Mechanism and microstructure of Eu(Ⅲ) interaction with γ-MnOOH by a combination of batch and high resolution EXAFS investigation  

作　　者：GAO Xing SHENG GuoDong HUANG YuYing 

机构地区：[1]Shanghai Synchrotron Radiation Facility (SSRF),Shanghai Institute of Applied Physics,Chinese Academy of Sciences [2]School of Chemistry and Chemical Engineering,Shaoxing University

出　　处：《Science China Chemistry》2013年第11期1658-1666,共9页中国科学（化学英文版）

基　　金：Financial supports from the National Natural Science Foundation of China(11175244;21207092);the project of Chinese Academy of Sciences(KJCX2-YW-N43);973 projects(2011CB933700)are acknowledged

摘　　要：In this paper, the macroscopic interaction method and high resolution EXAFS technique with a bent crystal analyzer were combined to study Eu（III） interaction mechanism and microstructure with y-MnOOH as a function of pH. The results indicated that Eu（III） interaction with y-MnOOH was apparently dependent on pH but independent of ionic strength, suggesting the for- mation of inner-sphere surface complexation for Eu（III） onto y-MnOOH. Results of EXAFS analysis indicated that Eu was surrounded by -9.00 atoms in first coordination shell at REu-O =2.40A, and second shell of Mn atoms at REu-Mn ≈ 3.60 was observed for the three adsorption samples. These findings suggested formation of a bidentate surface complex with Eu（III） bonding by edge sharing to MnO6-octahedron on y-MnOOH surface. Both the macroscopic interaction data and the molecular level evidence of Eu（III） microstructure at the 3,-MnOOH-water interface should be factored into better understanding the fate and mobility of Eu（III） and related radionuclides in the natural soil and water environment.In this paper,the macroscopic interaction method and high resolution EXAFS technique with a bent crystal analyzer were combined to study Eu(Ⅲ)interaction mechanism and microstructure withγ-MnOOH as a function of pH.The results indicated that Eu(Ⅲ)interaction withγ-MnOOH was apparently dependent on pH but independent of ionic strength,suggesting the formation of inner-sphere surface complexation for Eu(Ⅲ)ontoγ-MnOOH.Results of EXAFS analysis indicated that Eu was surrounded by^9.0 O atoms in first coordination shell at REu–O≈2.40,and second shell of Mn atoms at REu–Mn≈3.60 was observed for the three adsorption samples.These findings suggested formation of a bidentate surface complex with Eu(Ⅲ)bonding by edge sharing to MnO6-octahedron on γ-MnOOH surface.Both the macroscopic interaction data and the molecular level evidence of Eu(Ⅲ)microstructure at the γ-MnOOH-water interface should be factored into better understanding the fate and mobility of Eu(Ⅲ)and related radionuclides in the natural soil and water environment.

关 键 词：high resolution EXAFS technique bent crystal analyzer Eu（III） y-MnOOH interaction mechanism MICROSTRUCTURE 

分 类 号：O621.25[理学—有机化学]