we found that the heavy metal ions adsorbed on the surface of the spent activated carbon were converted into metal oxides during the reaction， thus exhibiting catalytic gasification performance. This study presents a novel approach to the resource utilization of spent activated carbon and the production of high-value syngas.
In this paper， the spent activated carbon adsorbed heavy metals from simulated industrial wastewater was utilized for CO2 gasification to produce CO-rich syngas. The effects of heavy metals， adsorption amount， reaction temperature， CO2 concentration， and flow rate on the gasification performance were investigated. The results demonstrated that both Fe3+ and Co2+ had a good promoting effect on CO2 gasification， and the activated carbon with adsorbed Co2+ had the best gasification effect， which increased the peak CO concentration by more than 130%， compared to the blank activated carbon. On the contrary， Cu2+ had a negative impact on the gasification reaction in the early stage and showed a promoting effect in the later stage. The CO2gasification activity initially increased and then decreased with the rise in heavy metal adsorption. The optimal adsorption capacity was 10%. Additionally， CO2 with a flow rate of 100 mL/min was found to be optimal， as an excessive flow would reduce the retention time of CO2 on the carbon surface. Furthermore， reaction activity exhibited a positive correlation with both reaction temperature and CO2 concentration. Combined with X-ray diffraction phase analysis （XRD）， Fourier transform infrared（FTIR） absorption spectrometry， BET-specific surface area detection method （BET）， and scanning electron microscope with energy dispersive analyzer （SEM-EDS）， we found that the heavy metal ions adsorbed on the surface of the spent activated carbon were converted into metal oxides during the reaction， thus exhibiting catalytic gasification performance. This study presents a novel approach to the resource utilization of spent activated carbon and the production of high-value syngas.
2025, 43(5): 178-191.
doi: 10.13205/j.hjgc.202505020
Abstract:
Direct air capture （DAC） technology has attracted extensive attention in recent years due to its flexible layout， simple operation， and suitability for distributed and point-type carbon emission source capture processes. In order to clarify the DAC technology's application potential in engineering， this paper systematically reviewed the principles and development route of different DAC technologies， summarized the advantages and disadvantages of liquid-based， solid-based， and emerging DAC technologies， analyzed the challenges in their development， and put forward solutions tailored to each technology. The capture materials used in various DAC technologies were briefly reviewed， and the characteristics of these materials in terms of regeneration temperature， renewable energy consumption， and capacity were compared and analyzed. The results showed that the emerging direct air capture technology reduced costs to some extent and was successfully verified in the laboratory. Before large-scale industrial application， issues such as the development of highly selective membrane materials，electrolyzer stability， and the development of efficient electrolyte systems should be solved first.
Direct air capture （DAC） technology has attracted extensive attention in recent years due to its flexible layout， simple operation， and suitability for distributed and point-type carbon emission source capture processes. In order to clarify the DAC technology's application potential in engineering， this paper systematically reviewed the principles and development route of different DAC technologies， summarized the advantages and disadvantages of liquid-based， solid-based， and emerging DAC technologies， analyzed the challenges in their development， and put forward solutions tailored to each technology. The capture materials used in various DAC technologies were briefly reviewed， and the characteristics of these materials in terms of regeneration temperature， renewable energy consumption， and capacity were compared and analyzed. The results showed that the emerging direct air capture technology reduced costs to some extent and was successfully verified in the laboratory. Before large-scale industrial application， issues such as the development of highly selective membrane materials，electrolyzer stability， and the development of efficient electrolyte systems should be solved first.
2025, 43(5): 192-198.
doi: 10.13205/j.hjgc.202505021
Abstract:
In the context of carbon peaking and carbon neutrality， the development of economical and efficient carbon capture materials has become a critical research field. Steel slag， as a solid waste， has presented considerable potential for carbon capture； however， its application is limited by relatively high external energy consumption. In order to address the shortcomings of high-temperature and high-energy-consumption of CO2 adsorption by steel slag， water was added into steel slag for a three-phase reaction at room temperature. The effects of gas flow rate， steel slag particle size， and solid-liquid ratio on CO2 adsorption efficiency in three-phase systems were studied. Then， XRD， thermodynamic， kinetic analysis， and SEM were used to analyze the adsorption product production. The results showed that the addition of a liquid phase significantly affected the adsorption efficiency of CO2 at room temperature. The diffraction peak of CaCO3 was significantly enhanced compared to that in the two-phase reaction system， indicating a higher content of generated CaCO3 crystals， better crystal form， and a higher carbonation degree. When the solid-liquid ratio was 25 g/L， the adsorption efficiency of CO2 increased obviously with the increase of the specific surface area of steel slag and the gas flow rate. At room temperature， when the gas flow rate was 250 mL/min and the steel slag particle size was 200 mesh， the adsorption efficiency was measured to be 0.97%. However， in the traditional two-phase reaction， to achieve the same efficiency，the temperature needed to be as high as 400 to 500 ℃. This study provides new ideas for the resource utilization of steel slag and low-energy-consumption CO2 capture.
In the context of carbon peaking and carbon neutrality， the development of economical and efficient carbon capture materials has become a critical research field. Steel slag， as a solid waste， has presented considerable potential for carbon capture； however， its application is limited by relatively high external energy consumption. In order to address the shortcomings of high-temperature and high-energy-consumption of CO2 adsorption by steel slag， water was added into steel slag for a three-phase reaction at room temperature. The effects of gas flow rate， steel slag particle size， and solid-liquid ratio on CO2 adsorption efficiency in three-phase systems were studied. Then， XRD， thermodynamic， kinetic analysis， and SEM were used to analyze the adsorption product production. The results showed that the addition of a liquid phase significantly affected the adsorption efficiency of CO2 at room temperature. The diffraction peak of CaCO3 was significantly enhanced compared to that in the two-phase reaction system， indicating a higher content of generated CaCO3 crystals， better crystal form， and a higher carbonation degree. When the solid-liquid ratio was 25 g/L， the adsorption efficiency of CO2 increased obviously with the increase of the specific surface area of steel slag and the gas flow rate. At room temperature， when the gas flow rate was 250 mL/min and the steel slag particle size was 200 mesh， the adsorption efficiency was measured to be 0.97%. However， in the traditional two-phase reaction， to achieve the same efficiency，the temperature needed to be as high as 400 to 500 ℃. This study provides new ideas for the resource utilization of steel slag and low-energy-consumption CO2 capture.
2025, 43(5): 199-206.
doi: 10.13205/j.hjgc.202505022
Abstract:
As a critical region for China's industrial development， accurately predicting the industrial carbon peak in Western China is essential for formulating effective emission reduction policies tailored to local characteristics. This paper proposes a carbon emission accounting system aligned with China's specific conditions to reasonably estimate industrial carbon emissions in 11 major western regions. Based on this， a combined forecasting model was established using particle swarm optimization （PSO） to optimize wavelet neural networks （WNN） for predicting the total industrial carbon emissions in the western region from 2020 to 2030. Furthermore， the final prediction results were analyzed to assess the western region's industrial carbon peak situation and reduction potential. The findings indicated that：1） under the natural peak scenario， eight administrative regions of Guangxi， Yunnan， Shaanxi， Gansu， Xinjiang， Chongqing， Qinghai， and Ningxia were expected to reach their peak before 2030， while three administrative regions of Inner Mongolia， Sichuan， and Guizhou might have some difficulties in achieving this carbon peak target. 2） in terms of carbon emission intensity reduction， the industrial sectors in the western region， except Inner Mongolia， were capable of reaching a reduction in carbon emission intensity by 60% to 65% compared to their 2005 levels. Notably， the carbon emissions in Guangxi， Chongqing， Shaanxi， Guizhou， and Yunnan were projected to decrease by more than 90%. 3） regarding emission reduction potential， the western region showed substantial overall potential， with Inner Mongolia， Qinghai， and Ningxia identified as the three regions with the highest emission reduction potential. Based on the characteristics of the industrial sectors in the western region， this paper proposed recommendations for adjusting the focus of emission reduction efforts， optimizing the energy structure， and developing dynamic peak control strategies. The primary recommendations are as follows： 1） classified regulation based on carbon emission trends across western administrative regions： administrative regions with a relatively strong foundation in carbon reduction may warrant a moderate relaxation of regulatory measures， provided that industrial carbon emissions continue to decline without rebounding. For regions that have transitioned from the growth phase to the reduction phase of carbon emissions， sustained regulation of industrial carbon reduction is essential to further decrease emissions and ensure the achievement of carbon peak targets. Conversely， regions with a weaker foundation in carbon reduction require prioritized monitoring of industrial carbon emissions. Regulatory efforts in these areas should be continuously adjusted according to their specific carbon emission levels to enhance the effectiveness of reduction measures. 2） focus on regions with high carbon reduction potential： regions with significant carbon reduction potential should be prioritized for increased policy interventions， and this can be achieved by advancing technological capabilities， promoting clean energy development， and optimizing industrial structures.
As a critical region for China's industrial development， accurately predicting the industrial carbon peak in Western China is essential for formulating effective emission reduction policies tailored to local characteristics. This paper proposes a carbon emission accounting system aligned with China's specific conditions to reasonably estimate industrial carbon emissions in 11 major western regions. Based on this， a combined forecasting model was established using particle swarm optimization （PSO） to optimize wavelet neural networks （WNN） for predicting the total industrial carbon emissions in the western region from 2020 to 2030. Furthermore， the final prediction results were analyzed to assess the western region's industrial carbon peak situation and reduction potential. The findings indicated that：1） under the natural peak scenario， eight administrative regions of Guangxi， Yunnan， Shaanxi， Gansu， Xinjiang， Chongqing， Qinghai， and Ningxia were expected to reach their peak before 2030， while three administrative regions of Inner Mongolia， Sichuan， and Guizhou might have some difficulties in achieving this carbon peak target. 2） in terms of carbon emission intensity reduction， the industrial sectors in the western region， except Inner Mongolia， were capable of reaching a reduction in carbon emission intensity by 60% to 65% compared to their 2005 levels. Notably， the carbon emissions in Guangxi， Chongqing， Shaanxi， Guizhou， and Yunnan were projected to decrease by more than 90%. 3） regarding emission reduction potential， the western region showed substantial overall potential， with Inner Mongolia， Qinghai， and Ningxia identified as the three regions with the highest emission reduction potential. Based on the characteristics of the industrial sectors in the western region， this paper proposed recommendations for adjusting the focus of emission reduction efforts， optimizing the energy structure， and developing dynamic peak control strategies. The primary recommendations are as follows： 1） classified regulation based on carbon emission trends across western administrative regions： administrative regions with a relatively strong foundation in carbon reduction may warrant a moderate relaxation of regulatory measures， provided that industrial carbon emissions continue to decline without rebounding. For regions that have transitioned from the growth phase to the reduction phase of carbon emissions， sustained regulation of industrial carbon reduction is essential to further decrease emissions and ensure the achievement of carbon peak targets. Conversely， regions with a weaker foundation in carbon reduction require prioritized monitoring of industrial carbon emissions. Regulatory efforts in these areas should be continuously adjusted according to their specific carbon emission levels to enhance the effectiveness of reduction measures. 2） focus on regions with high carbon reduction potential： regions with significant carbon reduction potential should be prioritized for increased policy interventions， and this can be achieved by advancing technological capabilities， promoting clean energy development， and optimizing industrial structures.
2025, 43(5): 207-220.
doi: 10.13205/j.hjgc.202505023
Abstract:
Under the "dual carbon" goal， achieving carbon peaking and carbon neutrality in Guangxi has become an urgent issue for the entire region. From the perspective of industry heterogeneity， it is of great strategic significance to study the significant carbon emission drivers and conduct decoupling analysis for realizing the "dual carbon" goals and achieving green and low-carbon transformation of Guangxi's industrial sectors. Firstly， carbon emissions from Guangxi's industrial sub-sectors（2012—2022） were estimated based on their fossil energy consumption. Secondly， the LMDI model was used to establish a total of 12 effective driving factors in five categories of production， population， economy， trade， and energy， with their effects on industrial carbon emissions discussed from the perspective of positive and negative significant factors. Finally， the Tapio decoupling index was used to construct the decoupling elasticity between GDP and driving factors， and the relations between significant carbon emission factors and economic development were analyzed under the background of industrial carbon emissions and economic decoupling. The results showed that the total carbon emissions of Guangxi increased by 34.9% to 82.4667 million tonnes of CO2， while the carbon emission intensity decreased by 29.5%. The trends of all industries were similar to those observed in Guangxi overall. Among them， the industrial sector had the largest carbon emission base， and in 2022， only the transportation sector's and industrial sector's carbon emission intensities were 82.3% and 135.4% higher than the whole region， respectively. The total effects of the top two significant positive and negative factors in Guangxi as a whole and among industries showed similarities. Export and economic development were significant factors for increasing carbon emissions of industries， contributing 1154.06 million and 142.32 million tons of CO2， respectively. Technological advancement and energy intensity were the main factors to promote carbon emission reduction in the industry， with reductions of -98.0385 million and -60.199 million tons of CO2， respectively. However， there were some differences in the positive and negative significant factors affecting the industry in different periods. The GDP decoupling analysis showed that since 2021， Guangxi as a whole and all its industrial sectors predominantly exhibited negative decoupling； moreover， the decoupling status of significant factors remained relatively stable. This was specifically reflected in the fact that positive significant factors drove negative decoupling and linked decoupling types， while negative significant factors promoted positive decoupling types. It is suggested to intensify industrial adjustment， optimize the industrial energy consumption structure， promote low-carbon development by industry and focus， and adopt an overall planning to promote the rectification of the industry.
Under the "dual carbon" goal， achieving carbon peaking and carbon neutrality in Guangxi has become an urgent issue for the entire region. From the perspective of industry heterogeneity， it is of great strategic significance to study the significant carbon emission drivers and conduct decoupling analysis for realizing the "dual carbon" goals and achieving green and low-carbon transformation of Guangxi's industrial sectors. Firstly， carbon emissions from Guangxi's industrial sub-sectors（2012—2022） were estimated based on their fossil energy consumption. Secondly， the LMDI model was used to establish a total of 12 effective driving factors in five categories of production， population， economy， trade， and energy， with their effects on industrial carbon emissions discussed from the perspective of positive and negative significant factors. Finally， the Tapio decoupling index was used to construct the decoupling elasticity between GDP and driving factors， and the relations between significant carbon emission factors and economic development were analyzed under the background of industrial carbon emissions and economic decoupling. The results showed that the total carbon emissions of Guangxi increased by 34.9% to 82.4667 million tonnes of CO2， while the carbon emission intensity decreased by 29.5%. The trends of all industries were similar to those observed in Guangxi overall. Among them， the industrial sector had the largest carbon emission base， and in 2022， only the transportation sector's and industrial sector's carbon emission intensities were 82.3% and 135.4% higher than the whole region， respectively. The total effects of the top two significant positive and negative factors in Guangxi as a whole and among industries showed similarities. Export and economic development were significant factors for increasing carbon emissions of industries， contributing 1154.06 million and 142.32 million tons of CO2， respectively. Technological advancement and energy intensity were the main factors to promote carbon emission reduction in the industry， with reductions of -98.0385 million and -60.199 million tons of CO2， respectively. However， there were some differences in the positive and negative significant factors affecting the industry in different periods. The GDP decoupling analysis showed that since 2021， Guangxi as a whole and all its industrial sectors predominantly exhibited negative decoupling； moreover， the decoupling status of significant factors remained relatively stable. This was specifically reflected in the fact that positive significant factors drove negative decoupling and linked decoupling types， while negative significant factors promoted positive decoupling types. It is suggested to intensify industrial adjustment， optimize the industrial energy consumption structure， promote low-carbon development by industry and focus， and adopt an overall planning to promote the rectification of the industry.
2025, 43(5): 221-232.
doi: 10.13205/j.hjgc.202505024
Abstract:
The production and emission activities of a fluorochemical manufacturing facility have been identified as significant direct sources of per- and polyfluoroalkyl substances （PFAS） in the surrounding environment， which have attracted attention due to their persistence， bioaccumulation， and potential toxicity. PFAS contamination poses potential risks to ecological health and human well-being. This study focused on a typical electrochemical fluorination site in Hubei Province， China， investigating the concentration levels and spatial distribution of 17 PFAS in soil， interior building surfaces， and groundwater. The CSOIL model was also utilized to evaluate the potential human health risks associated with exposure to these chemicals. In this study， 13 types of PFAS were detected in soil， 17 on interior building surfaces， and 9 in groundwater. The total concentrations ranged from 882 to 282000 μg/kg （average： 54300 μg/kg） in soil， 45200 to 270000 μg/kg （average： 122000 μg/kg） on interior building surfaces， and 2060 to 3510 μg/L （average： 2550 μg/L） in groundwater. Perfluorobutanesulfonic acid（PFBS） was the predominant PFAS in soil， with an average concentration of 28200 μg/kg， accounting for 52.06% of the total， followed by perfluorooctanesulfonic acid（PFOS） at 16900 μg/kg （31.13%） and perfluorohexanesulfonic acid（PFHxS） at 5680 μg/kg （10.49%）. On building surfaces， PFOS was the most abundant at 38300 μg/kg （31.47%）， followed by perfluorohexanoic acid（PFHxA） at 24900 μg/kg （20.43%） and perfluorooctanoic acid（PFOA） at 21800 μg/kg （17.87%）. In groundwater， PFBS was the primary type at 14000 μg/kg （54.72%）， followed by PFHxS at 500 μg/kg （19.59%） and perfluorobutanoic acid（PFBA） at 239 μg/kg （9.36%）. These data revealed the distribution characteristics of PFAS in different environmental media， with PFBS and PFOS being the most significant pollutants. The human health risk assessment indicated that the intake of PFOS， PFBS， PFHxS， and PFOA by children and adults all exceeded the health guidance values， requiring significant attention. PFAS exposure routes are diverse， including food intake， drinking water， indoor air， and dust. Particularly， occupational exposure poses a significant health risk as workers come into direct contact with PFAS. In addition， PFAS can expose infants and young children through breast milk and indoor dust. These findings underscore the potential public health risks associated with PFAS contamination at the fluorochemical plant site， particularly for local residents who may be exposed through soil， water， and indoor environments. Consequently， further investigation and remediation are imperative to address the detrimental impacts on both the ecosystem and human health.
The production and emission activities of a fluorochemical manufacturing facility have been identified as significant direct sources of per- and polyfluoroalkyl substances （PFAS） in the surrounding environment， which have attracted attention due to their persistence， bioaccumulation， and potential toxicity. PFAS contamination poses potential risks to ecological health and human well-being. This study focused on a typical electrochemical fluorination site in Hubei Province， China， investigating the concentration levels and spatial distribution of 17 PFAS in soil， interior building surfaces， and groundwater. The CSOIL model was also utilized to evaluate the potential human health risks associated with exposure to these chemicals. In this study， 13 types of PFAS were detected in soil， 17 on interior building surfaces， and 9 in groundwater. The total concentrations ranged from 882 to 282000 μg/kg （average： 54300 μg/kg） in soil， 45200 to 270000 μg/kg （average： 122000 μg/kg） on interior building surfaces， and 2060 to 3510 μg/L （average： 2550 μg/L） in groundwater. Perfluorobutanesulfonic acid（PFBS） was the predominant PFAS in soil， with an average concentration of 28200 μg/kg， accounting for 52.06% of the total， followed by perfluorooctanesulfonic acid（PFOS） at 16900 μg/kg （31.13%） and perfluorohexanesulfonic acid（PFHxS） at 5680 μg/kg （10.49%）. On building surfaces， PFOS was the most abundant at 38300 μg/kg （31.47%）， followed by perfluorohexanoic acid（PFHxA） at 24900 μg/kg （20.43%） and perfluorooctanoic acid（PFOA） at 21800 μg/kg （17.87%）. In groundwater， PFBS was the primary type at 14000 μg/kg （54.72%）， followed by PFHxS at 500 μg/kg （19.59%） and perfluorobutanoic acid（PFBA） at 239 μg/kg （9.36%）. These data revealed the distribution characteristics of PFAS in different environmental media， with PFBS and PFOS being the most significant pollutants. The human health risk assessment indicated that the intake of PFOS， PFBS， PFHxS， and PFOA by children and adults all exceeded the health guidance values， requiring significant attention. PFAS exposure routes are diverse， including food intake， drinking water， indoor air， and dust. Particularly， occupational exposure poses a significant health risk as workers come into direct contact with PFAS. In addition， PFAS can expose infants and young children through breast milk and indoor dust. These findings underscore the potential public health risks associated with PFAS contamination at the fluorochemical plant site， particularly for local residents who may be exposed through soil， water， and indoor environments. Consequently， further investigation and remediation are imperative to address the detrimental impacts on both the ecosystem and human health.
2025, 43(5): 233-241.
doi: 10.13205/j.hjgc.202505025
Abstract:
Electrokinetic remediation combined with thermal activated persulfate oxidation is an effective remediation technology for most organic contaminations in low-permeability soil. The key to improving its repaire efficiency lies in enhancing the migration， mass transfer， and thermal activation efficiency of the oxidants in low-permeability medium. In this paper， the migration behavior of persulfate in low-permeability medium under direct current （DC） and the thermal activation of persulfate under alternating current （AC） were studied， respectively. The results showed that adopting "anode dosing" was more conducive to the migration of persulfate than adopting "cathode dosing". The current intensity and electroosmotic velocity of the reaction system were significantly improved by increasing DC voltage gradient. However， the electroosmotic coefficient was basically unchanged because it was primarily related to the basic properties of the medium and was not affected by experimental conditions. When the DC voltage gradient was set to 1 V/cm， the persulfate ion reached its maximum migration distance at 24 h. The maximum migration distance was 25.0 cm and the average concentration at the furthest distance was 5.70% of the initial dosing concentration. When the DC voltage gradient was set to 2 V/cm， persulfate ions were almost unable to migrate instead and only accumulated at S1 point， which was 3.0 cm away from the anode. Under these condition， the average concentration of persulfate ions at S1 point reached 15 times the initial dosing concentration. In addition， it was found that the higher the AC voltage gradient， the better the heating effect of the medium when applying AC electric field with different intensities. The heating effect of the middle part of the medium was better than that on both sides of the electrode， indicating that the temperature in the middle was higher than that on both sides. The thermal activation efficiency of persulfate increased correspondingly with the increase of medium temperature. Therefore， the higher the AC voltage gradient， the higher the thermal activation efficiency of persulfate. Within the framework of this research， setting the DC voltage to a lower intensity of 1 V/cm and the AC voltage to a higher intensity of 3 V/cm resulted in the best migration effect of persulfate. Under this optimal condition， the maximum migration and diffusion distance reached 25.0 cm， and the thermal activation efficiency of persulfate ranged from 32.0% to 74.1%.
Electrokinetic remediation combined with thermal activated persulfate oxidation is an effective remediation technology for most organic contaminations in low-permeability soil. The key to improving its repaire efficiency lies in enhancing the migration， mass transfer， and thermal activation efficiency of the oxidants in low-permeability medium. In this paper， the migration behavior of persulfate in low-permeability medium under direct current （DC） and the thermal activation of persulfate under alternating current （AC） were studied， respectively. The results showed that adopting "anode dosing" was more conducive to the migration of persulfate than adopting "cathode dosing". The current intensity and electroosmotic velocity of the reaction system were significantly improved by increasing DC voltage gradient. However， the electroosmotic coefficient was basically unchanged because it was primarily related to the basic properties of the medium and was not affected by experimental conditions. When the DC voltage gradient was set to 1 V/cm， the persulfate ion reached its maximum migration distance at 24 h. The maximum migration distance was 25.0 cm and the average concentration at the furthest distance was 5.70% of the initial dosing concentration. When the DC voltage gradient was set to 2 V/cm， persulfate ions were almost unable to migrate instead and only accumulated at S1 point， which was 3.0 cm away from the anode. Under these condition， the average concentration of persulfate ions at S1 point reached 15 times the initial dosing concentration. In addition， it was found that the higher the AC voltage gradient， the better the heating effect of the medium when applying AC electric field with different intensities. The heating effect of the middle part of the medium was better than that on both sides of the electrode， indicating that the temperature in the middle was higher than that on both sides. The thermal activation efficiency of persulfate increased correspondingly with the increase of medium temperature. Therefore， the higher the AC voltage gradient， the higher the thermal activation efficiency of persulfate. Within the framework of this research， setting the DC voltage to a lower intensity of 1 V/cm and the AC voltage to a higher intensity of 3 V/cm resulted in the best migration effect of persulfate. Under this optimal condition， the maximum migration and diffusion distance reached 25.0 cm， and the thermal activation efficiency of persulfate ranged from 32.0% to 74.1%.
