Unveiling the Role of Mackinawite and Fe Components in Arsenic(III) Removal by Sulfidated Zero-Valent Iron under Aerobic Conditions.

In this study, we synthesized microscale sulfidated zerovalent iron (S-mZVI) with controllable mackinawite (FeS) content up to nearly 100 wt % and investigated the roles of FeS and Fe for arsenite (As(III)) sequestration under aerobic conditions. Batch experiments show that FeS and Fe contents determine the kinetics and longevity of As removal by S-mZVI, respectively. The Fe/FeS galvanic cell accelerates the consumption of Fe by dissolved oxygen (DO) while preserving FeS to preferentially remove As as sulfide, which is protected from oxidation by Fe.