水质稳定剂对模拟工业电解锌回水中电化学行为的影响

Effect of stabilizing agents for water quality on electrochemical behavior in simulated industrial electrolytic zinc reused water

采用动电位扫描、Tafel极化以及交流阻抗等电化学测试技术研究工业电解锌净化水回用系统中3种水质稳定剂(YJ101,YJ102．YJ103)对锌电解过程的影响。对0．5 mol／L ZnSO4溶液中动电位扫描的研究结果表明,水质稳定剂可以明显增大电解锌过程的阴极极化,在温度为25℃,极化电流密度为4 A／dm2时,电解锌的阴极极化至少增加0．030 V,其中YJ103最大增加0．106 V;在温度为40℃,极化电流密度为4 A／dm2时,电解锌的阴极极化至少增加0．051 V,其中YJ103最大增加0．101 V。Tafel极化结果表明,水质稳定剂的加入使得锌阴极还原反应的Tafel斜率平均增大约25 mV。交流阻抗测量结果表明,水质稳定剂能够增加锌离子还原的阴极极化阻力。水质稳定剂都能细化沉积锌层的晶粒,平滑锌沉积层。在0．5 mol/L Na2SO4溶液中的阴极极化结果进一步表明水质稳定剂在一定条件下能抑制氢的析出,提高锌电解过程的电流效率。

The effects of three stabilizing agents （YJ 101, YJ 102, YJ 103） for water quality on the zinc electrolysis process in industrial electrolytic zinc purified water reused system were investigated by linear sweep voltammetry, Tafel plot and alternating current（AC） impedance. The results show that three stabilizing agents for water quality can all increase cathode polarization of zinc electrolysis process from the results of linear sweep voltammetry in 0.5 mol/L ZnSO4 solution. At 4 A/dm^2 polarization current, the potential of cathode polarization moves negatively 0.030 V or 0.051 V at least at 25 ℃ or 40 ℃. Moreover, the Tafel slope （be） of zinc reduction process rises by about 25 mV due to the addition of stabilizing agents for water quality. Scanning electron micrographs show that three stabilizing agents for water quality can fine crystal grains. And the results of linear sweep voltammetry in 0.5 mol/L Na2SO4 solution shows further that three stabilizing agents for water quality can inhibit hydrogen evolution under specific experimental conditions, and improve current efficiency.