The migration/transformation characteristics of heavy metals and polycyclic aromatic hydrocarbons(PAHs) during the co-liquefaction of pig manure and rice straw/wood sawdust were explored in this study.More than 87% of...The migration/transformation characteristics of heavy metals and polycyclic aromatic hydrocarbons(PAHs) during the co-liquefaction of pig manure and rice straw/wood sawdust were explored in this study.More than 87% of the heavy metals in feedstocks were enriched in hydrochars.The decreased proportion of active heavy metals in the hydrochars suggested partial passivation of the heavy metals.The pollution degree and risk of heavy metals were significantly mitigated from high and considerable levels in pig manure to moderate and low levels in hydrochar,respectively.Compared with commercial diesel,bio-oil products still contained an undesirable amount of heavy metals.PAHs were re-synthesized during liquefaction,with a net synthesis amount of 29.65-73.98 mg·kg^(-1).Moreover,the PAHs mainly existed in bio-oils,with a content of 57.32-132.33 mg·kg^(-1) and a toxicity equivalent of3.25-8.19 mg·kg^(-1).Compared to pig manure,the hydrochars presented a lower content of PAHs(1.76-3.53 mg·kg^(-1) versus 3.73 mg·kg^(-1)) and a smaller toxicity equivalent(0.14-0.22 mg·kg^(-1) versus0.26 mg·kg^(-1)).Interestingly,introducing lignocellulose(especially for rice straw) during the liquefaction of pig manure further mitigated the pollution degree/risk of heavy metals and PAHs.Overall,hydrochar reached a safe utilization level,while bio-oil products needed further clarification.展开更多
Manganese ion(Mn^(2+))was generated from metallurgical,steel making and chemical industries.It could affect microbial activity and community structure after entering sewage treatment plant.The effect of Mn^(2+)on the ...Manganese ion(Mn^(2+))was generated from metallurgical,steel making and chemical industries.It could affect microbial activity and community structure after entering sewage treatment plant.The effect of Mn^(2+)on the pollutant removal,metal distribution patterns and composition of microbial communities were investigated in a an anaerobic/anoxic/oxic(A^(2)O)process.The results showed that when Mn^(2+)concentration was 5 mg/L,the efficiencies for the removal of chemical oxygen demand(COD),total nitrogen(TN)and total phosphorus(TP)attained remarkable levels of 96%,93%,and 99%,respectively.In the sludge,the distribution pattern of Mn^(2+)concentration was tightly bound extracellular polymeric substances(TB-EPS)>supernatant>loosely bound EPS(LB-EPS)>soluble microbial products(SMP).Mn^(2+)was found to enrich and accumulate in the microorganism cells.In addition,Mn^(2+)was mainly found in residual fractions and reducible fractions of pellet that manganese was present.The pellet was discovered to contain a substantial quantity of manganese,which was present in various oxidation states,including Mn^(4+),Mn^(3+)and Mn^(2+).The escalating levels of Mn^(2+)led to a reduction in the richness and diversity of microbial communities inhabiting various regions of the A^(2)O reactor.Nonetheless,the uniformity experienced only subtle alterations.Proteobacteria and Bacteroidetes emerged as the leading phyla within the microbial ecosystem,experiencing a steady rise in their respective proportions.The dominant bacterial groups,Azospira and Dechromonas,experienced an incremental increase in their relative prevalence,which played a constructive role in the process of pollutant removal.展开更多
Recently,more and more attention has been paid to the strong oxidation ability of newly prepared potassium ferrate(NAPF) in sludge reduction process,but less attention has been paid to the change of phosphorus in this...Recently,more and more attention has been paid to the strong oxidation ability of newly prepared potassium ferrate(NAPF) in sludge reduction process,but less attention has been paid to the change of phosphorus in this process.The feasibility of phosphorus migration and transformation during excess sludge reduction pretre atment using NAPF pre-oxidation combined with anaerobic digestion was investigated.After 70 mg/g suspended solids NAPF pretreatment and 16 days anaerobic digestion,the solid-phase volatile suspended solids decreased by 44.2%,and much organic matter had been released into the liquid-phase and then degraded during digestion by indigenous microorganisms.As the sludge pre-oxidation process was performed,solid-phase organic phosphorus and chemically combined phosphorus also released into the liquid-phase as PO4^3-,peaking at 100 mg/L.During anaerobic digestion,the Fe3+in the liquid-phase was gradually reduced to Fe2+,and then formed Fe^2+-PO4^3- compound crystals and re-migrated to the solid-phase.The concentration of PO4^3- decreased to 17.08± 1.1 mg/L in the liquid-phase after anaerobic digestion.Finally,the phosphorus in the Fe^2+-PO4^3- compound accounts for 80% of the total phosphorus in the solid-phase.A large number of vivianite crystals in sludge were observed.Therefore,this technology not only effectively reduces sludge,but also increases the proportion of PO43-in the sludge in the form of Vivianite.展开更多
Collecting waste water with a certain c onc entration of organic pollutants COD (chemical oxygen demand), static adsorption, static biodegradation and dynamic soil column experiments were made in laborato ry, we rese...Collecting waste water with a certain c onc entration of organic pollutants COD (chemical oxygen demand), static adsorption, static biodegradation and dynamic soil column experiments were made in laborato ry, we researched migration and transformation of COD in aerated zone, and put f orward a mathematical model showing the process. The results show that adsorptio n of organism in aerated zone is linear, which is represented by Henry's law s =K dc+s d, adsorption coefficient K d=0.069 3; biodegradati on diagram accord basically with first order kinetics equation c=c 0e -K 1t , biodegradation coefficient K 1 = 0.049 9 d -1 ; dispersio n coefficient D= 0.002 42 m 2/d in experiments. The migration and transform ation of organic pollutants (COD) in aerated zone jointly result from many f actors such as dispersion, adsorption and biodegradation etc..展开更多
[Objective] The aim was to provide theoretical basis for field moisture conserving irrigation.[Method] With Xiaoyan No.6 as tested material,three different kinds of mulching irrigation treatments were carried out （st...[Objective] The aim was to provide theoretical basis for field moisture conserving irrigation.[Method] With Xiaoyan No.6 as tested material,three different kinds of mulching irrigation treatments were carried out （straw mulching;plastic mulching;PAM control adjustment mulching）.With non-mulching treatment as control,moisture conserving effect of different treatments were compared.[Result] The results showed that the water consumption of winter wheat under different soil moisture conservation treatments was low at earlier stage and later stage,but high at mid-stage,which was consistent with the water consumption law of control.There were some differences in terms of consumption intensity because of irrigation schedule and growth condition;soil moisture conservation treatments could restrain ineffective evaporation of soil moisture before anthesis.We also found that the variation of soil moisture at depth of 0-20 cm in PAM and control treatment was dramatic.The soil moisture of the former was lower than the latter at the depth of 0-20 cm,but higher at the depth of 20-50 cm.The difference of soil moisture at the depth of 0-50 cm was significant.[Conclusion] Plastic mulching and straw mulching could restrain evaporation effectively.展开更多
Leakage of electrolytic manganese slag(EMS)ponds is a long-lasting and serious threat to environmental health worldwide,particularly in karst areas where the ecosystems are highly sensitive to geochemical perturbation...Leakage of electrolytic manganese slag(EMS)ponds is a long-lasting and serious threat to environmental health worldwide,particularly in karst areas where the ecosystems are highly sensitive to geochemical perturbations.However,the mechanisms of Mn mobilization and migration are insufficiently known.In this study,we combine systematic field investigations,laboratory column experiments and geochemical analyses to clarify the environmental geochemistry and controlling factors of leaching of Mn in the karst areas of southwestern China.While the Mn slag ponds as a whole had shown a low permeability,release of free Mn^(2+)and NH_(3)-N is significantly facilitated by the synergies of seepage infiltration,microbial activities and environmental acidification.With the increase of depth,the mineralogical composition of the slag undergoes significant alteration,and redox conditions change from acidic-oxidizing to acidic-reducing environments,which will accelerate the mobilization of Mn further and increase the risk of groundwater contamination.In addition,the presence of clay mineral colloids in Mn slag changes the migration properties of Mn,which introduces complexity in the geochemical behavior of Mn.Our findings highlight that Mn transformation and migration are controlled by dynamic,depth-dependent geochemical processes and the interplay of both internal and external factors.This research consolidates mechanistic foundation of deciphering Mn environmental behaviors in karst regions,reinforcing the urgency of preventing and rehabilitating electrolytic Mn slag leakage.展开更多
Pharmaceuticals and personal care products(PPCPs)are a new kind of contaminant widely existing in the surface water and groundwater environment.In recent years,PPCPs have been received widely attention from many resea...Pharmaceuticals and personal care products(PPCPs)are a new kind of contaminant widely existing in the surface water and groundwater environment.In recent years,PPCPs have been received widely attention from many researchers.The migration and transformation of PPCPs are mainly photolysis,biodegradation,adsorption and hydrolysis in aquifer environment.The influencing factors of PPCPs migration include PPCPs’own physical and chemical properties,types and contents of organic matter,pH,lithology,geotechnical structure and the thickness of vadose zone,etc.At present,the research of PPCPs in China is still in the primary stage,especially on the contaminant in aquifer system.Therefore,the research in this field needs to be further strengthened.展开更多
Controlling heavy metal pollution in agricultural soil has been a significant challenge.These heavy metals seriously threaten the surrounding ecological environment and human health.The effective assessment and remedi...Controlling heavy metal pollution in agricultural soil has been a significant challenge.These heavy metals seriously threaten the surrounding ecological environment and human health.The effective assessment and remediation of heavy metals in agricultural soils are crucial.These two aspects support each other,forming a close and complete decisionmaking chain.Therefore,this review systematically summarizes the distribution characteristics of soil heavy metal pollution,the correlation between soil and crop heavy metal contents,the presence pattern and migration and transformation mode of heavy metals in the soil-crop system.The advantages and disadvantages of the risk evaluation tools and models of heavy metal pollution in farmland are further outlined,which provides important guidance for an in-depth understanding of the characteristics of heavymetal pollution in farmland soils and the assessment of the environmental risk.Soil remediation strategies involve multiple physical,chemical,biological and even combined technologies,and this paper compares the potential and effect of the above current remediation technologies in heavy metal polluted farmland soils.Finally,the main problems and possible research directions of future heavy metal risk assessment and remediation technologies in agricultural soils are prospected.This review provides new ideas for effective assessment and selection of remediation technologies based on the characterization of soil heavy metals.展开更多
The Qinghai-Tibet Plateau,with its high altitude and cold climate,is one of the most fragile ecological environments in China and is distinguished by its naturally elevated arsenic(As)levels in the soil,largely due to...The Qinghai-Tibet Plateau,with its high altitude and cold climate,is one of the most fragile ecological environments in China and is distinguished by its naturally elevated arsenic(As)levels in the soil,largely due to its rich mineral and geothermal resources.This review provides a comprehensive analysis of As content,focusing on its distribution,environmental migration,and transformation behavior across the plateau.The review further evaluates the distribution of As in different functional areas,revealing that geothermal fields(107.2 mg/kg),mining areas(53.8 mg/kg),and croplands(39.3 mg/kg)have the highest As concentrations,followed by river and lake sediments and adjacent areas(33.1 mg/kg).These elevated levels are primarily attributed to the presence of As-rich minerals,such as arsenopyrite and pyrite.Additionally,human activities,including mining and geothermal energy production,exacerbate the release of As into the environment.The review also highlights the role of localmicroorganisms,particularly those fromthe phyla Proteobacteria and Actinobacteria,which possess As metabolic genes that facilitate As translocation.Given the unique climatic conditions of the plateau,conventionalmethods for As controlmay not be fully effective.However,the review identifies promising remediation strategies that are environmentally adaptable,such as the use of local microorganisms,specific adsorbents,and integrated technologies,which offer potential solutions for managing and utilizing Ascontaminated soils on the plateau.展开更多
Cyclic injection holds great potential for CO_(2) emission reduction coupled with enhanced unconventional oil recovery.There is,however,a lack of a thorough understanding of carbon distribution,migration,and transform...Cyclic injection holds great potential for CO_(2) emission reduction coupled with enhanced unconventional oil recovery.There is,however,a lack of a thorough understanding of carbon distribution,migration,and transformation underground over time at the reservoir scale.To address this issue,we conducted a rig-orous numerical simulation integrating microseismic events,multi-geomechanics,and multi-geochemistry to represent the complex fracture geometry,rock stress sensitivity,and CO_(2)-oil-brine-rock interactions.The fluid model,reservoir model,and geochemical reaction kinetics were carefully validated and calibrated using experimental data.The performance of CO_(2) utilization and geological storage was comprehensively investigated in terms of changes in oil production,CO_(2) storage,carbon distribution,and petrophysical properties.The results indicate that 48.3%of the injected CO_(2) was stored stably under-ground after ten cycles(ten years),with a 3.4%increase in oil recovery.The presence of multiple CO_(2) stor-age forms,such as dissolved in water and mineralized carbonate,impeded CO_(2)-oil interaction,leading to a 25.9%reduction in the volume of the CO_(2)-oil mixing zone and a 2.2%decrease in cumulative oil pro-duction,albeit with a 7.7%increase in the storage rate.The cyclic injection mode had a significant impact on the migration and transformation of CO_(2) in the reservoir.While dissolved CO_(2) in oil accounted for over half of the total storage,it had the possibility of being released during production.After ten cycles,20%of the injected CO_(2)(approximately 12000 t)reached long-term storage in four forms:mineralized carbon-ate(6%),water-dissolved CO_(2)(6%),aqueous ions(4%),and trapped gas(4%).Notably,the non-fracture zone within the stimulated reservoir volume(SRV)served as the primary trapping area for residual gas.This work provides valuable insights into dynamic CO_(2) transport and transformation processes under cyclic injection and presents a more comprehensive and precise framework for assessing CO_(2) capture,utilization,and storage with enhanced oil recovery(CCUS-EOR)performance in unconventional reser-voirs after fracturing.展开更多
Lanthanum-based oxides are promising candidates for low-temperature oxidative coupling of methane(OCM).To further lower the OCM reaction temperature,the Ce doped flower-like La_(2)O_(2)CO_(3)microsphere catalysts were...Lanthanum-based oxides are promising candidates for low-temperature oxidative coupling of methane(OCM).To further lower the OCM reaction temperature,the Ce doped flower-like La_(2)O_(2)CO_(3)microsphere catalysts were synthesized,achieving a significantly low reaction temperature (375℃) while maintaining high C_(2) hydrocarbon selectivity (43.0%).Doping Ce into the lattice of La_(2)O_(2)CO_(3)created more surface oxygen vacancies and bulk lattice defects,which was in favor of the transformation and migration of oxygen species at 350–400℃.The designed H_(2) temperature-programmed reduction (H_(2)-TPR) experiments provided strong evidence that the low reaction temperature of La_(x)Ce_(1-x)O_(1.5+δ)can be attributed to the transformation and migration of oxygen species,which dynamically generated surface oxygen vacancies for continuous oxygen activation to selectively convert methane.Moreover,designed temperatureprogrammed surface reaction (TPSR) clarified that two kinds of surface oxygen species in La_(x)Ce_(1-x)O_(1.5+δ)catalysts were concerned with catalytic performance,that is,the surface chemisorbed oxygen species for the activation of CH_(2)and the formation of CH_(2)·intermediates,surface La-Ce-O lattice oxygen species that caused the excessive oxidation of CH_(2)·intermediates.Finally,the factors affecting the transformation and migration of oxygen species were explored.展开更多
Metal-based engineered nanomaterials(MENMs)are increasingly being used in people’s working lives.Although MENMs have important effects on soil ecosystem and play an important role in solving soil environmental proble...Metal-based engineered nanomaterials(MENMs)are increasingly being used in people’s working lives.Although MENMs have important effects on soil ecosystem and play an important role in solving soil environmental problems,the hazards associated with MENMs cannot be ignored.Therefore,more and more scholars have studied the behavior and effects of nanomaterials in soils in recent years.In this review,we explore the articles on MENMs and soil ecosystem retrieved from various databases from 2013 to 2022.We discuss the mechanisms of MENM toxicity,the current state of soil ecosystem,the ecological effects of MENMs on soil microbes,earthworms,and plants,and the ways by which soil organisms take up MENMs.We now know that although MENMs have positive effects on soil ecosystem,their potential hazards are not negligible.Therefore,it is necessary to investigate the effects of MENMs on soil organisms.Meanwhile,we should pay more attention to the negative effects of MENMs on soil ecosystem while exploring their positive effects on soil ecosystem in future research.展开更多
A temporary profile from Shiquan in the southern part of Shaanxi Province to Ningxian in Gansu Province for observation of geomagnetic short period variations was set up. The characteristics of geomagnetic short perio...A temporary profile from Shiquan in the southern part of Shaanxi Province to Ningxian in Gansu Province for observation of geomagnetic short period variations was set up. The characteristics of geomagnetic short period variations in the profile region was analyzed through geomagnetic transfer functions at measurement sites (Fan, et al, 1998). According to the theory of multi-scale analysis of wavelet transform, the components affected by regional origin in the region is extracted in this paper. The components of regional origin is used as original data in the inversion study for investigation of 2-D conductivity structure corresponding to the regional origin. The inversion method (Zhdanov, Traynin, 1997) which is based on the minimum of the total energy of the residual field between observational electro-magnetic field and the calculated theoretical field of conductivity model and the conception of migrated residual field is introduced into our inversion of the data of magneto-variation sounding. The result of the inversion gives the underground conductivity structure in depth range of 100 km beneath the profile, and shows that a high conductivity area is located under Wugong and Qianling. The main characteristics of the inversion method is briefly discussed, that is, it can reflect the depth and the distribution of anomalous conductivity area comparatively well, and large number of parameters of inversion model is allowed to be used in the Inversion.展开更多
基金supported by the National Natural Science Foundation of China(21707056)the Natural Science Foundation of Jiangxi Province,China(20192BAB203019)the Jiangxi Province Graduate Innovation Special Fund Project(YC2022-S412)。
文摘The migration/transformation characteristics of heavy metals and polycyclic aromatic hydrocarbons(PAHs) during the co-liquefaction of pig manure and rice straw/wood sawdust were explored in this study.More than 87% of the heavy metals in feedstocks were enriched in hydrochars.The decreased proportion of active heavy metals in the hydrochars suggested partial passivation of the heavy metals.The pollution degree and risk of heavy metals were significantly mitigated from high and considerable levels in pig manure to moderate and low levels in hydrochar,respectively.Compared with commercial diesel,bio-oil products still contained an undesirable amount of heavy metals.PAHs were re-synthesized during liquefaction,with a net synthesis amount of 29.65-73.98 mg·kg^(-1).Moreover,the PAHs mainly existed in bio-oils,with a content of 57.32-132.33 mg·kg^(-1) and a toxicity equivalent of3.25-8.19 mg·kg^(-1).Compared to pig manure,the hydrochars presented a lower content of PAHs(1.76-3.53 mg·kg^(-1) versus 3.73 mg·kg^(-1)) and a smaller toxicity equivalent(0.14-0.22 mg·kg^(-1) versus0.26 mg·kg^(-1)).Interestingly,introducing lignocellulose(especially for rice straw) during the liquefaction of pig manure further mitigated the pollution degree/risk of heavy metals and PAHs.Overall,hydrochar reached a safe utilization level,while bio-oil products needed further clarification.
基金supported by Jilin Provincial Department of Education Science and Technology Project(No.JJKH20230152KJ)the Doctoral Research Initiation Fund(No.BSJXM-2022215).
文摘Manganese ion(Mn^(2+))was generated from metallurgical,steel making and chemical industries.It could affect microbial activity and community structure after entering sewage treatment plant.The effect of Mn^(2+)on the pollutant removal,metal distribution patterns and composition of microbial communities were investigated in a an anaerobic/anoxic/oxic(A^(2)O)process.The results showed that when Mn^(2+)concentration was 5 mg/L,the efficiencies for the removal of chemical oxygen demand(COD),total nitrogen(TN)and total phosphorus(TP)attained remarkable levels of 96%,93%,and 99%,respectively.In the sludge,the distribution pattern of Mn^(2+)concentration was tightly bound extracellular polymeric substances(TB-EPS)>supernatant>loosely bound EPS(LB-EPS)>soluble microbial products(SMP).Mn^(2+)was found to enrich and accumulate in the microorganism cells.In addition,Mn^(2+)was mainly found in residual fractions and reducible fractions of pellet that manganese was present.The pellet was discovered to contain a substantial quantity of manganese,which was present in various oxidation states,including Mn^(4+),Mn^(3+)and Mn^(2+).The escalating levels of Mn^(2+)led to a reduction in the richness and diversity of microbial communities inhabiting various regions of the A^(2)O reactor.Nonetheless,the uniformity experienced only subtle alterations.Proteobacteria and Bacteroidetes emerged as the leading phyla within the microbial ecosystem,experiencing a steady rise in their respective proportions.The dominant bacterial groups,Azospira and Dechromonas,experienced an incremental increase in their relative prevalence,which played a constructive role in the process of pollutant removal.
基金supported by the National Natural Science Foundation of China(No.51938010)the Major Science and Technology Projects for Water Pollution Control and Treatment of China(No.2017ZX07205002)+1 种基金National Key Research and Development Programme of China(No.2016YFC0401103)the Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment。
文摘Recently,more and more attention has been paid to the strong oxidation ability of newly prepared potassium ferrate(NAPF) in sludge reduction process,but less attention has been paid to the change of phosphorus in this process.The feasibility of phosphorus migration and transformation during excess sludge reduction pretre atment using NAPF pre-oxidation combined with anaerobic digestion was investigated.After 70 mg/g suspended solids NAPF pretreatment and 16 days anaerobic digestion,the solid-phase volatile suspended solids decreased by 44.2%,and much organic matter had been released into the liquid-phase and then degraded during digestion by indigenous microorganisms.As the sludge pre-oxidation process was performed,solid-phase organic phosphorus and chemically combined phosphorus also released into the liquid-phase as PO4^3-,peaking at 100 mg/L.During anaerobic digestion,the Fe3+in the liquid-phase was gradually reduced to Fe2+,and then formed Fe^2+-PO4^3- compound crystals and re-migrated to the solid-phase.The concentration of PO4^3- decreased to 17.08± 1.1 mg/L in the liquid-phase after anaerobic digestion.Finally,the phosphorus in the Fe^2+-PO4^3- compound accounts for 80% of the total phosphorus in the solid-phase.A large number of vivianite crystals in sludge were observed.Therefore,this technology not only effectively reduces sludge,but also increases the proportion of PO43-in the sludge in the form of Vivianite.
文摘Collecting waste water with a certain c onc entration of organic pollutants COD (chemical oxygen demand), static adsorption, static biodegradation and dynamic soil column experiments were made in laborato ry, we researched migration and transformation of COD in aerated zone, and put f orward a mathematical model showing the process. The results show that adsorptio n of organism in aerated zone is linear, which is represented by Henry's law s =K dc+s d, adsorption coefficient K d=0.069 3; biodegradati on diagram accord basically with first order kinetics equation c=c 0e -K 1t , biodegradation coefficient K 1 = 0.049 9 d -1 ; dispersio n coefficient D= 0.002 42 m 2/d in experiments. The migration and transform ation of organic pollutants (COD) in aerated zone jointly result from many f actors such as dispersion, adsorption and biodegradation etc..
基金Supported by National 863 Project (2006AA100223)Program of Introducing Talents of Discipline to Hydrology Ecological and Water Security in Arid and Semi Arid Areas(B08039)~~
文摘[Objective] The aim was to provide theoretical basis for field moisture conserving irrigation.[Method] With Xiaoyan No.6 as tested material,three different kinds of mulching irrigation treatments were carried out （straw mulching;plastic mulching;PAM control adjustment mulching）.With non-mulching treatment as control,moisture conserving effect of different treatments were compared.[Result] The results showed that the water consumption of winter wheat under different soil moisture conservation treatments was low at earlier stage and later stage,but high at mid-stage,which was consistent with the water consumption law of control.There were some differences in terms of consumption intensity because of irrigation schedule and growth condition;soil moisture conservation treatments could restrain ineffective evaporation of soil moisture before anthesis.We also found that the variation of soil moisture at depth of 0-20 cm in PAM and control treatment was dramatic.The soil moisture of the former was lower than the latter at the depth of 0-20 cm,but higher at the depth of 20-50 cm.The difference of soil moisture at the depth of 0-50 cm was significant.[Conclusion] Plastic mulching and straw mulching could restrain evaporation effectively.
基金financially supported by the National Natural Science Foundation of China(No.42077184)Guizhou Institute of Technology's Research Initiation Fund Project for High-Level Talents(No.XJGC20190602)。
文摘Leakage of electrolytic manganese slag(EMS)ponds is a long-lasting and serious threat to environmental health worldwide,particularly in karst areas where the ecosystems are highly sensitive to geochemical perturbations.However,the mechanisms of Mn mobilization and migration are insufficiently known.In this study,we combine systematic field investigations,laboratory column experiments and geochemical analyses to clarify the environmental geochemistry and controlling factors of leaching of Mn in the karst areas of southwestern China.While the Mn slag ponds as a whole had shown a low permeability,release of free Mn^(2+)and NH_(3)-N is significantly facilitated by the synergies of seepage infiltration,microbial activities and environmental acidification.With the increase of depth,the mineralogical composition of the slag undergoes significant alteration,and redox conditions change from acidic-oxidizing to acidic-reducing environments,which will accelerate the mobilization of Mn further and increase the risk of groundwater contamination.In addition,the presence of clay mineral colloids in Mn slag changes the migration properties of Mn,which introduces complexity in the geochemical behavior of Mn.Our findings highlight that Mn transformation and migration are controlled by dynamic,depth-dependent geochemical processes and the interplay of both internal and external factors.This research consolidates mechanistic foundation of deciphering Mn environmental behaviors in karst regions,reinforcing the urgency of preventing and rehabilitating electrolytic Mn slag leakage.
基金This study was supported by National Natural Science Foundation of China(No.4197021272).
文摘Pharmaceuticals and personal care products(PPCPs)are a new kind of contaminant widely existing in the surface water and groundwater environment.In recent years,PPCPs have been received widely attention from many researchers.The migration and transformation of PPCPs are mainly photolysis,biodegradation,adsorption and hydrolysis in aquifer environment.The influencing factors of PPCPs migration include PPCPs’own physical and chemical properties,types and contents of organic matter,pH,lithology,geotechnical structure and the thickness of vadose zone,etc.At present,the research of PPCPs in China is still in the primary stage,especially on the contaminant in aquifer system.Therefore,the research in this field needs to be further strengthened.
基金supported by the National Natural Science Foundation of China(Nos.52100184,and U22A20617).
文摘Controlling heavy metal pollution in agricultural soil has been a significant challenge.These heavy metals seriously threaten the surrounding ecological environment and human health.The effective assessment and remediation of heavy metals in agricultural soils are crucial.These two aspects support each other,forming a close and complete decisionmaking chain.Therefore,this review systematically summarizes the distribution characteristics of soil heavy metal pollution,the correlation between soil and crop heavy metal contents,the presence pattern and migration and transformation mode of heavy metals in the soil-crop system.The advantages and disadvantages of the risk evaluation tools and models of heavy metal pollution in farmland are further outlined,which provides important guidance for an in-depth understanding of the characteristics of heavymetal pollution in farmland soils and the assessment of the environmental risk.Soil remediation strategies involve multiple physical,chemical,biological and even combined technologies,and this paper compares the potential and effect of the above current remediation technologies in heavy metal polluted farmland soils.Finally,the main problems and possible research directions of future heavy metal risk assessment and remediation technologies in agricultural soils are prospected.This review provides new ideas for effective assessment and selection of remediation technologies based on the characterization of soil heavy metals.
基金supported by the Central Public-interest Scientific Institution Basal Research Fund(No.Y2024QC29)the Central Public-interest Scientific Institution Basal Research Fund(Nos.2024-jbkyywf-lwj and 2024-jbkyywf-zyj).
文摘The Qinghai-Tibet Plateau,with its high altitude and cold climate,is one of the most fragile ecological environments in China and is distinguished by its naturally elevated arsenic(As)levels in the soil,largely due to its rich mineral and geothermal resources.This review provides a comprehensive analysis of As content,focusing on its distribution,environmental migration,and transformation behavior across the plateau.The review further evaluates the distribution of As in different functional areas,revealing that geothermal fields(107.2 mg/kg),mining areas(53.8 mg/kg),and croplands(39.3 mg/kg)have the highest As concentrations,followed by river and lake sediments and adjacent areas(33.1 mg/kg).These elevated levels are primarily attributed to the presence of As-rich minerals,such as arsenopyrite and pyrite.Additionally,human activities,including mining and geothermal energy production,exacerbate the release of As into the environment.The review also highlights the role of localmicroorganisms,particularly those fromthe phyla Proteobacteria and Actinobacteria,which possess As metabolic genes that facilitate As translocation.Given the unique climatic conditions of the plateau,conventionalmethods for As controlmay not be fully effective.However,the review identifies promising remediation strategies that are environmentally adaptable,such as the use of local microorganisms,specific adsorbents,and integrated technologies,which offer potential solutions for managing and utilizing Ascontaminated soils on the plateau.
基金support from the National Key Research and Development Program of China(2023YFE0120700)National Natural Science Foundation of China(52274041)Distinguished Young Sichuan Science Scholars(2023NSFSC1954).
文摘Cyclic injection holds great potential for CO_(2) emission reduction coupled with enhanced unconventional oil recovery.There is,however,a lack of a thorough understanding of carbon distribution,migration,and transformation underground over time at the reservoir scale.To address this issue,we conducted a rig-orous numerical simulation integrating microseismic events,multi-geomechanics,and multi-geochemistry to represent the complex fracture geometry,rock stress sensitivity,and CO_(2)-oil-brine-rock interactions.The fluid model,reservoir model,and geochemical reaction kinetics were carefully validated and calibrated using experimental data.The performance of CO_(2) utilization and geological storage was comprehensively investigated in terms of changes in oil production,CO_(2) storage,carbon distribution,and petrophysical properties.The results indicate that 48.3%of the injected CO_(2) was stored stably under-ground after ten cycles(ten years),with a 3.4%increase in oil recovery.The presence of multiple CO_(2) stor-age forms,such as dissolved in water and mineralized carbonate,impeded CO_(2)-oil interaction,leading to a 25.9%reduction in the volume of the CO_(2)-oil mixing zone and a 2.2%decrease in cumulative oil pro-duction,albeit with a 7.7%increase in the storage rate.The cyclic injection mode had a significant impact on the migration and transformation of CO_(2) in the reservoir.While dissolved CO_(2) in oil accounted for over half of the total storage,it had the possibility of being released during production.After ten cycles,20%of the injected CO_(2)(approximately 12000 t)reached long-term storage in four forms:mineralized carbon-ate(6%),water-dissolved CO_(2)(6%),aqueous ions(4%),and trapped gas(4%).Notably,the non-fracture zone within the stimulated reservoir volume(SRV)served as the primary trapping area for residual gas.This work provides valuable insights into dynamic CO_(2) transport and transformation processes under cyclic injection and presents a more comprehensive and precise framework for assessing CO_(2) capture,utilization,and storage with enhanced oil recovery(CCUS-EOR)performance in unconventional reser-voirs after fracturing.
基金the Shanxi Science and Technology Department bidding project(No.20191101012)the autonomous research project of SKLCC(No.2020BWZ003)for providing financial support。
文摘Lanthanum-based oxides are promising candidates for low-temperature oxidative coupling of methane(OCM).To further lower the OCM reaction temperature,the Ce doped flower-like La_(2)O_(2)CO_(3)microsphere catalysts were synthesized,achieving a significantly low reaction temperature (375℃) while maintaining high C_(2) hydrocarbon selectivity (43.0%).Doping Ce into the lattice of La_(2)O_(2)CO_(3)created more surface oxygen vacancies and bulk lattice defects,which was in favor of the transformation and migration of oxygen species at 350–400℃.The designed H_(2) temperature-programmed reduction (H_(2)-TPR) experiments provided strong evidence that the low reaction temperature of La_(x)Ce_(1-x)O_(1.5+δ)can be attributed to the transformation and migration of oxygen species,which dynamically generated surface oxygen vacancies for continuous oxygen activation to selectively convert methane.Moreover,designed temperatureprogrammed surface reaction (TPSR) clarified that two kinds of surface oxygen species in La_(x)Ce_(1-x)O_(1.5+δ)catalysts were concerned with catalytic performance,that is,the surface chemisorbed oxygen species for the activation of CH_(2)and the formation of CH_(2)·intermediates,surface La-Ce-O lattice oxygen species that caused the excessive oxidation of CH_(2)·intermediates.Finally,the factors affecting the transformation and migration of oxygen species were explored.
基金supported by the National Key R&D Program of China(Nos.2017YFD0801300 and 2017YFD 0801103)the National Natural Science Foundation of China(No.41130526)。
文摘Metal-based engineered nanomaterials(MENMs)are increasingly being used in people’s working lives.Although MENMs have important effects on soil ecosystem and play an important role in solving soil environmental problems,the hazards associated with MENMs cannot be ignored.Therefore,more and more scholars have studied the behavior and effects of nanomaterials in soils in recent years.In this review,we explore the articles on MENMs and soil ecosystem retrieved from various databases from 2013 to 2022.We discuss the mechanisms of MENM toxicity,the current state of soil ecosystem,the ecological effects of MENMs on soil microbes,earthworms,and plants,and the ways by which soil organisms take up MENMs.We now know that although MENMs have positive effects on soil ecosystem,their potential hazards are not negligible.Therefore,it is necessary to investigate the effects of MENMs on soil organisms.Meanwhile,we should pay more attention to the negative effects of MENMs on soil ecosystem while exploring their positive effects on soil ecosystem in future research.
文摘A temporary profile from Shiquan in the southern part of Shaanxi Province to Ningxian in Gansu Province for observation of geomagnetic short period variations was set up. The characteristics of geomagnetic short period variations in the profile region was analyzed through geomagnetic transfer functions at measurement sites (Fan, et al, 1998). According to the theory of multi-scale analysis of wavelet transform, the components affected by regional origin in the region is extracted in this paper. The components of regional origin is used as original data in the inversion study for investigation of 2-D conductivity structure corresponding to the regional origin. The inversion method (Zhdanov, Traynin, 1997) which is based on the minimum of the total energy of the residual field between observational electro-magnetic field and the calculated theoretical field of conductivity model and the conception of migrated residual field is introduced into our inversion of the data of magneto-variation sounding. The result of the inversion gives the underground conductivity structure in depth range of 100 km beneath the profile, and shows that a high conductivity area is located under Wugong and Qianling. The main characteristics of the inversion method is briefly discussed, that is, it can reflect the depth and the distribution of anomalous conductivity area comparatively well, and large number of parameters of inversion model is allowed to be used in the Inversion.
