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

In this study, we systematically investigated the removal of bromate (BrO 3 − ) with core-shell Fe@Fe 2 O 3 nanowires at neutral pH, especially the effects of surface bound ferrous ions and molecular oxygen. In the presence of Fe@Fe 2 O 3 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@Fe 2 O 3 nanowires could effectively promote the BrO 3 − removal. Meanwhile, molecular oxygen competed electrons from both Fe 2+ and Fe 0 to generate reactive oxygen species of O 2 − , H 2 O 2 , and OH during the bromate removal process. Among the generated reactive oxygen species, O 2 − and H 2 O 2 favored of bromate removal, but OH inhibited. We proposed a bromate removal mechanism with core-shell Fe@Fe 2 O 3 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.