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电化学(中英文) ›› 2017, Vol. 23 ›› Issue (6): 702-707.  doi: 10.13208/j.electrochem.161129

• 研究论文 • 上一篇    下一篇

酸性溶液中Fe2+ /Fe3+相互转换对电极还原行为的影响

秦建新*,林 峰,刘文平,陈 超,任孟德   

  1. 中国有色桂林矿产地质研究院 广西超硬材料重点实验室,国家特种矿物材料工程技术研究中心,广西 桂林 541000
  • 收稿日期:2016-11-29 修回日期:2017-03-03 出版日期:2017-12-28 发布日期:2017-03-30
  • 通讯作者: 秦建新 E-mail:qdqinjianxin@163.com
  • 基金资助:

    广西科技计划基地和人才专项(重点实验室建设项目, No.16-380-35):资助

Effect of Fe2+/Fe3+Interconvertion on Reduction Behavior of Fe3+ in Acidic Electrolytes

QIN Jian-xin*, LIN Feng, LIU Wen-ping, CHEN Chao, REN Meng-de   

  1. Guangxi Key Laboratory of super-hard material, National Special Mineral Materials Engineering Technology Research Center, China Nonferrous Metals (Guilin) Geology and Mining Co., Ltd. Guilin 541004, China
  • Received:2016-11-29 Revised:2017-03-03 Published:2017-12-28 Online:2017-03-30
  • Contact: QIN Jianxin E-mail:qdqinjianxin@163.com

摘要:

采用线性扫描伏安法和循环伏安法研究了含有Cl-、SO42-的酸性溶液中Fe2+/Fe3+相互转换对电极反应和Fe3+还原过程的影响. 结果表明: [Fe]T=1 mol·L-1条件下,溶液中Fe3+/Fe2+的还原析出过程经过两个阶段:(1) E=0.35 V左右Fe3+还原成Fe2+过程; (2) E=-0.3 V之后H+的还原同时Fe2+离子与OH-相结合生产Fe(OH)2;  Fe3+/Fe2+的相互转化主要影响Fe3+的第一还原阶段的还原峰电流和峰电位. |ipa/ipc|值随c(Fe3+ )/c(Fe2+ )增大而增大,且扫描速度慢时影响大,扫描速度快时影响小; 0.50 mol·L-1 Fe2++0.50 mol·L-1 Fe3+时,随扫描速率的变化|ipa/ipc|值变化最小(|ipa/ipc|≈1.20). 同时,c(Fe3+ )/c(Fe2+ )也影响平衡电位,平衡电位随c(Fe3+ )/c(Fe2+ )增大而正移,电位从E1=0.501 V升至E5=0.565 V.

关键词: Fe2+/Fe3+相互转换, 循环伏安, 极化曲线, 还原行为

Abstract: The influences of ferrous/ferric (Fe2+/Fe3+) interconvertion on electrochemical reduction and electrode reaction of Fe3+ were investigated by using linear sweep voltammetry, potentiostatic method and cyclic voltammetry (CV) in acidic electrolytes containing chloride ion (Cl- ) and sulfate ion (SO42-). It was shown that the reduction process of Fe3+/Fe2+ would take place in two independent stages: (1) the reduction of Fe3+ to Fe2+ at E=0.35V and (2) the co-precipitation of Fe2+ by forming Fe(OH)2 (E≤-0.3 V) instead of Fe. The major effect of Fe2+/Fe3+ interconvertion on the reduction is the |ipa/ipc| of quasi-reversible and equilibrium potential in the first stage. Practically speaking, the |ipa/ipc| values increased with the increase of c(Fe3+ )/c(Fe2+ ), and the values of |ipa/ipc| at fast sweep rates were less strongly affected than those at slow sweep rates. The least variation in |ipa/ipc| (|ipa/ipc|≈1.20) with sweep rate was observed in 0.50 mol·L-1 Fe2+ and 0.50 mol·L-1  Fe3+ solutions. Meanwhile, the equilibrium potential was also affected by c(Fe3+ )/c(Fe2+ ). The equilibrium potential shifted more positively from E1=0.501 V in No. ① to E5=0.565 V in No. ⑤ among the five samples studied in this work.

Key words: Fe2+/Fe3+ interconvertion, cyclic voltammetry, polarization curve, reduction behavior

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