硝酸镉污染高岭土电化学特性试验研究

通过对不同含量硝酸镉的高岭土进行电化学阻抗谱进行测试,结合其Nyquist和Bode图谱模拟出相应的等效电路参数。分析结果表明,在污染6 h时,随着硝酸镉浓度增加,高岭土Nyquist图中呈现出由准Randle向非Randle变化,溶液电阻减小、常相位角元件电容增大、以及扩散阻抗逐渐减小至消失;在污染24 h时,高岭土Nyquist图中呈现出两个时间参数,电化学参数溶液电阻、常相位角元件、固液界面电阻、扩散阻抗均有所改变;随着时间的推移,高岭土与孔隙溶液硝酸镉电离出的Cd2+产生较强的电化学作用,高岭土体系密实度增大吸附性增强。

Experimental study on the electrochemical characteristics of kaolin polluted by cadmium nitrate

Based on electrochemical impedance spectrum test results of different cadmium nitrate content of kaolin soil, and according to the Nyquist and Bode graphs to simulate the corresponding equivalent circuit parameters, the analysis results show that the pollution at 6 hour, with the increase of cadmium nitrate concentration, kaolin Nyquist diagram mode presents from Randle to Non-Randle mode. Solution resistance of circuit parameters decreases, phase angle of capacitance increase, the solid liquid interface resistance, and diffusion impedance decrease gradually to disappear. When pollution at 24 hour, kaolin Nyquist diagram shows two time parameters, the electrochemical parameters of solution resistance, angle of phase capacitor, solid-liquid interface resistance, diffusion impedance changes as same as those at 6 hour. With the time increasing, kaolin system compactness increases with effect action of adsorption due to electrochemical effect Cd2+ between kaolin particles and cadmium nitrate ionization of pore solution.