用EXAFS研究pH对水溶液中Zn(Ⅱ)微观结构的影响  

EXAFS study influence of pH on microscopic structure of zinc

作　　者：李贤良[1] 潘纲[1] 朱孟强[1] 陈灏[1] 胡天斗[2] 吴白玉[2] 谢亚宁[2] 杜永华[2] 

机构地区：[1]中国科学院生态环境研究中心环境水化学国家重点实验室 [2]中国科学院高能物理研究所同步辐射室,北京100049

出　　处：《核技术》2004年第12期895-898,共4页Nuclear Techniques

基　　金：中科院"百人"计划;国家自然科学基金(批准号:20073060)

摘　　要：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。Microscopic local structures of Zn(Ⅱ) were studied using extended X-ray absorption fine structure (EXAFS) spectroscopy under different pH conditions. When pH<7.0, Zn^(2+)(aq) was coordinated with six water molecules and the average Zn-O distance was measured to be 2.08A, which indicated that hydrated Zn^(2+)(aq) ions were in octahedral geometry under acid conditions. Under alkaline conditions, Zn^(2+)(aq) was coordinated with four water molecules and the average Zn-O distance was measured to be 1.96A, which indicated that hydrated Zn^(2+)(aq) ions were in tetrahedral geometry. EXAFS results provided detailed information on the form and microscopic structure of hydrated Zn(Ⅱ) ions under different pH conditions, which were fundamental for understanding the reactivity of Zn(Ⅱ) in solutions and at particle-water interfaces.

关 键 词：扩展X射线吸收精细结构光谱 ZN 微观结构 PH 吸附 

分 类 号：O647.31[理学—物理化学]