Black carbon （BC） can strongly adsorb hydrophobic organic compounds （HOCs）. The HOC sorption to coated BC could be attenuated in soil and sediment compared with that of the parent BC. To study the potential causes...Black carbon （BC） can strongly adsorb hydrophobic organic compounds （HOCs）. The HOC sorption to coated BC could be attenuated in soil and sediment compared with that of the parent BC. To study the potential causes of the sorption attenuation, humic acid （HA） and BC were isolated. Phenanthrene （PHE） was selected as the representative of HOCs. BC was coated with the precipitated HA. The PHE sorption to the HA-coated BC was determined. The HA coatings on BC could result in the significant sorption attenuation of PHE to BC. The attenuation varied in different HA origin and was positively correlated to the aromaticity of HA. The attenuation could be explained by the direct competition between HA and PHE for the available sorption sites on BC and the reduction of the available sorption sites as a result of the pore blockage of BC caused by the HA coatings. Therefore, the HA coatings on BC was one potential cause of the attenuation of HOC sorption to BC in soil and sediment.展开更多
The objective of this study was to examine the effect of biosurfactant on the sorption of phenanthrene （PHE） onto the original or HzO2-treated black loamy soil （typic isohumisols） and red sandy soil （typic ferral...The objective of this study was to examine the effect of biosurfactant on the sorption of phenanthrene （PHE） onto the original or HzO2-treated black loamy soil （typic isohumisols） and red sandy soil （typic ferralisols）. The sorption isotherms were performed with the original and ＂soft＂ carbon-removed soils in the presence and absence of biosurfactant （200 mg/L）. The sorption and degradation of biosurfactant were investigated. The result showed that organic matter played an important role in PHE sorption onto the black loamy and red sandy soils, and the PHE sorption isotherms on the ＂soft＂ carbon-removed soils exhibited more nonlinearity than those on the original soils. The values of partition coefficient （Kd） on the original black loamy soil with or without 200 mg/L biosurfactant were 181.6 and 494.5 mL/g, respectively. Correspondingly, in the red sandy soil, Kd was 246.4 and 212.8 mL/g in the presence or absence of biosurfactant, respectively. The changes of Kd suggested that biosurfactant inhibited PHE sorption onto the black loamy soil, but facilitated PHE sorption onto the red sandy soil. The nonlinearity of PHE sorption isotherm was decreased in the presence of biosurfactant. Site specific sorption might occur during PHE sorption onto both the original and the ＂soft＂ carbon-removed soils in the presence of biosurfactant. It was noted that biosurfactant could also be sorbed onto soils. The maximal sorption capacity of the red sandy soil for biosurfactant was （76.9 ± 0.007） μg/g, which was 1.31 times that of black loamy soil. Biosurfactant was degraded quickly in the two selected soils, and 92% of biosurfactant were mineralized throughout the incubation experiment for 7 d. It implied that biosurfactant should be added frequently when the remediation of polycyclic aromatic hydrocarbon （PAH）-contaminated soils was conducted through PAH desorption approach facilitated by biosurfactant.展开更多
Sorption and desorption of phenanthrene （PHE） onto black carbon （BC） extracted from sediments were studied in the presence of three types of dissolved organic matter （DOM）, including L-phenylalanine （L-PH）, pe...Sorption and desorption of phenanthrene （PHE） onto black carbon （BC） extracted from sediments were studied in the presence of three types of dissolved organic matter （DOM）, including L-phenylalanine （L-PH）, peptone and citric acid. The nonlinearity of the sorption isotherms increased in the presence of DOM. The presence of L-PH reduced the sorption capacity and desorption hysteresis because of the solubilization of PHE in L-PH solution. Peptone at 50-500 mg/L also led to a decrease in sorption attributed to solubilization, although the sorbed peptone on the BC surface could slightly increase PHE sorption. Unlike L-PH and peptone, citric acid enhanced the sorption capacity and irreversibility of PHE on BC mainly due to the strong sorption of citric acid on the BC surface. Our results may help to understand the different impacts of DOM on the distribution and transport of PAH in the environment.展开更多
Black carbon(BC)in ten contaminated sediments from the Song-Liao watershed,NE China,was isolated upon treatments using a combustion method at 375℃,and the isolates’sorption isotherms for phenanthrene(Phen)were deter...Black carbon(BC)in ten contaminated sediments from the Song-Liao watershed,NE China,was isolated upon treatments using a combustion method at 375℃,and the isolates’sorption isotherms for phenanthrene(Phen)were determined.All sorption isotherms were nonlinear and fitted well by the Freundlich model.A negative relation was found between Freundlich sorption nonlinearity parameter(n values)and BC/total organic carbon(TOC)content of the original sediments(r^(2)=0.687,p<0.01),indicating the dominance of BC in Phen sorption nonlinearity.The BC isolates from this industrialized region had n values of 0.342 to 0.505 and logKFOC values of 6.02 to 6.42(μg·kg^(–1)·OC^(–1))/(μg·L^(–1))n for Phen.At a given Ce,the BC had higher Koc value than the original sediments,revealing a higher sorption capacity for BC.BC was responsible for 50.0%to 87.3%of the total sorption at Ce=0.05 Sw,clearly indicating the dominance of BC particles in overall sorption of Phen by sediments.展开更多
In order to investigate the contribution of various black carbon(BC)contents to nonlinearity of sorption and desorption isotherms for acetochlor on sediment,equilibrium sorption and desorption isotherms were determine...In order to investigate the contribution of various black carbon(BC)contents to nonlinearity of sorption and desorption isotherms for acetochlor on sediment,equilibrium sorption and desorption isotherms were determined to measure sorption and desorption of acetochlor in sediment amended with various amounts of BC.In this paper,two types of BC referred to as BC400 and BC500 were prepared at 400℃ and 500℃,respectively.Higher preparation temperature facilitated the formation of micropores on BC to enhance its sorption capacity.Increase of the BC content obviously increased the sorption amount and reduced the desorption amount for acetochlor.When the BC500 contents in total organic carbon(TOC)increased from 0 to 60%,Freundlich sorption coefficient(K_(f))increased from 4.07 to 35.74,and desorption hysteresis became gradually obvious.When the content of BC in TOC was lower than 23%,the sorption isotherm had a significant linear correlation(p=0.05).In case of desorption,a significant nonlinear change could be observed when the content of BC was up to 13%.Increase of BC content in the sediment would result in shifting the sorption-desorption isotherms from linearity to nonlinearity,which indicated that contribution of BC to nonlinear adsorption fraction became gradually remarkable.展开更多
The sorption of 17α-ethinyl estradiol （EE2）, bisphenol A （BPA）, and 4-n-nonylphenol （NP） in single systems and the sorption of EE2 with different initial aqueous concentrations of BPA or NP were examined using ...The sorption of 17α-ethinyl estradiol （EE2）, bisphenol A （BPA）, and 4-n-nonylphenol （NP） in single systems and the sorption of EE2 with different initial aqueous concentrations of BPA or NP were examined using three soils. Results showed that all sorption isotherms were nonlinear and fit the Freundlich model. The degree of nonlinearity was in the order BPA （0.537-0.686） 〉 EE2 （0.705-0.858） 〉 NP （0.875-0.0.951） in single systems. The isotherm linearity index of EE2 sorption calculated by the Freundlich model for Loam, Silt Loam and Silt increased from 0.758, 0.705 and 0.858, to 0.889, 0.910 and 0.969, respectively, when BPA concentration increased from 0 to 1000 μg/L, but the effect of NP was comparably minimal. Additionally, EE2 significantly suppressed the sorption of BPA, but insignificantly suppressed that of NE These findings can be attributed to the difference of sorption affinity of EE2, NP and BPA on the hard carbon （e.g., black carbon） of soil organic matter that dominated the sorption in the low equilibrium aqueous concentration range of endocrine-disrupting chemicals （EDCs）. Competitive sorption among EDCs presents new challenges for predicting the transport and fate of EDCs under the influence of co-solutes.展开更多
Black carbon(BC)is a promising sediment amendment,as proven by its considerable adsorption capacity for hydrophobic organic pollutants and accessibility,but its reliability when used for the removal of pollutants in n...Black carbon(BC)is a promising sediment amendment,as proven by its considerable adsorption capacity for hydrophobic organic pollutants and accessibility,but its reliability when used for the removal of pollutants in natural sediments still needs to be evaluated.For example,the ageing process,resulting in changing of surface physicochemical properties of BC,will decrease the adsorption capacity and performance of BC when applied to sediment pollution control.In this study,how the ageing process and BC proportion affect the adsorption capacity of BC-sediment systems was modelled and quantitatively investigated to predict their adsorption capacity under different ageing times and BC additions.The results showed that the ageing process decreased the adsorption capacity of both BC-sediment systems,due to the blockage of the non-linear adsorption sites of BC.The adsorption capacity of rice straw black carbon(RC)-sediment systems was higher than that of fly ash black carbon(FC)-sediment systems,indicating that RC is more efficient than FC for nonylphenol(NP)pollution control in sediment.The newly established model for the prediction of adsorption capacity fits the experimental data appropriately and yields acceptable predictions,especially when based on parameters from the Freundlich model.However,to fully reflect the influence of the ageing process on BC-sediment systems and make more precise predictions,it is recommended that future work considering more factors and conditions,such as modelling of the correlation between the adsorption capacity and the pore volume or specific surface area of BC,be applied to build an accurate and sound model.展开更多
Dissolved organic matter plays a critical role in affecting sorption properties of biochar for organic contaminants.In this study,dissolved humic acid(DHA)as a representative of dissolved organic matter and oak sawdus...Dissolved organic matter plays a critical role in affecting sorption properties of biochar for organic contaminants.In this study,dissolved humic acid(DHA)as a representative of dissolved organic matter and oak sawdust-derived biochar as a sorbent were prepared and characterized.Roles of DHA in sorption of benzotriazole(BTA),an emerging organic contaminant,to biochar in different electrolyte solutions were investigated.The results revealed the dual roles of DHA in BTA sorption to biochar.On the one hand,DHA can compete for sites and/or block pores available for BTA to inhibit the adsorption of BTA to biochar.On the other hand,the sorbed DHA on biochar can serve as additional partitioning phase to promote the partition of BTA.The finding was in accordance with the site energy distribution analysis of BTA sorption that the site energy of the highest occurring frequency in the DHA-BTA system was lower than that in the DHA-free system(3.41-10.4 versus 13.1-20.1 kJ mol^(−1)).The variation in apparent BTA sorption to biochar affected by DHA was thus a combination of changes in both its partition and adsorption properties.A modified Dual-mode model including the aqueous concentration of DHA was proposed to predict the effect of DHA on BTA sorption to biochar in different electrolyte solutions,which showed good prediction performance with most BTA sorption coefficient(K_(d),L g^(−1))deviations within 0.1 log unit.展开更多
基金Project supported by the Natural Science Foundation of Shandong Province (No.Y2003B04).
文摘Black carbon （BC） can strongly adsorb hydrophobic organic compounds （HOCs）. The HOC sorption to coated BC could be attenuated in soil and sediment compared with that of the parent BC. To study the potential causes of the sorption attenuation, humic acid （HA） and BC were isolated. Phenanthrene （PHE） was selected as the representative of HOCs. BC was coated with the precipitated HA. The PHE sorption to the HA-coated BC was determined. The HA coatings on BC could result in the significant sorption attenuation of PHE to BC. The attenuation varied in different HA origin and was positively correlated to the aromaticity of HA. The attenuation could be explained by the direct competition between HA and PHE for the available sorption sites on BC and the reduction of the available sorption sites as a result of the pore blockage of BC caused by the HA coatings. Therefore, the HA coatings on BC was one potential cause of the attenuation of HOC sorption to BC in soil and sediment.
基金supported by the National Hi-Tech Research and Development Program (863) of China (No2007AA061101)the National Natural Scientific Foun-dation of China (No 20377024)
文摘The objective of this study was to examine the effect of biosurfactant on the sorption of phenanthrene （PHE） onto the original or HzO2-treated black loamy soil （typic isohumisols） and red sandy soil （typic ferralisols）. The sorption isotherms were performed with the original and ＂soft＂ carbon-removed soils in the presence and absence of biosurfactant （200 mg/L）. The sorption and degradation of biosurfactant were investigated. The result showed that organic matter played an important role in PHE sorption onto the black loamy and red sandy soils, and the PHE sorption isotherms on the ＂soft＂ carbon-removed soils exhibited more nonlinearity than those on the original soils. The values of partition coefficient （Kd） on the original black loamy soil with or without 200 mg/L biosurfactant were 181.6 and 494.5 mL/g, respectively. Correspondingly, in the red sandy soil, Kd was 246.4 and 212.8 mL/g in the presence or absence of biosurfactant, respectively. The changes of Kd suggested that biosurfactant inhibited PHE sorption onto the black loamy soil, but facilitated PHE sorption onto the red sandy soil. The nonlinearity of PHE sorption isotherm was decreased in the presence of biosurfactant. Site specific sorption might occur during PHE sorption onto both the original and the ＂soft＂ carbon-removed soils in the presence of biosurfactant. It was noted that biosurfactant could also be sorbed onto soils. The maximal sorption capacity of the red sandy soil for biosurfactant was （76.9 ± 0.007） μg/g, which was 1.31 times that of black loamy soil. Biosurfactant was degraded quickly in the two selected soils, and 92% of biosurfactant were mineralized throughout the incubation experiment for 7 d. It implied that biosurfactant should be added frequently when the remediation of polycyclic aromatic hydrocarbon （PAH）-contaminated soils was conducted through PAH desorption approach facilitated by biosurfactant.
基金The study was supported by the National Science Foundation for Innovative Research Group(No.51121003)the Major Science and Technology Program for Water Pollution Control and Treatment(No.2012ZX07202002)the Open Foundation of State Key Joint Laboratory of Environment Simulation and Pollution Control(Beijing Normal University)(No.10K05ESPCN)
文摘Sorption and desorption of phenanthrene （PHE） onto black carbon （BC） extracted from sediments were studied in the presence of three types of dissolved organic matter （DOM）, including L-phenylalanine （L-PH）, peptone and citric acid. The nonlinearity of the sorption isotherms increased in the presence of DOM. The presence of L-PH reduced the sorption capacity and desorption hysteresis because of the solubilization of PHE in L-PH solution. Peptone at 50-500 mg/L also led to a decrease in sorption attributed to solubilization, although the sorbed peptone on the BC surface could slightly increase PHE sorption. Unlike L-PH and peptone, citric acid enhanced the sorption capacity and irreversibility of PHE on BC mainly due to the strong sorption of citric acid on the BC surface. Our results may help to understand the different impacts of DOM on the distribution and transport of PAH in the environment.
基金the National Basic Research Program of China(Grant No.2004CB418502)the National Natural Science Foundation of China(Grant No.20477003).
文摘Black carbon(BC)in ten contaminated sediments from the Song-Liao watershed,NE China,was isolated upon treatments using a combustion method at 375℃,and the isolates’sorption isotherms for phenanthrene(Phen)were determined.All sorption isotherms were nonlinear and fitted well by the Freundlich model.A negative relation was found between Freundlich sorption nonlinearity parameter(n values)and BC/total organic carbon(TOC)content of the original sediments(r^(2)=0.687,p<0.01),indicating the dominance of BC in Phen sorption nonlinearity.The BC isolates from this industrialized region had n values of 0.342 to 0.505 and logKFOC values of 6.02 to 6.42(μg·kg^(–1)·OC^(–1))/(μg·L^(–1))n for Phen.At a given Ce,the BC had higher Koc value than the original sediments,revealing a higher sorption capacity for BC.BC was responsible for 50.0%to 87.3%of the total sorption at Ce=0.05 Sw,clearly indicating the dominance of BC particles in overall sorption of Phen by sediments.
基金This study was financially supported by 0the National Basic Research Program of China(Grant No.2007CB407302).
文摘In order to investigate the contribution of various black carbon(BC)contents to nonlinearity of sorption and desorption isotherms for acetochlor on sediment,equilibrium sorption and desorption isotherms were determined to measure sorption and desorption of acetochlor in sediment amended with various amounts of BC.In this paper,two types of BC referred to as BC400 and BC500 were prepared at 400℃ and 500℃,respectively.Higher preparation temperature facilitated the formation of micropores on BC to enhance its sorption capacity.Increase of the BC content obviously increased the sorption amount and reduced the desorption amount for acetochlor.When the BC500 contents in total organic carbon(TOC)increased from 0 to 60%,Freundlich sorption coefficient(K_(f))increased from 4.07 to 35.74,and desorption hysteresis became gradually obvious.When the content of BC in TOC was lower than 23%,the sorption isotherm had a significant linear correlation(p=0.05).In case of desorption,a significant nonlinear change could be observed when the content of BC was up to 13%.Increase of BC content in the sediment would result in shifting the sorption-desorption isotherms from linearity to nonlinearity,which indicated that contribution of BC to nonlinear adsorption fraction became gradually remarkable.
基金supported by the Special Environmental Research Funds for Public Welfare (No. 201209053)the National High Technology Research and Development Program (863) of China (No. 2008AA062502)
文摘The sorption of 17α-ethinyl estradiol （EE2）, bisphenol A （BPA）, and 4-n-nonylphenol （NP） in single systems and the sorption of EE2 with different initial aqueous concentrations of BPA or NP were examined using three soils. Results showed that all sorption isotherms were nonlinear and fit the Freundlich model. The degree of nonlinearity was in the order BPA （0.537-0.686） 〉 EE2 （0.705-0.858） 〉 NP （0.875-0.0.951） in single systems. The isotherm linearity index of EE2 sorption calculated by the Freundlich model for Loam, Silt Loam and Silt increased from 0.758, 0.705 and 0.858, to 0.889, 0.910 and 0.969, respectively, when BPA concentration increased from 0 to 1000 μg/L, but the effect of NP was comparably minimal. Additionally, EE2 significantly suppressed the sorption of BPA, but insignificantly suppressed that of NE These findings can be attributed to the difference of sorption affinity of EE2, NP and BPA on the hard carbon （e.g., black carbon） of soil organic matter that dominated the sorption in the low equilibrium aqueous concentration range of endocrine-disrupting chemicals （EDCs）. Competitive sorption among EDCs presents new challenges for predicting the transport and fate of EDCs under the influence of co-solutes.
基金supported by the Natural Science Foundation for Youths of Jiangsu Province of China(Nos.BK20190568 and BK20160945)the Key Laboratory of Water Pollution Control and Environmental Safety of Zhejiang Province(No.2018ZJSHKF02)+4 种基金the Basic Research Business Expenses Special Project of China Pharmaceutical University(No.2632018PY01)the Student Innovation Project of China Pharmaceutical Universitythe National Natural Science Foundation for Youths of China(No.21607078)the National Natural Science Foundation of China(No.41877463)Natural Science Foundation of Zhejiang Province(No.LZ19D030001)。
文摘Black carbon(BC)is a promising sediment amendment,as proven by its considerable adsorption capacity for hydrophobic organic pollutants and accessibility,but its reliability when used for the removal of pollutants in natural sediments still needs to be evaluated.For example,the ageing process,resulting in changing of surface physicochemical properties of BC,will decrease the adsorption capacity and performance of BC when applied to sediment pollution control.In this study,how the ageing process and BC proportion affect the adsorption capacity of BC-sediment systems was modelled and quantitatively investigated to predict their adsorption capacity under different ageing times and BC additions.The results showed that the ageing process decreased the adsorption capacity of both BC-sediment systems,due to the blockage of the non-linear adsorption sites of BC.The adsorption capacity of rice straw black carbon(RC)-sediment systems was higher than that of fly ash black carbon(FC)-sediment systems,indicating that RC is more efficient than FC for nonylphenol(NP)pollution control in sediment.The newly established model for the prediction of adsorption capacity fits the experimental data appropriately and yields acceptable predictions,especially when based on parameters from the Freundlich model.However,to fully reflect the influence of the ageing process on BC-sediment systems and make more precise predictions,it is recommended that future work considering more factors and conditions,such as modelling of the correlation between the adsorption capacity and the pore volume or specific surface area of BC,be applied to build an accurate and sound model.
基金the National Natural Science Foundation of China(41172223 and 41902259)the Natural Science Foundation of Hebei Province of China(D2020504006).
文摘Dissolved organic matter plays a critical role in affecting sorption properties of biochar for organic contaminants.In this study,dissolved humic acid(DHA)as a representative of dissolved organic matter and oak sawdust-derived biochar as a sorbent were prepared and characterized.Roles of DHA in sorption of benzotriazole(BTA),an emerging organic contaminant,to biochar in different electrolyte solutions were investigated.The results revealed the dual roles of DHA in BTA sorption to biochar.On the one hand,DHA can compete for sites and/or block pores available for BTA to inhibit the adsorption of BTA to biochar.On the other hand,the sorbed DHA on biochar can serve as additional partitioning phase to promote the partition of BTA.The finding was in accordance with the site energy distribution analysis of BTA sorption that the site energy of the highest occurring frequency in the DHA-BTA system was lower than that in the DHA-free system(3.41-10.4 versus 13.1-20.1 kJ mol^(−1)).The variation in apparent BTA sorption to biochar affected by DHA was thus a combination of changes in both its partition and adsorption properties.A modified Dual-mode model including the aqueous concentration of DHA was proposed to predict the effect of DHA on BTA sorption to biochar in different electrolyte solutions,which showed good prediction performance with most BTA sorption coefficient(K_(d),L g^(−1))deviations within 0.1 log unit.
