es9b04956_si_001.pdf (2.06 MB)
Coupled Effect of Sulfidation and Ferrous Dosing on Selenate Removal by Zerovalent Iron Under Aerobic Conditions
journal contribution
posted on 2019-12-03, 15:33 authored by Peng Fan, Yuankui Sun, Baoxue Zhou, Xiaohong GuanBoth the reactivity and the removal capacity of zerovalent
iron
(ZVI) for the target contaminant are important for applying ZVI in
wastewater treatment. In this study, the feasibility of combining
sulfidation treatment and Fe2+ dosing (S-ZVI/Fe2+) to enhance the performance of ZVI for Se(VI) removal was comprehensively
investigated under aerobic conditions. Se(VI) was first adsorbed on
the surface of ZVI particles and then reduced to Se(IV) and Se(0)
with Se(0) being the final product in S-ZVI/Fe2+ system.
This system bore the advantages of both sulfidation treatment (S-ZVI)
and Fe2+ dosing (ZVI/Fe2+) for Se(VI) removal.
The amounts and rate constants of Se(VI) removal in S-ZVI/Fe2+ system were increased by 1.8–32.8 times and 11.7–194.0
times, respectively, compared to those in pristine ZVI system. Sulfidation
significantly accelerated the corrosion of Fe0 thus improved
the removal rate of Se(VI). The promoting effect of Fe2+ on Se(VI) sequestration by S-ZVI should be mainly associated with
the following facts: Fe2+ could maintain a relatively low
pH level during Se(VI) removal by S-ZVI; Compared to S-ZVI alone,
the consumption of Fe0 in S-ZVI/Fe2+ by O2/H+ was slower, and thus the electron efficiency
of S-ZVI was elevated; Fe2+ dosing facilitated electron
transfer by forming semiconductive Fe3O4.