Evaluation of soil washing process with carboxymethyl-β-cyclodextrin and carboxymethyl chitosan for recovery of PAHs/heavy metals/fluorine from metallurgic plant site  

作　　者：Mao Ye Mingming Sun Fredrick Orori Kengara Jingting Wang Ni Ni Li Wang Yang Song Xinglun Yang Huixin Li Feng Hu Xin Jiang 

机构地区：[1]State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences [2]Soil Ecology Lab,College of Resources and Environmental Sciences,Nanjing Agricultural University [3]Department of Chemistry,Maseno University,Private Bag,Maseno 40105,Kenya

出　　处：《Journal of Environmental Sciences》2014年第8期1661-1672,共12页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos.41030531,41001335G,21377138 and 41271464b)

摘　　要：Polycyclic aromatic hydrocarbons（PAHs）/heavy metals/fluorine（F） mixed-contaminated sites caused by abandoned metallurgic plants are receiving wide attention. To address the associated environmental problems,this study was initiated to investigate the feasibility of using carboxymethyl-β-cyclodextrin（CMCD） and carboxymethyl chitosan（CMC） solution to enhance ex situ soil washing for extracting mixed contaminants. Further,Tenax extraction method was combined with a first-three-compartment model to evaluate the environmental risk of residual PAHs in washed soil. In addition,the redistribution of heavy metals/F after decontamination was also estimated using a sequential extraction procedure. Three successive washing cycles using50 g/L CMCD and 5 g/L CMC solution were effective to remove 94.3% of total PAHs,93.2% of Pb,85.8% of Cd,93.4% of Cr,83.2% of Ni and 97.3% of F simultaneously. After the 3rd washing,the residual PAHs mainly existed as very slowly desorbing fractions,which were in the form of well-aged,well-sequestered compounds; while the remaining Pb,Cd,Cr,Ni and F mainly existed as Fe–Mn oxide and residual fractions,which were always present in stable mineral forms or bound to non-labile soil fractions. Therefore,this combined cleanup strategy proved to be effective and environmentally friendly.Polycyclic aromatic hydrocarbons（PAHs）/heavy metals/fluorine（F） mixed-contaminated sites caused by abandoned metallurgic plants are receiving wide attention. To address the associated environmental problems,this study was initiated to investigate the feasibility of using carboxymethyl-β-cyclodextrin（CMCD） and carboxymethyl chitosan（CMC） solution to enhance ex situ soil washing for extracting mixed contaminants. Further,Tenax extraction method was combined with a first-three-compartment model to evaluate the environmental risk of residual PAHs in washed soil. In addition,the redistribution of heavy metals/F after decontamination was also estimated using a sequential extraction procedure. Three successive washing cycles using50 g/L CMCD and 5 g/L CMC solution were effective to remove 94.3% of total PAHs,93.2% of Pb,85.8% of Cd,93.4% of Cr,83.2% of Ni and 97.3% of F simultaneously. After the 3rd washing,the residual PAHs mainly existed as very slowly desorbing fractions,which were in the form of well-aged,well-sequestered compounds; while the remaining Pb,Cd,Cr,Ni and F mainly existed as Fe–Mn oxide and residual fractions,which were always present in stable mineral forms or bound to non-labile soil fractions. Therefore,this combined cleanup strategy proved to be effective and environmentally friendly.

关 键 词：Mixed-contaminated sites Soil washing Carboxymethyl-β-cyclodextrin Carboxymethyl chitosan Tenax extraction 

分 类 号：X82[环境科学与工程—环境工程]