钠盐溶液中U(Ⅵ)的电化学电子转移与晶化研究  

Electrochemical Electron Transfer and Crystallization Process of Uranium( Ⅵ) in Sodium Salt Solution

作　　者：宗美荣 何辉超[2] 董发勤[1,2] 何平[2] 孙仕勇[1] 刘明学[1] 聂小琴[1] 

机构地区：[1]西南科技大学固体废物处理与资源化教育部重点实验室,绵阳621010 [2]西南科技大学四川省非金属复合与功能材料重点实验室-省部共建国家重点实验室培育基地,绵阳621010

出　　处：《高等学校化学学报》2016年第9期1701-1709,共9页Chemical Journal of Chinese Universities

基　　金：国家"九七三"计划项目(批准号:2014CB846003);国家自然科学基金(批准号:41272371);中国博士后科学基金第59批面上基金(编号:2016M592698)资助~~

摘　　要：采用循环伏安法分析钠盐溶液中U(Ⅵ)的电化学行为,恒电位电化学还原处理U(Ⅵ),利用交流阻抗谱分析电化学还原反应中的过程动力学特性,利用X射线衍射、扫描电子显微镜和电子能谱等方法分析了U(Ⅵ)的电化学晶化.结果表明,在钠盐溶液中,U(Ⅵ)可通过电化学反应先还原成低价的U(V)并进一步还原为U(Ⅳ),U(Ⅳ)一步氧化为U(Ⅵ),U(Ⅳ)/U(Ⅵ)之间的电化学转化过程受扩散控制,且U(Ⅵ)的电化学电子转移易受环境p H值的影响;恒电位还原4 h时,溶液中U(Ⅵ)的去除率可达90%,U(Ⅵ)的结晶固化产物主要以固态的(UO2)6O2(OH)8·6H2O(水铀矿)和UO2的形式附着在工作电极上.Electrochemical beheaviors of uranium（ VI） was investigated with cyclic voltammetry and chronoamperometry（ CV）. The reduction of U（ Ⅵ） was analyzed by potentiostatic electrochemical and the kinetics was investigated with electrochemical impedance spectroscopy（ EIS）. In addition,crystallization of U（ Ⅵ）were analyzed by X-ray diffraction（ XRD）,scanning electron microscopy（ SEM） and energy-dispersive spectrometry（ EDS）. The results indicated that the reduction processes of U（ Ⅵ） to U（ Ⅳ） was significantly in fluenced by the p H value of solution,with the p H value changed from 3. 87 to 4. 50,the cyclic voltammetry showed that the reduction of U（ Ⅵ） to U（ Ⅳ） was in a manner of two-step one-electron process with a diffusion-controlled reaction mechanism. The cyclic voltammetry results presented a constant potential reduction method for removing U（ Ⅵ） from aqueous solution,and the reduction efficiency can reach 90%. At a constant potential,U（ Ⅵ） mainly crystalized into solid phases in the forms of UO2and（ UO2）6O2（ OH）8·6H2O. These results could provide a basis for removing and collecting U（ Ⅵ） from solution.

关 键 词：铀(Ⅵ) 电化学 电化学阻抗谱 结晶 

分 类 号：O646[理学—物理化学]