室温氯化铜-氯化钠溶液中铜氯络合物浓度的电化学分析.pdf

11年12月
矿测试
December 2011
ROCK AND MINERAL ANALYSIS
732~736
文章编号:0254-5357(2011)06-0732-05
室温氯化铜一氯化钠溶液中铜氯络合物浓度的电化学分析
张艳清2,李和平,刘庆友,徐丽萍,张磊
1.中国科学院地球化学研究所,贵州贵阳550002;:2.中国科学院研究生院,北京100049
3.安徽省地质测绘技术院,安徽合肥230022)
摘要:运用Tal极化曲线和线性电势扫描法研究了常温弱酸性CuCl2-Na溶液中锎氟络合物体系的电化学放
电机理。通过测量不同浓度配比的CuCl2-Na溶液的极化曲线得到各自的交换电流密度,然后根据电化学反
应级数法计算直接在电极上放电的Cu(Ⅱ)-CI络合物的配位数。并且运用线性电势扫描法进一步研究了此络
合物在铂电极上的还原反应,在体系可逆的情况下计算得到其发生放电反应的离子浓度。结果表明:溶液中存在
的主要络离子是[Cu?l]t,在铂电极上发生电化学反应的铜络离子是 I CUCI]'。铜氯络离子在铂电极上的还原
反应分两步进行,其中第一步为可逆的单电子还原过程,体系中[CuCl和Cu的电化学反应级数均为一级
4.000mol/ L NACI-0.100mol/ L, CUCI2溶液体系中发生放电反应的[CuCl]的浓度为0.086mol/L.。研究结果为
目前学术界存在广泛分歧的Cu2在高浓度氟离子溶液中的放电机理提供了重要的实验依据,同时对未来湿法冶
金、地质和地球化学等领域中溶解态金属络合物的电化学分析具有一定的借鉴作用。
关键词:常温; Tafel曲线;伏安曲线;铜氯络合物;电化学
Electrochemical Analysis of the Concentration of Cupric Chloride Complex in
Cucl, -Nacl Solution at Room Temperature
ZHANG Yan-ging", 1 He-ping, LIU Qing-you,XU Li-ping, ZHANG Lei
1. Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
2. Graduate University of Chinese Academy of Sciences, Bejing 100049, China
3. Anhui Institute of Geological Surveying and Mapping, Hefei 230022, China)
Abstract The electrochemical reaction mechanism of Cui,Nacl weak acid solution was studied by the Tafel method
and linear potential sweep voltammetry at room tempcrature. The exchange current densities at different concentration
ratios of Cucl Nacl solution were obtained from their polarization curves and the coordination number of the
electrochemical reduction complex was calculated from electrochemical reaction order method. The electrochemical
reduction on Pt electrode was further studied by linear potential sweep voltammetry. Finally, the concentration of the
elecrochemical reduction complex ion was calculated when the procedure was reversed. The results were shown that
Cucl]"is the main cupric chloride complex in solution and the one for electrochemical reduction on Pt electrode. Two
one-electron reduction steps of the copper chloride complex were observed on the surface of the Pu electrode. The first
step was a one-electron-transfer reversible reduction process. The electrochemical reaction orders of Cucl"and u in
the system were both level one. In 4.000 mol/L Nacl + 0. 100) mol/l, Cucl, solution, the concentration of the
electrochemical reduction reactant( Cucl was 0.086 mol/L. The results provided important experimental
evidences for electrochemical reduction mechanism of Cu" in aqueous solutions with highly concentrated chloride ions
收稿日期:2010-12-06;接受日期:2011-03-22
基金项目:国家自然科学基金项目(40573046);中国科学院大型设备研制项目(YZ200720
作者简介:张艳清,博土研究生,主要从事电分析化学研究。E-mail: changyanqing@ mails. gig. ac.cen
通讯作者:李和平,研究员,从事实验地球化学的研究。E-mail:lihepingt@vip.skeg.cn
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