Overcoming configuration and fouling limitations in capacitive deionization for efficient multicomponent PFAS capture

Given the environmental persistence of per- and polyfluoroalkyl substances (PFAS) and the growing prevalence of short- and ultrashort-chain alternatives, treatment approaches that remain effective in multicomponent and matrix-challenging waters are urgently needed. In this study, we develop an integrated membrane capacitive deionization (IMCDI) system using mesoporous carbon hollow sphere (MCHS) electrodes coated with a polyvinyl alcohol/polyethyleneimine (PVA/PEI) hydrogel. The PVA/PEI layer functions as an inductive interface that promotes the enrichment and inward transport of perfluorocarboxylic acids (PFCAs) during electrosorption, followed by selective capture within the mesoporous, hydrophobic MCHS framework, which also alleviates membrane fouling limitations in conventional MCDI. The system demonstrates consistent removal trends in a mixed PFCA solution ranging from C3 to C8 (10 mg/L each), including improved uptake of weakly removed short- and ultrashort-chain species. Configuration benchmarking shows that MCHS-based ACDI is effective at environmentally relevant concentrations, whereas IMCDI is designed to target the removal of high PFAS levels and achieves higher charge utilization, with a charge efficiency (CE) of 66.1%. Notably, the integrated membrane electrode (IME) maintained excellent operational stability and anti-fouling resilience, with performance retention exceeding 80% across both 20 cycles in synthetic multicomponent solutions and 10 stress cycles in real industrial wastewater. Furthermore, the IMCDI system achieves 68.66% removal in industrial wastewater with an energy intensity of 1.07 Wh g^-1 PFOA removed. Overall, these results demonstrate that interfacial reconfiguration can improve PFAS-targeted electrosorption and reduce fouling sensitivity in complex, high-loading waters.