中文摘要：

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.

英文摘要：

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.