Selenate removal by zero-valent iron under anoxic conditions: effects of nitrate and sulfate
| dc.contributor.author | Das, Soumya | |
| dc.contributor.author | Lindsay, Matthew | |
| dc.contributor.author | Hendry, M. Jim | |
| dc.date.accessioned | 2019-11-08T18:45:30Z | |
| dc.date.available | 2019-11-08T18:45:30Z | |
| dc.date.issued | 2019-08-16 | |
| dc.description.abstract | Batch experiments were conducted to examine aqueous Se(VI) removal by zero-valent iron (ZVI) under anoxic conditions in the presence and absence of NO3− and SO42−. Initial concentrations for Se(VI), SO4, and NO3–N of 5 mg L−1, 1800 mg L−1, and 13 mg L−1, respectively, were employed to mimic mine waters. In the control experiment, 90% Se(VI) removal occurred within 1.5 h without SO42− and NO3− (B1). This removal threshold was reached after 3 h with NO3− added (B3) and after 33 h with SO42− added (B2). Removal reached 90% after 42 h with both SO42− and NO3− added (B4). Modeled Se(VI) removal rates consistently followed first-order kinetics and revealed that the presence of SO42− and, to a lesser extent, NO3− inhibited Se(VI) removal. Increases in pH and Fe coupled with decreasing Eh are consistent with ZVI corrosion under anoxic conditions. Transmission electron microscopy, Raman spectroscopy, and X-ray diffraction revealed magnetite [Fe3O4] and lepidocrocite [γ-FeOOH] formed at ZVI surfaces during the experiments. X-ray absorption near edge structure spectroscopy indicated that Se(VI) was predominantly reduced to Se(0) (70–80%), but Se(IV) (10–13%) and Se(-II) (2–13%) were also detected at reacted ZVI surfaces. Overall, the results show that although SO42− and NO3− present in mine wastes can reduce reaction rates, Se(VI) removal by ZVI under anoxic conditions is associated with extensive reduction to insoluble Se(0). | en_US |
| dc.description.sponsorship | NSERC Discovery Grant (Grant No. RGPIN-2014-06589); NSERC Industrial Research Chair (Grant No. 184573) | en_US |
| dc.description.version | Peer Reviewed | en_US |
| dc.identifier.citation | Das, S., Lindsay, M.B.J., & Hendry, M.J. (2019). Selenate removal by zero-valent iron under anoxic conditions: Effects of nitrate and sulfate. Environmental Earth Sciences, 78, 528. https://doi.org/10.1007/s12665-019-8538-z | en_US |
| dc.identifier.doi | 10.1007/s12665-019-8538-z | |
| dc.identifier.issn | 1866-6280 | |
| dc.identifier.issn | 1866-6299 | |
| dc.identifier.uri | http://hdl.handle.net/10388/12444 | |
| dc.language.iso | en | en_US |
| dc.publisher | Springer Nature | en_US |
| dc.subject | zero-valent iron | en_US |
| dc.subject | selenium | en_US |
| dc.subject | treatment | en_US |
| dc.subject | geochemistry | en_US |
| dc.subject | mine waste | en_US |
| dc.subject | sulfate | en_US |
| dc.subject | nitrate | en_US |
| dc.title | Selenate removal by zero-valent iron under anoxic conditions: effects of nitrate and sulfate | en_US |
| dc.type | Article | en_US |
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