物理化学学报 >> 2010, Vol. 26 >> Issue (02): 265-269.doi: 10.3866/PKU.WHXB20100206

热力学、热化学和溶液化学 上一篇    下一篇

浓度及冷冻鄄解冻处理对CuCl2水溶液中Cu2+区域结构的影响

王文华, 赵林, 阎波, 谭欣, 贺博, 潘志云   

  1. 天津大学环境科学与工程学院, 天津 300072; 中国科学技术大学国家同步辐射实验室, 合肥 230029
  • 收稿日期:2009-09-21 修回日期:2009-11-09 发布日期:2010-01-26
  • 通讯作者: 赵林 E-mail:zhaolin@tju.edu.cn

Effects of Concentration and Freeze-Thaw Treatment on the Local Structure of Cu2+ in CuCl2 Aqueous Solutions

WANG Wen-Hua, ZHAO Lin, YAN Bo, TAN Xin, HE Bo, PAN Zhi-Yun   

  1. School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, P. R. China; National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
  • Received:2009-09-21 Revised:2009-11-09 Published:2010-01-26
  • Contact: ZHAO Lin E-mail:zhaolin@tju.edu.cn

摘要:

应用扩展X射线吸收精细结构(EXAFS)光谱研究了CuCl2水溶液中Cu2+的区域环境结构, 通过测定CuCl2水溶液在不同浓度条件下及冷冻-解冻(FT)处理前后Cu K边EXAFS 吸收谱, 研究了浓度及冷冻-解冻处理对Cu2+第一配位层结构的影响. EXAFS实验结果表明, CuCl2水溶液中Cu2+第一配位层距离中心原子Cu最近邻原子为O原子, 配位数介于3.0-4.3之间, Cu—O键长在0.192-0.198 nm 之间, 这种结构与Cu2+的Jahn-Teller效应有关. 不同浓度的CuCl2水溶液中Cu2+的区域环境结构有很大不同, 随着CuCl2水溶液浓度的升高, Cu2+第一配位层配位数减小, Cu—O键伸长. 结构参数拟合结果证实冷冻-解冻处理对Cu2+的区域环境结构有影响, CuCl2溶液经冷冻-解冻处理后, Cu2+第一配位层配位数变大, 热无序度增加.

关键词: EXAFS, CuCl2水溶液, 水合离子结构, 配位数, 浓度, 冷冻-解冻处理

Abstract:

The microscopic local environmental structure of Cu2+ ions in copper chloride solutions was investigated by X-ray absorption fine structure (EXAFS) spectroscopy. The effects of salt concentration and freeze-thaw (FT) treatment on the first coordination shell of Cu2+ were analyzed by examining the Cu K edge EXAFS spectra of CuCl2 aqueous solutions before and after FT treatment at various concentrations. The EXAFS results show that Cu2+ has 3.0-4.3 oxygen nearest neighbors with Cu—O bond length of 0.192 -0.198 nm in the first coordination shell. These structural properties can be ascribed to the Jahn-Teller effect. We found differences in the microscopic local structure of Cu2+ for various concentrations in CuCl2 aqueous solutions.With an increase in the salt concentration, the coordination number of Cu2+ decreases and the Cu—O bond length increases in the first coordination shell. The influence of FT treatment on the microscopic local environmental structure of Cu2+ was determined fromthe fitting results of the structural parameters. The coordination number of Cu2+ in its first coordination shell and the degree of thermal disorder increase when the FT treatment is operated in CuCl2 aqueous solutions.

Key words: EXAFS, CuCl2 aqueous solution, Structure of hydrated ion, Coordination number, Concentration, Freeze-thaw treatment

MSC2000: 

  • O645