Experimental study on electrokinetic removal efficiency of copper-lead- contaminated loess enhanced by novel hydrogel electrodes and its inherent mechanism

In this study, a novel hydrogel electrode is used to investigate the migration law of copper (Cu) and lead (Pb) in artificially prepared Cu- and Pb-contaminated loess. The novel hydrogel electrode is compared with the geosynthetic material electrode (EKG) in electrokinetic (EK) remediation. The evolution law of EK remediation parameters is analyzed by using a novel hydrogel electrode combined with different strengthening methods, and the influences of different strengthening methods on the removal efficiency of heavy metal ions and the internal mechanism are revealed. The results show that acid pretreatment combined with autonomous pH regulation of the cathode can significantly reduce the focusing phenomenon surrounding the cathode, facilitating the electromigration of cations and anions and enhancing the removal efficiency. It proves the proposed method's feasibility and effectiveness of the Cu and Pb removals. The combination of the exchange electrode and point acid can significantly reduce the accumulation of ions near the cathode. The novel hydrogel electrode has excellent performance in terms of the minimal electrochemical polarization, low resistance and high conductivity based on its microscopic analysis. Therefore, a novel hydrogel electrode combined with the strengthening methods is proposed to improve the removal efficiency and solve the electrochemical polarization and focusing effects in the EK process.