Fabrication of nZVI/rGO via an innovative thermal co-reduction method for enhanced PFAS removal through sequential adsorption and photocatalytic degradation.

This study investigates the synthesis, characterization, and performance of nanoscale zero-valent iron/reduced graphene oxide (nZVI/rGO) nanohybrids for the efficient removal of per- and polyfluoroalkyl substances (PFAS). The magnetic nanohybrids were fabricated using an innovative thermal co-reduction method, enabling scalable production under inert conditions. Comprehensive characterization confirmed successful integration of nZVI onto rGO sheets, and nanohybrids exhibited high surface area, strong magnetic properties, and effective adsorption and photocatalytic degradation capabilities for PFAS. PFAS removal was explored through sequential adsorption followed by photocatalytic degradation under UVC irradiation. Batch experiments demonstrated rapid adsorption equilibrium within 3 h, removing 98.2 % of perfluorooctanoic acid (PFOA) and 97.6 % of perfluorooctane sulfonate (PFOS) under dark conditions. Subsequent oxygen-free UVC treatment with nZVI/rGO significantly degraded PFOS and PFOA, reducing their concentrations from 1 mg/L to 0.78 and 1.01 μg/L, respectively, with the formation of short-chain PFAS. Defluorination reached 64.2 % for PFOA and 57.8 % for PFOS after 72 h, demonstrating effective PFAS degradation by nZVI/rGO. Desorption studies confirmed the potential for nanohybrid regeneration and reuse, while iron release analysis demonstrated minimal leaching. These results indicate that thermally reduced nZVI/rGO nanohybrids offer a scalable, efficient material for PFAS remediation, particularly through adsorption followed by degradation under oxygen-free UVC irradiation.