Dynamic magnetic capture-catalytic pyrolysis for aquatic micro- and nanoplastic management

Micro- and nanoplastics (MNPs) in aquatic systems pose global ecotoxicological threats, yet their effective removal and end-treatment remain challenging. Here, we develop a dynamic magnetic capture (DynMagCap) system that enables efficient and universal removal of MNPs via in situ chemical magnetization. Unlike conventional magnetic seeding methods, DynMagCap generates Fe-based dynamic magnetic chains that self-assemble, migrate, and interlink with MNPs under bubble assistance. This system achieves over 99% removal efficiency across various MNP types, sizes, and water conditions, demonstrating high robustness. The captured Fe-MNP composites are further valorized via catalytic pyrolysis (CatPyr), during which where Fe species catalyze chlorine fixation from polyvinyl chloride (PVC)-bearing MNPs into FeCl₂ while producing Fe/C nanocomposites active for water electrolysis. Techno-economic and life-cycle analyses confirm the environmental and economic viability of the integrated DynMagCap-CatPyr route. This work establishes a magnetic separation-coupled catalytic conversion platform that bridges pollution remediation with circular resource utilization.