Das Soumya, Lindsay Matthew B J, Essilfie-Dughan Joseph, Hendry M Jim
Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Canada SK S7N 5E2.
ACS Omega. 2017 Apr 17;2(4):1513-1522. doi: 10.1021/acsomega.6b00382. eCollection 2017 Apr 30.
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 and SO . Environmentally relevant Se(VI) (1 mg L), NO ([NO-N] = 15 mg L), and SO (1800 mg L) were employed to simulate mining-impacted waters. Ninety percent of Se(VI) removal was achieved within 4-8 h in the absence of SO and NO . A similar Se(VI) removal rate was observed after 10-32 h in the presence of NO . Dissolved Se(VI) removal rates exhibited the highest decrease in the presence of SO ; 90% of Se(VI) removal was measured after 50-191 h for SO and after 150-194 h for SO plus NO 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 [FeO], 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.
在有氧批次实验中，于环境相关的中性pH条件下，在有和没有NO和SO的情况下，研究了三种市售零价铁（ZVI）对溶解态硒（VI）的去除效果。使用与环境相关的硒（VI）（1 mg/L）、NO（[NO-N]=15 mg/L）和SO（1800 mg/L）来模拟受采矿影响的水体。在没有SO和NO的情况下，4-8小时内实现了90%的硒（VI）去除。在有NO的情况下，10-32小时后观察到类似的硒（VI）去除率。在有SO的情况下，溶解态硒（VI）的去除率下降最为显著；根据所测试的ZVI不同，对于SO，50-191小时后测得90%的硒（VI）被去除，对于SO加NO，150-194小时后测得90%的硒（VI）被去除。尽管批次和ZVI材料之间的去除率存在差异，但硒（VI）的去除始终遵循一级反应动力学。对反应后固体进行的扫描电子显微镜、拉曼光谱和X射线衍射分析表明，ZVI中存在的Fe(0)会随着时间的推移氧化成磁铁矿[FeO]、方铁矿[FeO]、纤铁矿[γ-FeOOH]和针铁矿[α-FeOOH]。X射线吸收近边结构光谱表明，在去除过程中，硒（VI）被还原为硒（IV）和硒（0）。这些结果表明，ZVI可有效用于控制受采矿影响水体中的硒（VI）浓度。
