title: Mechanisms of competitive adsorption of Pb, Cu, and Cd on peat.
abstract: Combined use of batch equilibration adsorption and X-ray absorption spectroscopy (XAS) was employed to study the mechanisms of competitive adsorption of Pb, Cu, and Cd on Danish and Heilongjiang peat in single- and multi-solute systems. The adsorption capacity and initial adsorption rate on the same peat in single-solute systems followed the order Pb>Cu>Cd. Both the adsorbed amount of each metal (q'm) and its initial adsorption rate were decreased in multi-solute systems. It was observed that the adsorbed amounts of metals at low-energy adsorption sites (qm,1) decreased pronouncedly compared to those at high-energy adsorption sites (qm,2), indicating that the competitive adsorption of Pb, Cu and Cd occurred mainly at the low-energy adsorption sites. XAS study revealed that both Pb and Cu were coordinated in peat predominantly to carboxylic moieties without excluding the hydroxyl groups, thereby providing an insight into the mechanism of competitive adsorption of Pb and Cu on peat.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Qin
authors.forename: Bei
authors.initials: B
authors.lastname: Wen
authors.forename: Xiao-Quan
authors.initials: XQ
authors.lastname: Shan
authors.forename: Ya-Ning
authors.initials: YN
authors.lastname: Xie
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: Shu-Zhen
authors.initials: SZ
authors.lastname: Zhang
authors.forename: Shahamat U
authors.initials: SU
authors.lastname: Khan
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000032:analysis / Q000493:pharmacokinetics; D003300:Copper / Q000032:analysis / Q000493:pharmacokinetics; D007854:Lead / Q000032:analysis / Q000493:pharmacokinetics; D019216:Metals, Heavy / Q000032:analysis / Q000493:pharmacokinetics*; D012987:Soil; D013057:Spectrum Analysis / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000493:pharmacokinetics*; D018508:Water Purification / Q000379:methods*
chemical_list: D019216:Metals, Heavy; D012987:Soil; D014874:Water Pollutants, Chemical; D002104:Cadmium; D007854:Lead; D003300:Copper