title: Evaluation of soil washing process with carboxymethyl-β-cyclodextrin and carboxymethyl chitosan for recovery of PAHs/heavy metals/fluorine from metallurgic plant site.
abstract: 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 using 50 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.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: yemao@issas.ac.cn.
authors.forename: Mao
authors.initials: M
authors.lastname: Ye
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: sunmingming@njau.edu.cn.
authors.forename: Mingming
authors.initials: M
authors.lastname: Sun
authors.affiliation: Department of Chemistry, Maseno University, Private Bag, Maseno 40105, Kenya.
authors.forename: Fredrick Orori
authors.initials: FO
authors.lastname: Kengara
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Jingting
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Ni
authors.initials: N
authors.lastname: Ni
authors.affiliation: Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Xinglun
authors.initials: X
authors.lastname: Yang
authors.affiliation: Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Huixin
authors.initials: H
authors.lastname: Li
authors.affiliation: Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: jiangxin@issas.ac.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Jiang
mesh_terms: D048271:Chitosan / Q000031:analogs & derivatives* / Q000737:chemistry; D005461:Fluorine / Q000737:chemistry*; D008669:Metallurgy; D019216:Metals, Heavy / Q000737:chemistry*; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D011084:Polycyclic Aromatic Hydrocarbons; D012987:Soil; D012989:Soil Pollutants; D047392:beta-Cyclodextrins; C441457:carboxymethyl-beta-cyclodextrin; C514968:carboxymethyl-chitosan; D005461:Fluorine; D048271:Chitosan
keywords: Carboxymethyl chitosan; Carboxymethyl-β-cyclodextrin; Mixed-contaminated sites; Soil washing; Tenax extraction