Experimental study on electrode materials characteristics for dewatering and remediation of copper-contaminated sediment from Tai Lake based on vacuum electro-osmosis

The vacuum electro-osmosis method enables integrated treatment of heavy metal-contaminated sediments by simultaneously removing water and pollutants. This study focuses on the dredged sediments from Tai Lake and investigates the performance of five electrode materials (electrokinetic geo-synthetics, graphite, aluminum, iron, and copper) in the vacuum electro-osmotic treatment process through a self-designed test system. Multiple aspects, including drainage volume, settlement, current, effective potential, pollutant removal efficiency, and energy consumption, were analyzed. The results indicate that using copper as an electrode material has the best dewatering effect but poorer copper pollutant removal efficiency. On the other hand, using electrokinetic geo-synthetics as an electrode material demonstrates the best copper pollutant removal efficiency, with dewatering effect second only to copper, highlighting the superiority of electrokinetic geo-synthetics material in integrated dewatering and remediation treatment. When using metal as an electrode material, the anode electrode corrosion is more severe, which significantly affects various parameters of the vacuum electro-osmotic process and the treatment outcomes. The introduction of vacuum pressure alters the conventional trend of continuous decay in effective potential during the traditional electro-osmotic process. It causes a rebound in effective potential during the later stages of treatment, and the magnitude of this rebound is influenced by the electrode material's ability to accommodate deformation.