Enhanced As(III) sequestration using nanoscale zero-valent iron modified by combination of loading and sulfidation: characterizations, performance, kinetics and mechanism

Abstract Nanoscale zero-valent iron (nZVI) and sulfides have been confirmed to be effective in arsenic sequestration from aqueous solution. In this study, attapulgite supported sulfide-modified nanoscale (S-nZVI@ATP) are synthesized realize the superposition effect of enhanced sequestration. The results indicated that nZVI clusters were well disaggregated BET specific surface area increased 19.61 m2·g−1 46.04 S-nZVI@ATP, resulting an removal efficiency 51.4% 65.1% at 20 min. S-nZVI@ATP mainly exist as mackinawite (FeS) causes spherical nanoparticles exhibit a larger average particle size (94.6 nm) compared bare (66.0 nm). addition, exhibited prominent ability for over wide pH range 3.0–6.0. presence anions SO42− Cl− can enhance whereas HCO3− inhibited it. adsorption by could explained pseudo-second-order kinetic model Langmuir model, with maximum capacity 193.8 mg·g−1. mechanism As(III) involved multiple processes, including precipitation conversion FeS As2S3, surface-complexation co-precipitation.