Optimizing Heavy Metal Uptake in Carpobrotus aequilaterus Through Electrokinetic Treatment: A Comprehensive Study on Phytoremediation from Mine Tailings

Abstract

Copper mining drives economic growth, with the global demand expected to reach 120 million metric tons annually by 2050. However, mining produces tailings containing heavy metals (HMs), which poses environmental risks. This study investigated the efficacy of phytoremediation (Phy) combined with electrokinetic treatment (EKT) to increase metal uptake in Carpobrotus aequilaterus grown in tailings from the Metropolitan Region of Chile. The plants were exposed to varying voltages and treatment durations. In the control (no EKT), the root metal contents were Fe (1008.41 mg/kg) > Cu (176.38 mg/kg) > Mn (103.73 mg/kg) > Zn (30.26 mg/kg), whereas in the shoots, the order was Mn (48.69 mg/kg) > Cu (21.14 mg/kg) > Zn (17.67 mg/kg) > Fe (27.32 mg/kg). The optimal EKT (15 V for 8 h) significantly increased metal uptake, with roots accumulating Fe (5997.24 mg kg−1) > Mn (672 mg kg−1) > Cu (547.68 mg kg−1) > Zn (90.99 mg kg−1), whereas shoots contained Fe (1717.95 mg kg−1) > Mn (930 mg kg−1) > Cu (219.47 mg kg−1) > Zn (58.48 mg kg−1). Although EKT enhanced plant growth and biomass, higher voltages stressed the plants. Longer treatments were more effective, suggesting that EK–Phy is a promising method for remediating metal-contaminated tailings.