title: [X-ray absorption fine structure (XAFS) study of the effects of pH on Pb(II) sorption by soil].
abstract: Combined batch sorption and in situ X-ray absorption fine structure (XAFS) provide direct assessment of the mechanisms for Pb(II) sorption at the soil-water interface under different pH conditions. The XAFS data indicated that the innersphere Pb sorption complex with ionic character (Pb4 (OH)4(4+)) dominated the Pb surface speciation, and the outer-sphere Pb sorption complex and the precipitation of calcium carbonate containing Pb(PbCaCO3) were also involved in the adsorption samples. Coordination number and radial distance of the first-shell Pb-O decreased from 0.172 7 to 0.166 6 nm and the percentage of inner-sphere complexes increased when the initial pH changed from 6.0 to 8.5, indicating that the mechanism of Pb(II) sorption by the soil was pH-dependent.
authors.affiliation: First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China. hningjing@163.com
authors.forename: Ning-Jing
authors.initials: NJ
authors.lastname: Hu
authors.forename: Peng
authors.initials: P
authors.lastname: Huang
authors.forename: Yong-Ming
authors.initials: YM
authors.lastname: Luo
authors.forename: Tian-Dou
authors.initials: TD
authors.lastname: Hu
authors.forename: Ya-Ning
authors.initials: YN
authors.lastname: Xie
authors.forename: Zi-Yu
authors.initials: ZY
authors.lastname: Wu