Surfactant-Enhanced Electrokinetic Mobilization Coupled with Perovskite-Activated Peroxydisulfate ISCO for Remediation of PCB-Contaminated Soils

Remediation of polychlorinated biphenyls (PCBs) in contaminated soils remains challenging due to their strong sorption to soil organic matter and limited accessibility to oxidants. Here, we report an integrated remediation strategy that couples surfactant-enhanced electrokinetic transport with perovskite-activated persulfate in situ chemical oxidation (ISCO) to overcome mass-transfer limitations during PCB degradation in soils. Tween 80 was employed to mobilize hydrophobic PCBs through micellar solubilization, while CaMnO 3 served as an efficient perovskite catalyst for the activation of peroxydisulfate (PDS). The combined system significantly enhanced PCB removal compared with individual treatment processes, with the Tween 80–PDS–CaMnO 3 configuration exhibiting the highest removal efficiencies for representative congeners (PCB-18, PCB-28, PCB-52, PCB-138, and PCB-153). Sustained electroosmotic flow during the 7 day electrokinetic treatment promoted effective migration of oxidants and reactive species, improving oxidant delivery within the soil matrix. Mechanistic investigations, supported by X-ray photoelectron spectroscopy analyses, revealed that CaMnO 3 activates persulfate through a reversible Mn 4+ /Mn 3+ redox cycle, while electron paramagnetic resonance confirmed the formation of SO 4 •– and • OH radicals as the dominant oxidizing species. These radicals drive sequential dechlorination of PCB molecules, transforming highly chlorinated congeners into lower-chlorinated intermediates and ultimately biphenyl. The findings demonstrate that electrokinetically assisted persulfate ISCO provides a promising and scalable approach for remediation of PCB-contaminated soils, particularly in heterogeneous or low-permeability environments where conventional oxidation processes are often ineffective.