硝酸镉污染高岭土电化学特性试验研究

摘要

Based on electrochemical impedance spectrum test results of different cadmium nitrate content of kao -lin soil, and according to the Nyquist and Bode graphs the corresponding equivalent circuit parameters were simula -ted, The analysis results show that the pollution at 6 hour, with the increase of cadmium nitrate concentration , kao-lin Nyquist diagram mode presents from Randle to Non-Randle mode .Solution resistance of circuit parameters de-creases , phase angle of capacitance increase , the solid liquid interface resistance , and diffusion impedance de-crease 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 , diffu-sion 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 Cd 2+between kaolin particles and cadmium nitrate ioni-zation of pore solution .%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。