赤泥基固化铜离子污染黄土状粉土的电化学阻抗谱特性分析OA

[Purposes]At present,the treatments of heavy metal contaminated sites are mostly based on mechanical and chemical property tests,thus proposing non-destructive,fast,convenient,and cost-effective physical evaluation methods is a key issue that needs to be solved urgently.[Meth-ods]In this paper,the curing effect of red mud-based curing agent on copper-contaminated loess was investigated,and the unconfined compressive strength and electrochemical impedance response of the cured body were systematically analyzed and evaluated,and the corresponding equivalent model was established for fitting.[Results]The results show that the unconfined compressive strength of the so-lidified body shows a trend of increasing and then decreasing with the increasing mass ratio of red mud fly ash,and the maximum strength value is achieved at the ratio of 13∶2.By analysing the image characteristics of Nyquist and Bode plots of electrochemical impedance spectra,the same can be con-cluded that the mass ratio of 13∶2 for red mud fly ash is the optimum mass ratio.In addition,the equivalent circuit of the solidified body electrochemical system is established as(QR)(Q(RW))R,and the relationships between the parametric components and the strength are analysed.The values of the equivalent circuit components Rs,Rct1,and Rct2 parameters are positively correlated with the strength,and the values of CPE1,CPE2,and W parameters are negatively correlated with the strength.The re-lationships between the pore solution resistance Rs,the ion transfer resistance Rct2 within the solidified body,and the strength and the mass ratio of red mud and fly ash(RM-FA)are established by parame-ter fitting,separtely,and the associated polynomials are obtained.The results of electrochemical im-pedance spectroscopy and the coincidences of parameters of each element of the equivalent circuit with traditional strength indices,indicating that the electrochemical impedance spectroscopy technique can be effectively used to evaluate the curing effect of copper-contaminated soils.