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用扩展X射线吸收精细结构光谱(EXAFS)研究了溶液中重金属Zn(Ⅱ)在不同pH条件下的微观结构。在酸性条件下(pH<7.0),锌离子以六配位八面体结构的水合离子存在,Zn-O原子平均间距为2.08A。随着pH升高,Zn(Ⅱ)的微观构型从六配位的八面体结构转变为四配位的四面体结构,Zn-O原子间距为1.96A。EXAFS结果从分子水平表明,Zn(Ⅱ)在不同pH下其存在形式和微观结构不一样。这些微观结构信息对研究不同pH环境下Zn在颗粒物—水界面和溶液中的反应有重要意义。
The microstructure of heavy metal Zn (Ⅱ) in solution under different pH conditions was studied by extended X - ray absorption fine structure spectroscopy (EXAFS). Under acidic conditions (pH <7.0), zinc ions exist as hydrated ions with hexacoordinated octahedral structure, and the average spacing of Zn-O atoms is 2.08A. With the increase of pH, the microstructure of Zn (Ⅱ) changed from hexahedral octahedron structure to tetrahedral tetrahedral structure. The spacing of Zn-O atoms was 1.96A. The results of EXAFS show that the molecular structure of Zn (Ⅱ) is different at different pH. These microstructural information is of great importance for studying the reaction of Zn at the particle-water interface and in solution under different pH conditions.