含水量对酸性污染土电化学特性影响的试验研究

Effect of the moisture content on electrochemical properties of acidic contaminated soil

基于电化学阻抗谱在酸性污染土研究方面理论体系的不足,提出了运用电化学测试技术(EIS)来研究含水量对酸性污染土电化学特性影响的方法。通过对不同含水量下同一pH值的酸性污染土试样进行电化学测试和数据拟合,得出了Nyquist图、Bode图及等效电路参数。研究表明:含水量对Nyquist图的影响呈现为高频区曲线与阻抗实部的截距L随着含水量增大而减小,且高频区曲线圆弧直径D也随着含水量增大而减小;Bode图中阻抗模值在不同频率受含水量的影响呈规律性变化;含水量对酸性污染土的等效电路参数值的影响表现为溶液电阻、电荷传递电阻、扩散电阻的数值均随着酸性污染土含水量的上升而下降,而常相位角元件双电层电容参数值随着酸性污染土含水量的下降而上升。

Based on the deficiency of the theory system for electrochemical impedance spectroscopy（EIS） study in the aspect of acid contaminated soil,an EIS technique was proposed to study the influence of moisture content on electrochemical characteristics of the acid contaminated soil. Through the testing and fitting for electrochemical data of the acid contaminated soil samples with different moisture content,the Nyquist diagram,Bode diagram and equivalent circuit parameters were obtained. Results show that high frequency area,intercept L and arc diameter D of Nyquist diagram decrease with the increase of moisture content. In Bode diagram,the impedance modulus regularly changes with the change of moisture content under different frequencies. For the equivalent circuit parameters,the solution resistance,charge transfer resistance and diffusion resistance all decrease with the increasing moisture content. The parameter of constant phase angle element（the electric double layer capacitance） increases with the decrease of moisture content in the acid contaminated soil.