Carbothermal-driven lattice iron engineering for synergistic photothermal oxidation of heterogeneous nanoplastics

A carbothermal-driven interfacial decoupling strategy was developed. • Robust degradation of heterogeneous NPS was achieved across a wide pH range. • Carbon-mineral domains decoupled interaction sites and pathway for disparate NPS. • A “dual-site adsorption-single-engine catalysis” mechanism was established. • Negligible metal leaching and toxicity ensure long-term environmental safety. Environmental aging induces the co-existence of heterogeneous nanoplastics with disparate surface functionalization in aquatic environments, which hamper their efficient oxidative catalytic conversion due to interfacial competition for active sites and reaction pathways. Herein, a carbothermal-driven interfacial decoupling (CDID) strategy was developed by engineering a graphene-coupled reduced vermiculite (C@rVt) photothermal catalyst. The graphene framework served as an electron donor to in-situ reduce lattice Fe 3+ in vermiculite into active Fe 2+ species, while simultaneously establishing carbon-mineral partitioned architecture. The carbon domain promoted the enrichment of hydrophobic nano-polystyrene (NPS) and facilitated molecular chain activation via localized photothermal effects. The lattice-bound Fe 2+ sites functioned as Lewis acid coordination sites to anchor amino-functionalized NPS and as redox centers that initiated peroxymonosulfate (PMS) decomposition. Benefited by the fast interface electron transfer, a robust Fe 3+ /Fe 2+ cycle was maintained across a wide pH range, leading to over 95% mixed nanoplastics catalytic oxidation and conversion at alkaline environment. This study provides a versatile paradigm for designing photothermal catalysts to treat complex multi-component plastic pollution. Download: Download high-res image (240KB) Download: Download full-size image