Application of Polypyrrole flexible electrode for electrokinetic remediation of Cr(VI)-contaminated soil in a main-auxiliary electrode system

摘要

A new electrokinetic remediation (EKR) system for remediation of hexavalent chromium (Cr(VI))-contaminated soil was explored in this study, which consists of main electrodes and unenergized auxiliary electrodes. Specifically, the graphite and Polypyrrole (PPy) were applied as main and auxiliary electrodes respectively, and the PPy used was chemically incorporated into linen fabric (LF). Five EKR experiments lasting 72 h were carried out in order to explore the Cr(VI) removal mechanism of the new EKR system. In the presence of PPy, the distribution of electric field along the ion migration direction and electric current were all improved and the Cr (VI) concentration around the auxiliary electrode was dropped. The changes of these parameters promoted the removal of Cr(VI) and the maximum removal efficiency of Cr(VI) in soil was 91.7%. It can be concluded that PPy auxiliary electrode coupled with EKR (PPy-EKR) had a positive effect on the removal of Cr(VI), which could not only accelerate the migration of Cr ions by affecting the distribution of electric field, but also contribute to adsorption and reduction of Cr(VI). Consequently, this research paved a road for the future application of mainauxiliary electrodes system for Cr(VI) removal in soil remediation.