Hu Ning-Jing, Huang Peng, Luo Yong-Ming, Hu Tian-Dou, Xie Ya-Ning, Wu Zi-Yu
First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2010 Dec;30(12):3425-9.
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.
结合批量吸附和原位X射线吸收精细结构（XAFS）技术，可以直接评估不同pH条件下土壤-水界面铅（II）吸附的机制。XAFS数据表明，具有离子特性的内层铅吸附络合物（Pb4(OH)4(4+)）主导了铅的表面形态，外层铅吸附络合物以及含铅碳酸钙（PbCaCO3）的沉淀也参与了吸附样品的形成。当初始pH从6.0变为8.5时，第一壳层Pb-O的配位数和径向距离从0.172 7纳米降至0.166 6纳米，内层络合物的百分比增加，这表明土壤对铅（II）的吸附机制依赖于pH值。
