高等学校化学学报

高等学校化学学报 ›› 1989, Vol. 10 ›› Issue (5): 551.

• 研究简报 • 上一篇    下一篇

铬(Ⅲ)离子的阴极还原过程研究

江琳才1, 简素碧2   

  1. 1. 华南师范大学化学系;
    2. 华南理工大学化学系
  • 收稿日期:1987-09-03 出版日期:1989-05-24 发布日期:1989-05-24
  • 通讯作者: 江琳才

A Study on the Process of Cathodic Reduction of Chromium (Ⅲ) Ions

Jiang Lincai1, Jian Subi2   

  1. 1. Department of Chemistry, South China Normal University, Guangzhou;
    2. Department of Chemistry, South China Technological College, Guangzhou
  • Received:1987-09-03 Online:1989-05-24 Published:1989-05-24

PDF (PC)

被引次数

38

摘要： 铬(Ⅲ)离子在水溶液中以稳定的d2sp3型配位铬离子的形式存在,氧化和还原惰性都高,配体阴离子对其阴极还原行为的影响明显,曾引起不少研究者的兴趣[1～4]。当前由于人们对环保问题的注意,对三价铬电镀已引起重视并开展一定的研究。此种镀液多为硫酸盐、氯化物和硫氰酸盐等溶液,故用现代电化学方法对三价铬离子在这类溶液中的阴极还原行为进行研究是有意义的。

关键词: 铬(Ⅱ)离子, 阴极还原, 电位扫描法, 记时电量法, 旋转环盘电极

Abstract: The reductions of Chromium (Ⅲ) ions at HMDEhave been studied in the solutions of Na2SO4,NaCl and NaCNS. It is shown that the irreversibi-lity of the reaction varies with the nature of ligand anions. The irreversibility of the reaction in the solution of Na2SO4 is the most obvious while the presence of Cl- and CNS- reduces it and makes the reaction much faster and the difference of peak potential much smaller as well. It is confirmed by RRDEexperiments that the species formed at the first wave of the reduction of Cr3+ are Cr2+ ions which can be reduced to metal chromium at more negative potential. Thus, the process can be written asCr3+ +e=Cr2+, Cr2+ +2e=Cr The standard rate constant determined by using chronocoulometric method for the reduction reaction of Cr3+ ions in the solutions of 0.5 mol/L NaCl at HMDEis 3.0 × 10-5 cm·s-1 and the diffusion coefficient of Cr3+ ions in the same solution is 2.7×10-6 cm2 s-1.

Key words: Chromiun (Ⅲ) ions, Cathodic reduction, Potential sweep methods, Chronocoulometric methods, Rotating ring disc electrode

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