镉污染粉土电化学特性试验研究

基于电化学测试技术,将电化学阻抗谱(EIS)理论与测试技术应用于镉污染粉土内部结构和电化学特性的研究。通过试验得出镉污染粉土的Nyquist图表现为一个时间常数的容抗弧,Bode图中阻抗模值受污染介质含量和频率的影响;模拟分析得到镉污染粉土的等效电路模型,主要包括溶液电阻、固液界面电阻和固体颗粒表面双电层电容三个主要电学元件;通过拟合等效电路参数值后得出:溶液电阻随着污染介质含量的增大呈对数减小,固液界面电阻随着污染介质含量的增大呈线性减小;固体颗粒表面双电层电容随着污染介质含量的增大呈指数增大。

Experimental Study of Electrochemical Impedance Spectroscopy on Cadmium Contaminated Silt

Based on electrochemical techniques, the electrochemical impedance spectroscopy (EIS) theory and testing technology are applied to study the internal structure and electrochemical properties of cadmium contaminated silt. Through experiments, Nyquist diagram of cadmium contaminated silt showed a capacitive loop with a time constant, in Bode diagram, the impedance modulus is influenced by the content of contaminated medium and the frequency; after analyzing, the equivalent circuit model of cadmium contaminated silt is obtained, mainly including three main electrical components: solution resistance, solid-liquid interface resistance and electric double layer capacitance of solid particle surface; through analyzing the parameters of equivalent circuit: solution resistance decreases logarithmically with the increasing content of contamination; the solid-liquid interface resistance decreases linearly with the increasing content of contamination; the electric double layer capacitance follows an exponentially increasing with the increasing content of contamination.