Couple Effect of Sulfiation an Ferrous Dosing on Selenate Removal by Zerovalent Iron uner Aerobic Conitions

Both the reactivity an the removal capacity of zerovalent iron (ZVI) for the target contaminant are important for applying ZVI in wastewater treatment. In this stuy, the feasibility of combining sulfiation treatment an Fe²⁺ osing (S-ZVI/Fe²⁺) to enhance the performance of ZVI for Se(VI) removal was comprehensively investigate uner aerobic conitions. Se(VI) was first asorbe on the surface of ZVI particles an then reuce to Se(IV) an Se(0) with Se(0) being the final prouct in S-ZVI/Fe²⁺ system. This system bore the avantages of both sulfiation treatment (S-ZVI) an Fe²⁺ osing (ZVI/Fe²⁺) for Se(VI) removal. The amounts an rate constants of Se(VI) removal in S-ZVI/Fe²⁺ system were increase by 1.8-32.8 times an 11.7-194.0 times, respectively, compare to those in pristine ZVI system. Sulfiation significantly accelerate the corrosion of Fe⁰ thus improve the removal rate of Se(VI). The promoting effect of Fe²⁺ on Se(VI) sequestration by S-ZVI shoul be mainly associate with the following facts: Fe²⁺ coul maintain a relatively low pH level uring Se(VI) removal by S-ZVI; Compare to S-ZVI alone, the consumption of Fe⁰ in S-ZVI/Fe²⁺ by O₂/H⁺ was slower, an thus the electron efficiency of S-ZVI was elevate; Fe²⁺ osing facilitate electron transfer by forming semiconuctive Fe₃O₄.