Iron-based amorphous crystalline powder Fe_(78)Si_(9)B_(13)^(AP)is used as a permeability reaction barrier(PRB)combined with an electrokinetic method(EK-PRB)to study the removal rate of Cu in contaminated soil.After t...Iron-based amorphous crystalline powder Fe_(78)Si_(9)B_(13)^(AP)is used as a permeability reaction barrier(PRB)combined with an electrokinetic method(EK-PRB)to study the removal rate of Cu in contaminated soil.After treating Cucontaminated soil for 5 days under different voltage gradients and soil water content,the soil pH is between 3.1 and 7.2.The increase of voltage gradient and soil water content can effectively promote the movement of Cu^(2+) to the cathode.The voltage gradient is 3 V/cm,and the water content of 40%is considered to be an optional experimental condition.Therefore,under this condition,the effects of Fe_(78)Si_(9)B_(13)^(AP)and zero-valent iron(ZVI)as PRB on the removal rate of total Cu in soil and the transformation of chemical forms of Cu are studied.Compared with ZVI,Fe_(78)Si_(9)B_(13)^(AP)as PRB has a better remediation effect.EK-Fe_(78)Si_(9)B_(13)^(AP)can remove 80.3%of total Cu in soil,and the biologically available Cu is reduced to 3.6%,which effectively reduces the environmental risk of contaminated soil.展开更多
The long-term oil exploitation in oil fields has led to pollution of surrounding soil, creating a serious ecological problem. In order to promote and improve the application of microbial remediation in oil contaminate...The long-term oil exploitation in oil fields has led to pollution of surrounding soil, creating a serious ecological problem. In order to promote and improve the application of microbial remediation in oil contaminated soil, experiment is carried out in polluted area in Zhongyuan Oilfield. In the experiment, indigenous microorganisms and other physical and chemical methods are employed, ryegrass is grown, and environmental factors in soil are regulated to degrade the oil and treat the polluted soil. Results show that when the average oil content in the soil is about 523.08 mg/kg, 65 days' remediation through plants and microorganisms could help bring the oil content down to 74.61 mg/kg, achieving a degradation rate of 85.74%; through salinity treatment, salt content in soil is reduced by 62.93-82.03% to 399-823 mg/kg from previous 2.22 g/kg. Through this experiment, the bioremediation method is improved and its effectiveness and feasibility are testified. The result has been applied in Zhongyuan Oilfield and has brought fair ecological and economic benefits, providing technical support to the treatment of contaminated soil of the same kind, and offering some insights to the treatment of soil contaminated by other organic pollutants.展开更多
Diesel contaminated soil(DCS) contained a large amount of the hydrocarbons and salt which was dominated by soluble sodium chloride. Aggregation process which made the desired aggregate size distribution could speed up...Diesel contaminated soil(DCS) contained a large amount of the hydrocarbons and salt which was dominated by soluble sodium chloride. Aggregation process which made the desired aggregate size distribution could speed up the degradation rate of the hydrocarbons since the aggregated DCS had better physical characteristics than the non-aggregated material. Artificial aggregation increased pores >30 μm by approximately 5% and reduced pores <1 μm by 5%, but did not change the percentage of the pores between 1 and 30 μm. The saturated hydraulic conductivity of non-aggregated DCS was 5×10-6 m · s-l, but it increased to 1×10-5 m · s-l after aggregation. The compression index of the non-aggregated DCS was 0.0186; however, the artificial aggregates with and without lime were 0.031 and 0.028, respectively. DCS could be piled 0.2 m deep without artificial aggregation; however, it could be applied 0.28 m deep when artificial aggregates were formed without limiting O2 transport.展开更多
Plant uptake of contaminants provides vital information for the reclamation of large area of contaminated soils.A field experiment was conducted using four plant species growing in four kinds of oil contaminated soils...Plant uptake of contaminants provides vital information for the reclamation of large area of contaminated soils.A field experiment was conducted using four plant species growing in four kinds of oil contaminated soils to estimate the uptake of organic and inorganic contaminants by plants from the oil contaminated soils.The experiment showed that the concentrations of some selected elements,such as B,Co and Ni in plants growing in the oil contaminated soils were significantly higher than those in plants growing in the uncontaminated control soil.The accumulation of metals in plants increased with plant biomass;however,the removal of metals by plants from the oil contaminated soils was not practical.展开更多
Bioremediation involving bioaugmentation and biostimulation are eco-friendly existing methods for degrading polycyclic aromatic hydrocarbons (PAHs) in contaminated soils. This study investigates the efficiency of Pseu...Bioremediation involving bioaugmentation and biostimulation are eco-friendly existing methods for degrading polycyclic aromatic hydrocarbons (PAHs) in contaminated soils. This study investigates the efficiency of Pseudomonas auriginosa and nutrient-enriched sawdust (SD) in biodegrading ∑PAHs in contaminated soil (CS). Four compost mixtures of CS/SD (1:0, 3:1, 1:1, 1:3) were applied for 2, 4, 6, 8-week bio-cleanup after inoculation. Results show ∑PAHs concentrations decreased with increasing time of treatment for all four compost in experimental and control setups. The removal efficiency of ∑PAHs was clearly associated with nutrient-enriched sawdust and Pseudomonas auriginosa, especially for 3:1, 1:1, and 1:3 ratios. Both factors had a significant effect (p = 0.05) on removal efficiency compared to the control setup. The highest (78.5%) and lowest (37.8%) ∑PAHs removal efficiency were observed for CS/SD ratios of 1:3 and 1:0 respectively after 8-week treatment. In this instance, this study recommends a CS/SD ratio of 1:3 at 8-week treatment to achieve maximum removal efficiency of ∑PAHs in contaminated soils.展开更多
Persulfate is considered a convenient and efficient remediation agent for organic contaminated soil.However,the potential risk of sulfur into the soil remediation by persulfate remains ignored.In this study,glass bott...Persulfate is considered a convenient and efficient remediation agent for organic contaminated soil.However,the potential risk of sulfur into the soil remediation by persulfate remains ignored.In this study,glass bottles with different persulfate dosages and groundwater tables were set up to simulate persulfate remediation of organic pollutants(aniline).The results found sulfate to be the main end-product(83.0%–99.5%)of persulfate remediation after10 days.Moreover,H_(2)S accounted for 93.4%–99.4%of sulfur reduction end-products,suggesting that H_(2)S was the final fate of sulfur.H_(2)S was released rapidly after one to three days at a maximum concentration of 33.0 ppm,which is sufficient to make a person uncomfortable.According to the fitted curve results,H_(2)S concentration decreased to a safe concentration(0.15 ppm)after 20–85 days.Meanwhile,the maximum concentration of methanethiol reached 0.6 ppm.These results indicated that secondary pollution from persulfate remediation could release harmful gases over a long time.Therefore,persulfate should be used more carefully as a remediation agent for soil contamination.展开更多
High energy consumption is a serious issue associated with in situ thermal desorption(TD)remediation of sites contaminated by petroleum hydrocarbons(PHs).The knowledge on the thermophysical properties of contaminated ...High energy consumption is a serious issue associated with in situ thermal desorption(TD)remediation of sites contaminated by petroleum hydrocarbons(PHs).The knowledge on the thermophysical properties of contaminated soil can help predict accurately the transient temperature distribution in a remediation site,for the purpose of energy conservation.However,such data are rarely reported for PH-contaminated soil.In this study,by taking diesel as a representative example for PHs,soil samples with constant dry bulk density but different diesel mass concentrations ranging from 0% to 20% were prepared,and the variations of their thermal conductivity,specific heat capacity and thermal diffusivity were measured and analyzed over a wide temperature range between 0℃ and 120℃.It was found that the effect of diesel concentration on the thermal conductivity of soil is negligible when it is below 1%.When diesel concentration is below 10%,the thermal conductivity of soil increases with raising the temperature.However,when diesel concentration becomes above 10%,the change of the thermal conductivity of soil with temperature exhibits the opposite trend.This is mainly due to the competition between soil minerals and diesel,because the thermal conductivity of minerals increases with temperature,whereas the thermal conductivity of diesel decreases with temperature.The analysis results showed that,compared with temperature,the diesel concentration has more significant effects on soil thermal conductivity.Regardless of the diesel concentration,with the increase of temperature,the specific heat capacity of soil increases,while the thermal diffusivity of soil decreases.In addition,the results of a control experiment exhibited that the relative differences of the thermal conductivity of the soil samples containing the same concentration of both diesel and a pure alkane are all below 10%,indicating that the results obtained with diesel in this study can be extended to the family of PHs.A theoretical prediction model was proposed based on cubic fractal and thermal resistance analysis,which confirmed that diesel concentration does have a significant effect on soil thermal conductivity.For the sake of practical applications,a regression model with the diesel concentration as a primary parameter was also proposed.展开更多
The global problem of petroleum contamination in soils seriously threatens environmental safety and human health.Current studies have successfully demonstrated the feasibility of bioelectrokinetic and bioelectrochemic...The global problem of petroleum contamination in soils seriously threatens environmental safety and human health.Current studies have successfully demonstrated the feasibility of bioelectrokinetic and bioelectrochemical remediation of petroleum-contaminated soils due to their easy implementation,environmental benignity,and enhanced removal efficiency compared to bioremediation.This paper reviewed recent progress and development associated with bioelectrokinetic and bioelectrochemical remediation of petroleum-contaminated soils.The working principles,removal efficiencies,affecting factors,and constraints of the two technologies were thoroughly summarized and discussed.The potentials,challenges,and future perspectives were also deliberated to shed light on how to overcome the barriers and realize widespread implementation on large scales of these two technologies.展开更多
Cadmium contamination of soil is a global issue and in-situ remediation technology as a promising mitigation strategy has attracted more and more attention.Many nanomaterials have been applied for the in-situ remediat...Cadmium contamination of soil is a global issue and in-situ remediation technology as a promising mitigation strategy has attracted more and more attention.Many nanomaterials have been applied for the in-situ remediation of cadmium-contaminated soil due to their excellent properties of the nano-scale size effect.In this work,recent research progress of various nanomaterials,including carbon nanomaterials,metal-based nanomaterials and nano mineral materials,in the removal of cadmium and in-situ remediation of cadmiumcontaminated soil were systematically discussed.Additional emphases were particularly laid on both laboratory and field restoration effects.Moreover,the factors which can affect the stability of cadmium,main interaction mechanisms between nanomaterials and cadmium in the soil,and potential future research direction were also provided.Therefore,it is believed that this work will ultimately contribute to the myriad of environmental cleanup advances,and further improve human health and sustainable development.展开更多
Organic contaminated soils have become a widespread environmental problem,which may lead to a great threat to the quality of agricultural production and to human health.Physical,chemical,and biological technologies ha...Organic contaminated soils have become a widespread environmental problem,which may lead to a great threat to the quality of agricultural production and to human health.Physical,chemical,and biological technologies have been employed for the mitigation and remediation of organic contaminated soils.This paper reviews the progress of mitigation and remediation technologies for organic contaminated soils and suggests two different strategies for the mitigation of‘slightlycontaminated’agricultural soils and the remediation of‘heavily-contaminated’soils/sites,respectively.On this basis,directions for future research in this field are suggested.展开更多
Risk associated with heavy metals in soil has been received widespread attention.In this study,a porous biochar supported nanoscale zero-valent iron(BC-nZVI)was applied to immobilize cadmium(Cd)and lead(Pb)in clayey s...Risk associated with heavy metals in soil has been received widespread attention.In this study,a porous biochar supported nanoscale zero-valent iron(BC-nZVI)was applied to immobilize cadmium(Cd)and lead(Pb)in clayey soil.Experiment results indicated that the immobilization of Cd or Pb by BC-nZVI process was better than that of BC or nZVI process,and about 80%of heavy metals immobilization was obtained in BC-nZVI process.Addition of BC-nZVI could increase soil pH and organic matter(SOM).Cd or Pb immobilization was inhibited with coexisting organic compound 2,4-dichlorophenol(2,4-DCP),but 2,4-DCP could be removed in a simultaneous manner with Cd or Pb immobilization at low concentration levels.Simultaneous immobilization of Cd and Pb was achieved in BC-nZVI process,and both Cd and Pb availability significantly decreased.Stable Cd species inculding Cd(OH)_(2),CdCO_(3)and CdO were formed,whereas stable Pb species such as PbCO_(3),PbO and Pb(OH)_(2)were produced with BC-nZVI treatment.Simultaneous immobilization mechanism of Cd and Pb in soil by BC-nZVI was thereby proposed.This study well demonstrates that BC-nZVI has been emerged as a potential technology for the remediation of multiple heavy metals in soil.展开更多
Urban soils polluted with heavy metals are of increasing concern because it is greatly affecting human health and the ecological systems.Hence,it is mandatory to understand the reasons behind this pollution and remedi...Urban soils polluted with heavy metals are of increasing concern because it is greatly affecting human health and the ecological systems.Hence,it is mandatory to understand the reasons behind this pollution and remediate the contaminated solid.The removal of heavy metals from contaminated soil samples collected from the vicinity of the sewage lake in Jeddah,Saudi Arabia,was explored.The leaching process was studied kinetically and thermodynamically for better understanding of the remediation process.The results showed that the soil samples were slightly basic in nature,and tend to be more neutral away from the main contaminated sewage lake area.The total metal content in the soil samples was measured using the aqua regia extractions by ICPOES and the results showed that many of the heavy metals present have significant concentrations above the tolerable limits.In general,the metal concentrations at different sites indicated that the heavy metal pollution is mainly due to the sewage discharge to the lake.The results showed excellent correlation between the concentrations of Co,As,and Hg with the distance from the main contaminated area.The leaching of Co,As,and Hg using 1.0 M hydrochloric acid from the soil was studied kinetically at different temperatures and the experimental results were fitted using different kinetics models.The experimental data were best described with two-constant rate and Elovich equation kinetic models.Also,the thermodynamic study showed that the leaching process was spontaneous,endothermic and accompanied with increase in the entropy.In general,the polluted soil could be remediated successfully from the heavy metals using the acid leaching procedure in a short period of time.展开更多
Stabilization is one of the best demonstrated available technologies for treating toxic pollutants in soils and has been used worldwide but is rarely used for treatment of contaminated sites in China despite many benc...Stabilization is one of the best demonstrated available technologies for treating toxic pollutants in soils and has been used worldwide but is rarely used for treatment of contaminated sites in China despite many bench-scale studies.Here,a field-scale application of stabilization treatment in Shanghai,China was summarized to demonstrate the whole engineering process and the key technical issues regarding stabilization of contaminated soil.A site contaminated with arsenic(As)and polycyclic aromatic hydrocarbons(PAHs),formerly used as a lighting plant in Shanghai,was chosen as the demonstration site.Stabilizing measures were taken to treat the contaminated soil to reuse the site for residential purposes.The whole engineering remediation process consisted of phase I environmental site assessment(ESA)and phase II ESA,quantitative human health risk assessment,remediation alternatives evaluation,benchscale testing,remedial design,engineering implementation,and post-remediation assessment.A third party conducted evaluation monitoring indicated desirable results were achieved via the stabilization treatment.In addition,some technical obstacles related to soil stabilization treatment were discussed,including soil quality evaluation,stabilization effectiveness validation,and soil reuse assessment.展开更多
Land is used for agricultural production, industrial development, urban construction, and environmental beautification, thus soil environment is an important component of living ecosystems for human survival.……
This study explored the effectiveness and mechanisms of high temperature sintering following prereduction with ferric sulfate(FeSO_(4)),sodium sulfide(Na_(2)S),or citric acid(C_(6)H_(8)O_(7))in stabilizing hexavalent ...This study explored the effectiveness and mechanisms of high temperature sintering following prereduction with ferric sulfate(FeSO_(4)),sodium sulfide(Na_(2)S),or citric acid(C_(6)H_(8)O_(7))in stabilizing hexavalent chromium(Cr(VI))in highly contaminated soil.The soil samples had an initial total Cr leaching of 1768.83 mg/L,and Cr(VI)leaching of 1745.13 mg/L.When FeSO_(4)or C_(6)H_(8)O_(7)reduction was followed by sintering at 1000℃,the Cr leaching was reduced enough to meet the Safety Landfill Standards regarding general industrial solid waste.This combined treatment greatly improved the stabilization efficiency of chromium because the reduction of Cr(VI)into Cr(III)decreased the mobility of chromium and made it more easily encapsulated in minerals during sintering.SEM,XRD,TG-DSC,and speciation analysis indicated that when the sintering temperature reached 1000℃,almost all the chromium in soils that had the pre-reduction treatment was transformed into the residual form.At 1000℃,the soil melted and promoted the mineralization of Cr and the formation of new Cr-containing compounds,which significantly decreased subsequent leaching of chromium from the soil.However,without reduction treatment,chromium continued to leach from the soil even after being sintered at 1000℃,possibly because the soil did not fully fuse and because Cr(VI)does not bind with soil as easily as Cr(III).展开更多
The present work deals with the development of an Ontology-Based Knowledge Network of soil/water physicochemical & biological properties (soil/water concepts), derived from ASTM Standard Methods (ASTMi,n) and rele...The present work deals with the development of an Ontology-Based Knowledge Network of soil/water physicochemical & biological properties (soil/water concepts), derived from ASTM Standard Methods (ASTMi,n) and relevant scientific/applicable references (published papers—PPi,n) to fill up/bridge the gap of the information science between cited Standards and infiltration discipline conceptual vocabulary providing accordingly a dedicated/internal Knowledge Base (KB). This attempt constitutes an innovative approach, since it is based on externalizing domain knowledge in the form of Ontology-Based Knowledge Networks, incorporating standardized methodology in soil engineering. The ontology soil/water concepts (semantics) of the developed network correspond to soil/water physicochemical & biological properties, classified in seven different generations that are distinguished/located in infiltration/percolation process of contaminated water through soil porous media. The interconnections with arcs between corresponding concepts/properties among the consecutive generations are defined by the relationship of dependent and independent variables. All these interconnections are documented according to the below three ways: 1) dependent and independent variables interconnected by using the logical operator “<em>depends on</em>” quoting existent explicit functions and equations;2) dependent and independent variables interconnected by using the logical operator “<em>depends on</em>” quoting produced implicit functions, according to Rayleigh’s method of indices;3) dependent and independent variables interconnected by using the logical operator “<em>related to</em>” based on a logical dependence among the examined nodes-concepts-variables. The aforementioned approach provides significant advantages to semantic web developers and web users by means of prompt knowledge navigation, tracking, retrieval and usage.展开更多
The present study was designed to assess lead levels in playground soil and accumulated dust on playground equipment and then correlate those environmental lead measurements with children’s blood lead in the surround...The present study was designed to assess lead levels in playground soil and accumulated dust on playground equipment and then correlate those environmental lead measurements with children’s blood lead in the surrounding neighborhoods. Soil lead and surface dust were collected from 14 playgrounds in Muncie, Indiana, and blood lead levels were calculated for nearby children. Correlation analyses revealed a moderate positive association between dust Pb and soil Pb with a correlation coefficient r = 0.46 (p = 0.099). The relationship between settled dust on playground equipment and composite blood lead level also showed a medium positive correlation, indicated by r = 0.36 (p = 0.202). A positive correlation was also observed between soil Pb and composite blood lead values, as evidenced by r = 0.51 (p = 0.061). Furthermore, the assessment of spatial autocorrelation using Moran’s I index indicated no significant spatial clustering for the variables studied (dust Pb, soil Pb, and blood Pb). Correlation analysis showed a connection between lead levels in soil and dust, but no significant links were found between soil lead and blood lead and between dust lead and blood lead. These results suggest that environmental lead in parks has a limited impact on children’s blood lead levels nearby. Spatial autocorrelation analysis also revealed no significant spatial patterns among variables—dust, soil, and blood lead. Given these findings, it is recommended to seek expertise from qualified professionals and further perform comprehensive testing and analysis to investigate potential lead sources in children’s blood. The outcomes of this study offer valuable insights into assessing playground environmental lead contamination, contributing to future research priorities in this area. Specifically, future studies could focus on collecting larger sample sizes and characterizing blood lead in children who frequently use playgrounds rather than those who live nearby but may or may not use the playgrounds.展开更多
基金This research was funded by the National Natural Science Foundation of China(NSFC)[Grant Nos.51661015 and 52061024]the University Innovation Fund Project of Gansu Provincial Department of Education[Grant No.2021B-553]the Natural Science Foundation of Zhejiang Province,China(4304030).
文摘Iron-based amorphous crystalline powder Fe_(78)Si_(9)B_(13)^(AP)is used as a permeability reaction barrier(PRB)combined with an electrokinetic method(EK-PRB)to study the removal rate of Cu in contaminated soil.After treating Cucontaminated soil for 5 days under different voltage gradients and soil water content,the soil pH is between 3.1 and 7.2.The increase of voltage gradient and soil water content can effectively promote the movement of Cu^(2+) to the cathode.The voltage gradient is 3 V/cm,and the water content of 40%is considered to be an optional experimental condition.Therefore,under this condition,the effects of Fe_(78)Si_(9)B_(13)^(AP)and zero-valent iron(ZVI)as PRB on the removal rate of total Cu in soil and the transformation of chemical forms of Cu are studied.Compared with ZVI,Fe_(78)Si_(9)B_(13)^(AP)as PRB has a better remediation effect.EK-Fe_(78)Si_(9)B_(13)^(AP)can remove 80.3%of total Cu in soil,and the biologically available Cu is reduced to 3.6%,which effectively reduces the environmental risk of contaminated soil.
基金funded by The basic scientific research project fund of Chinese Academy of Geological Sciences (Code: YYWF201519)China Geology Survey Work Program (Code: 121201106000150006)+1 种基金The international cooperation project of Ministry of Science and Technology (Code: 2005DFA90200)Mine environment management project of Henan Provincial Department of Land and Resources
文摘The long-term oil exploitation in oil fields has led to pollution of surrounding soil, creating a serious ecological problem. In order to promote and improve the application of microbial remediation in oil contaminated soil, experiment is carried out in polluted area in Zhongyuan Oilfield. In the experiment, indigenous microorganisms and other physical and chemical methods are employed, ryegrass is grown, and environmental factors in soil are regulated to degrade the oil and treat the polluted soil. Results show that when the average oil content in the soil is about 523.08 mg/kg, 65 days' remediation through plants and microorganisms could help bring the oil content down to 74.61 mg/kg, achieving a degradation rate of 85.74%; through salinity treatment, salt content in soil is reduced by 62.93-82.03% to 399-823 mg/kg from previous 2.22 g/kg. Through this experiment, the bioremediation method is improved and its effectiveness and feasibility are testified. The result has been applied in Zhongyuan Oilfield and has brought fair ecological and economic benefits, providing technical support to the treatment of contaminated soil of the same kind, and offering some insights to the treatment of soil contaminated by other organic pollutants.
文摘Diesel contaminated soil(DCS) contained a large amount of the hydrocarbons and salt which was dominated by soluble sodium chloride. Aggregation process which made the desired aggregate size distribution could speed up the degradation rate of the hydrocarbons since the aggregated DCS had better physical characteristics than the non-aggregated material. Artificial aggregation increased pores >30 μm by approximately 5% and reduced pores <1 μm by 5%, but did not change the percentage of the pores between 1 and 30 μm. The saturated hydraulic conductivity of non-aggregated DCS was 5×10-6 m · s-l, but it increased to 1×10-5 m · s-l after aggregation. The compression index of the non-aggregated DCS was 0.0186; however, the artificial aggregates with and without lime were 0.031 and 0.028, respectively. DCS could be piled 0.2 m deep without artificial aggregation; however, it could be applied 0.28 m deep when artificial aggregates were formed without limiting O2 transport.
文摘Plant uptake of contaminants provides vital information for the reclamation of large area of contaminated soils.A field experiment was conducted using four plant species growing in four kinds of oil contaminated soils to estimate the uptake of organic and inorganic contaminants by plants from the oil contaminated soils.The experiment showed that the concentrations of some selected elements,such as B,Co and Ni in plants growing in the oil contaminated soils were significantly higher than those in plants growing in the uncontaminated control soil.The accumulation of metals in plants increased with plant biomass;however,the removal of metals by plants from the oil contaminated soils was not practical.
文摘Bioremediation involving bioaugmentation and biostimulation are eco-friendly existing methods for degrading polycyclic aromatic hydrocarbons (PAHs) in contaminated soils. This study investigates the efficiency of Pseudomonas auriginosa and nutrient-enriched sawdust (SD) in biodegrading ∑PAHs in contaminated soil (CS). Four compost mixtures of CS/SD (1:0, 3:1, 1:1, 1:3) were applied for 2, 4, 6, 8-week bio-cleanup after inoculation. Results show ∑PAHs concentrations decreased with increasing time of treatment for all four compost in experimental and control setups. The removal efficiency of ∑PAHs was clearly associated with nutrient-enriched sawdust and Pseudomonas auriginosa, especially for 3:1, 1:1, and 1:3 ratios. Both factors had a significant effect (p = 0.05) on removal efficiency compared to the control setup. The highest (78.5%) and lowest (37.8%) ∑PAHs removal efficiency were observed for CS/SD ratios of 1:3 and 1:0 respectively after 8-week treatment. In this instance, this study recommends a CS/SD ratio of 1:3 at 8-week treatment to achieve maximum removal efficiency of ∑PAHs in contaminated soils.
基金supported by the National Key R&D Program of China (No.2018YFC1800506)the Key R&D Program of Zhejiang Province (No.2020C03083)。
文摘Persulfate is considered a convenient and efficient remediation agent for organic contaminated soil.However,the potential risk of sulfur into the soil remediation by persulfate remains ignored.In this study,glass bottles with different persulfate dosages and groundwater tables were set up to simulate persulfate remediation of organic pollutants(aniline).The results found sulfate to be the main end-product(83.0%–99.5%)of persulfate remediation after10 days.Moreover,H_(2)S accounted for 93.4%–99.4%of sulfur reduction end-products,suggesting that H_(2)S was the final fate of sulfur.H_(2)S was released rapidly after one to three days at a maximum concentration of 33.0 ppm,which is sufficient to make a person uncomfortable.According to the fitted curve results,H_(2)S concentration decreased to a safe concentration(0.15 ppm)after 20–85 days.Meanwhile,the maximum concentration of methanethiol reached 0.6 ppm.These results indicated that secondary pollution from persulfate remediation could release harmful gases over a long time.Therefore,persulfate should be used more carefully as a remediation agent for soil contamination.
基金financially supported by the National Key Research and Development Program (project No.2019YFC1805700,program No.2019YFC1805701)。
文摘High energy consumption is a serious issue associated with in situ thermal desorption(TD)remediation of sites contaminated by petroleum hydrocarbons(PHs).The knowledge on the thermophysical properties of contaminated soil can help predict accurately the transient temperature distribution in a remediation site,for the purpose of energy conservation.However,such data are rarely reported for PH-contaminated soil.In this study,by taking diesel as a representative example for PHs,soil samples with constant dry bulk density but different diesel mass concentrations ranging from 0% to 20% were prepared,and the variations of their thermal conductivity,specific heat capacity and thermal diffusivity were measured and analyzed over a wide temperature range between 0℃ and 120℃.It was found that the effect of diesel concentration on the thermal conductivity of soil is negligible when it is below 1%.When diesel concentration is below 10%,the thermal conductivity of soil increases with raising the temperature.However,when diesel concentration becomes above 10%,the change of the thermal conductivity of soil with temperature exhibits the opposite trend.This is mainly due to the competition between soil minerals and diesel,because the thermal conductivity of minerals increases with temperature,whereas the thermal conductivity of diesel decreases with temperature.The analysis results showed that,compared with temperature,the diesel concentration has more significant effects on soil thermal conductivity.Regardless of the diesel concentration,with the increase of temperature,the specific heat capacity of soil increases,while the thermal diffusivity of soil decreases.In addition,the results of a control experiment exhibited that the relative differences of the thermal conductivity of the soil samples containing the same concentration of both diesel and a pure alkane are all below 10%,indicating that the results obtained with diesel in this study can be extended to the family of PHs.A theoretical prediction model was proposed based on cubic fractal and thermal resistance analysis,which confirmed that diesel concentration does have a significant effect on soil thermal conductivity.For the sake of practical applications,a regression model with the diesel concentration as a primary parameter was also proposed.
基金This work was partially supported by grants from the National Natural Science Foundation of China(No.52270029)the Tianshan Youth Project of Xinjiang Uygur Autonomous Region(No.2020Q050)the Key Research and Development Projects of Shaanxi Province(No.2018ZDCXL-SF-31-6).
文摘The global problem of petroleum contamination in soils seriously threatens environmental safety and human health.Current studies have successfully demonstrated the feasibility of bioelectrokinetic and bioelectrochemical remediation of petroleum-contaminated soils due to their easy implementation,environmental benignity,and enhanced removal efficiency compared to bioremediation.This paper reviewed recent progress and development associated with bioelectrokinetic and bioelectrochemical remediation of petroleum-contaminated soils.The working principles,removal efficiencies,affecting factors,and constraints of the two technologies were thoroughly summarized and discussed.The potentials,challenges,and future perspectives were also deliberated to shed light on how to overcome the barriers and realize widespread implementation on large scales of these two technologies.
基金supported by the National Key Research and Development Program(2018YFD0800300,2016YFC1400600)Natural Science Foundation of China(U1607111)+3 种基金the Hundred Talent program of CAS(2010–735)the Project for Science and Technology Service of Chinese Academy of Sciences(KFJ-EWSTS-016)Ningbo Natural Science Foundation(202003N4002)the Zhejiang Province Financial Support(LGF19D060001,R5110230)。
文摘Cadmium contamination of soil is a global issue and in-situ remediation technology as a promising mitigation strategy has attracted more and more attention.Many nanomaterials have been applied for the in-situ remediation of cadmium-contaminated soil due to their excellent properties of the nano-scale size effect.In this work,recent research progress of various nanomaterials,including carbon nanomaterials,metal-based nanomaterials and nano mineral materials,in the removal of cadmium and in-situ remediation of cadmiumcontaminated soil were systematically discussed.Additional emphases were particularly laid on both laboratory and field restoration effects.Moreover,the factors which can affect the stability of cadmium,main interaction mechanisms between nanomaterials and cadmium in the soil,and potential future research direction were also provided.Therefore,it is believed that this work will ultimately contribute to the myriad of environmental cleanup advances,and further improve human health and sustainable development.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.20890111,20737002,and 40973067).
文摘Organic contaminated soils have become a widespread environmental problem,which may lead to a great threat to the quality of agricultural production and to human health.Physical,chemical,and biological technologies have been employed for the mitigation and remediation of organic contaminated soils.This paper reviews the progress of mitigation and remediation technologies for organic contaminated soils and suggests two different strategies for the mitigation of‘slightlycontaminated’agricultural soils and the remediation of‘heavily-contaminated’soils/sites,respectively.On this basis,directions for future research in this field are suggested.
基金supported by the Special project in key areas of Guangdong Province Ordinary Universities (No. 2020ZDZX1003)the Guangdong Provincial Key R&D Programme (No. 2020B1111350002)+4 种基金the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (2018)the research project and development plan for key areas of Guangdong Province (No. 2020B0202080002)the Project of Educational Commission of Guangdong Province of China (No. 2019KTSCX067)the Guangdong Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams (No. 2019KJ140)the National Natural Science Foundation of China (No. 21407155).
文摘Risk associated with heavy metals in soil has been received widespread attention.In this study,a porous biochar supported nanoscale zero-valent iron(BC-nZVI)was applied to immobilize cadmium(Cd)and lead(Pb)in clayey soil.Experiment results indicated that the immobilization of Cd or Pb by BC-nZVI process was better than that of BC or nZVI process,and about 80%of heavy metals immobilization was obtained in BC-nZVI process.Addition of BC-nZVI could increase soil pH and organic matter(SOM).Cd or Pb immobilization was inhibited with coexisting organic compound 2,4-dichlorophenol(2,4-DCP),but 2,4-DCP could be removed in a simultaneous manner with Cd or Pb immobilization at low concentration levels.Simultaneous immobilization of Cd and Pb was achieved in BC-nZVI process,and both Cd and Pb availability significantly decreased.Stable Cd species inculding Cd(OH)_(2),CdCO_(3)and CdO were formed,whereas stable Pb species such as PbCO_(3),PbO and Pb(OH)_(2)were produced with BC-nZVI treatment.Simultaneous immobilization mechanism of Cd and Pb in soil by BC-nZVI was thereby proposed.This study well demonstrates that BC-nZVI has been emerged as a potential technology for the remediation of multiple heavy metals in soil.
文摘Urban soils polluted with heavy metals are of increasing concern because it is greatly affecting human health and the ecological systems.Hence,it is mandatory to understand the reasons behind this pollution and remediate the contaminated solid.The removal of heavy metals from contaminated soil samples collected from the vicinity of the sewage lake in Jeddah,Saudi Arabia,was explored.The leaching process was studied kinetically and thermodynamically for better understanding of the remediation process.The results showed that the soil samples were slightly basic in nature,and tend to be more neutral away from the main contaminated sewage lake area.The total metal content in the soil samples was measured using the aqua regia extractions by ICPOES and the results showed that many of the heavy metals present have significant concentrations above the tolerable limits.In general,the metal concentrations at different sites indicated that the heavy metal pollution is mainly due to the sewage discharge to the lake.The results showed excellent correlation between the concentrations of Co,As,and Hg with the distance from the main contaminated area.The leaching of Co,As,and Hg using 1.0 M hydrochloric acid from the soil was studied kinetically at different temperatures and the experimental results were fitted using different kinetics models.The experimental data were best described with two-constant rate and Elovich equation kinetic models.Also,the thermodynamic study showed that the leaching process was spontaneous,endothermic and accompanied with increase in the entropy.In general,the polluted soil could be remediated successfully from the heavy metals using the acid leaching procedure in a short period of time.
文摘Stabilization is one of the best demonstrated available technologies for treating toxic pollutants in soils and has been used worldwide but is rarely used for treatment of contaminated sites in China despite many bench-scale studies.Here,a field-scale application of stabilization treatment in Shanghai,China was summarized to demonstrate the whole engineering process and the key technical issues regarding stabilization of contaminated soil.A site contaminated with arsenic(As)and polycyclic aromatic hydrocarbons(PAHs),formerly used as a lighting plant in Shanghai,was chosen as the demonstration site.Stabilizing measures were taken to treat the contaminated soil to reuse the site for residential purposes.The whole engineering remediation process consisted of phase I environmental site assessment(ESA)and phase II ESA,quantitative human health risk assessment,remediation alternatives evaluation,benchscale testing,remedial design,engineering implementation,and post-remediation assessment.A third party conducted evaluation monitoring indicated desirable results were achieved via the stabilization treatment.In addition,some technical obstacles related to soil stabilization treatment were discussed,including soil quality evaluation,stabilization effectiveness validation,and soil reuse assessment.
文摘 Land is used for agricultural production, industrial development, urban construction, and environmental beautification, thus soil environment is an important component of living ecosystems for human survival.……
基金This research was supported by the National Key R&D Program of China(Grant No.2018YFD0800604).We would also like to thank the team members of our laboratory for their valuable discussions.
文摘This study explored the effectiveness and mechanisms of high temperature sintering following prereduction with ferric sulfate(FeSO_(4)),sodium sulfide(Na_(2)S),or citric acid(C_(6)H_(8)O_(7))in stabilizing hexavalent chromium(Cr(VI))in highly contaminated soil.The soil samples had an initial total Cr leaching of 1768.83 mg/L,and Cr(VI)leaching of 1745.13 mg/L.When FeSO_(4)or C_(6)H_(8)O_(7)reduction was followed by sintering at 1000℃,the Cr leaching was reduced enough to meet the Safety Landfill Standards regarding general industrial solid waste.This combined treatment greatly improved the stabilization efficiency of chromium because the reduction of Cr(VI)into Cr(III)decreased the mobility of chromium and made it more easily encapsulated in minerals during sintering.SEM,XRD,TG-DSC,and speciation analysis indicated that when the sintering temperature reached 1000℃,almost all the chromium in soils that had the pre-reduction treatment was transformed into the residual form.At 1000℃,the soil melted and promoted the mineralization of Cr and the formation of new Cr-containing compounds,which significantly decreased subsequent leaching of chromium from the soil.However,without reduction treatment,chromium continued to leach from the soil even after being sintered at 1000℃,possibly because the soil did not fully fuse and because Cr(VI)does not bind with soil as easily as Cr(III).
文摘The present work deals with the development of an Ontology-Based Knowledge Network of soil/water physicochemical & biological properties (soil/water concepts), derived from ASTM Standard Methods (ASTMi,n) and relevant scientific/applicable references (published papers—PPi,n) to fill up/bridge the gap of the information science between cited Standards and infiltration discipline conceptual vocabulary providing accordingly a dedicated/internal Knowledge Base (KB). This attempt constitutes an innovative approach, since it is based on externalizing domain knowledge in the form of Ontology-Based Knowledge Networks, incorporating standardized methodology in soil engineering. The ontology soil/water concepts (semantics) of the developed network correspond to soil/water physicochemical & biological properties, classified in seven different generations that are distinguished/located in infiltration/percolation process of contaminated water through soil porous media. The interconnections with arcs between corresponding concepts/properties among the consecutive generations are defined by the relationship of dependent and independent variables. All these interconnections are documented according to the below three ways: 1) dependent and independent variables interconnected by using the logical operator “<em>depends on</em>” quoting existent explicit functions and equations;2) dependent and independent variables interconnected by using the logical operator “<em>depends on</em>” quoting produced implicit functions, according to Rayleigh’s method of indices;3) dependent and independent variables interconnected by using the logical operator “<em>related to</em>” based on a logical dependence among the examined nodes-concepts-variables. The aforementioned approach provides significant advantages to semantic web developers and web users by means of prompt knowledge navigation, tracking, retrieval and usage.
文摘The present study was designed to assess lead levels in playground soil and accumulated dust on playground equipment and then correlate those environmental lead measurements with children’s blood lead in the surrounding neighborhoods. Soil lead and surface dust were collected from 14 playgrounds in Muncie, Indiana, and blood lead levels were calculated for nearby children. Correlation analyses revealed a moderate positive association between dust Pb and soil Pb with a correlation coefficient r = 0.46 (p = 0.099). The relationship between settled dust on playground equipment and composite blood lead level also showed a medium positive correlation, indicated by r = 0.36 (p = 0.202). A positive correlation was also observed between soil Pb and composite blood lead values, as evidenced by r = 0.51 (p = 0.061). Furthermore, the assessment of spatial autocorrelation using Moran’s I index indicated no significant spatial clustering for the variables studied (dust Pb, soil Pb, and blood Pb). Correlation analysis showed a connection between lead levels in soil and dust, but no significant links were found between soil lead and blood lead and between dust lead and blood lead. These results suggest that environmental lead in parks has a limited impact on children’s blood lead levels nearby. Spatial autocorrelation analysis also revealed no significant spatial patterns among variables—dust, soil, and blood lead. Given these findings, it is recommended to seek expertise from qualified professionals and further perform comprehensive testing and analysis to investigate potential lead sources in children’s blood. The outcomes of this study offer valuable insights into assessing playground environmental lead contamination, contributing to future research priorities in this area. Specifically, future studies could focus on collecting larger sample sizes and characterizing blood lead in children who frequently use playgrounds rather than those who live nearby but may or may not use the playgrounds.
