Effect of O2, Ni0 coatings, and iron oxide phases on pentachlorophenol dechlorination by zero-valent iron

Gunawardana, Buddhika; Swedlund, Peter J.; Singhal, Naresh

doi:10.1007/s11356-019-06009-w

Cited by 6 publications

(2 citation statements)

References 45 publications

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“…These XRD and Raman results were supported by SEM analyses (Supporting Information), which also revealed that iron oxides and hydroxides, including magnetite, lepidocrocite, wüstite, and goethite, for during aging of ZVI. The presence of these secondary minerals is consistent with the literature. ,,, Although magnetite and lepidocrocite are reported as stable end products of ZVI aging, additional and minor constituents, such as hematite, ferrihydrite, schwertmannite, milkasaite, and vivianite, have also been reported from ZVI aging experiments. These minerals were, however, not observed in the spectral data of the current study.…”

Section: Resultssupporting

confidence: 90%

“…The presence of these secondary minerals is consistent with the literature. 34,35,46,56 Although magnetite and lepidocrocite are reported as stable end products of ZVI aging, additional and minor constituents, such as hematite, 57 ferrihydrite, 56 schwertmannite, milkasaite, and vivianite, 48 have also been reported from ZVI aging experiments. These minerals were, however, not observed in the spectral data of the current study.…”

Section: Resultsmentioning

confidence: 99%

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Dissolved Selenium(VI) Removal by Zero-Valent Iron under Oxic Conditions: Influence of Sulfate and Nitrate

et al. 2017

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Dissolved Se(VI) removal by three commercially available zero-valent irons (ZVIs) was examined in oxic batch experiments under circumneutral pH conditions in the presence and absence of NO 3 – and SO 4 2– . Environmentally relevant Se(VI) (1 mg L –1 ), NO 3 – ([NO 3 —N] = 15 mg L –1 ), and SO 4 2– (1800 mg L –1 ) were employed to simulate mining-impacted waters. Ninety percent of Se(VI) removal was achieved within 4–8 h in the absence of SO 4 2– and NO 3 – . A similar Se(VI) removal rate was observed after 10–32 h in the presence of NO 3 – . Dissolved Se(VI) removal rates exhibited the highest decrease in the presence of SO 4 2– ; 90% of Se(VI) removal was measured after 50–191 h for SO 4 2– and after 150–194 h for SO 4 2– plus NO 3 – depending on the ZVI tested. Despite differences in removal rates among batches and ZVI materials, Se(VI) removal consistently followed first-order reaction kinetics. Scanning electron microscopy, Raman spectroscopy, and X-ray diffraction analyses of reacted solids showed that Fe(0) present in ZVI undergoes oxidation to magnetite [Fe 3 O 4 ], wüstite [FeO], lepidocrocite [γ-FeOOH], and goethite [α-FeOOH] over time. X-ray absorption near-edge structure spectroscopy indicated that Se(VI) was reduced to Se(IV) and Se(0) during removal. These results demonstrate that ZVI can be effectively used to control Se(VI) concentrations in mining-impacted waters.

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