Efficient removal of bromate with core-shell Fe@Fe2O3 nanowires

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2017-01, Vol.308, p.880-888
• Main Authors: Shen, Wenjuan, Lin, Fangjing, Jiang, Xu, Li, Hefei, Ai, Zhihui, Zhang, Lizhi
• Format: Article
• Language: English
• Subjects: Bromate; Fe@Fe2O3 nanowires; Molecular oxygen; Removal mechanism; Surface bound Fe(II)
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2016.09.070

[Display omitted] •Bromate was efficiently removed by core-shell Fe@Fe2O3 nanowires.•Surface bound ferrous ions of core-shell Fe@Fe2O3 nanowires promoted the BrO3− removal effectively.•O2− and H2O2 favored the bromate removal with core-shell Fe@Fe2O3 nanowires, but OH inhibited. In this study, we systematically investigated the removal of bromate (BrO3−) with core-shell Fe@Fe2O3 nanowires at neutral pH, especially the effects of surface bound ferrous ions and molecular oxygen. In the presence of Fe@Fe2O3 nanowires, bromate was reduced to Br− efficiently with the generation of HOBr intermediates. Bromide species analyses and nanowires characterizations indicated that surface bound ferrous ions of core-shell Fe@Fe2O3 nanowires could effectively promote the BrO3− removal. Meanwhile, molecular oxygen competed electrons from both Fe2+ and Fe0 to generate reactive oxygen species of O2−, H2O2, and OH during the bromate removal process. Among the generated reactive oxygen species, O2− and H2O2 favored of bromate removal, but OH inhibited. We proposed a bromate removal mechanism with core-shell Fe@Fe2O3 nanowires, which suggested that the effect of surface bound Fe(II) and molecular oxygen was taken into consideration when using nZVI for bromate remediation in waters. This study can not only deepen our understanding on the bromate removal with zero valent iron, and also shed light on the design of high performance bromate removal materials.