▎ 摘　　要

Coating Ni and Co nanoparticles (NPs) with graphene oxide (GO) make them comparable to FeNPs in removing nitrate from water. Specifically, NaBH4 reduction of Fe3+, Ni2+ and Co2+, in the presence of GO affords quantitative yields of their corresponding magnetically functionalized nanocomposites: Ni@r-GO, Co@r-GO as well as Fe@r-GO. Efficiencies of Ni@r-GO and Co@r-GO prove comparable to that of Fe@r-GO in the removal of nitrate from water. The latter demonstrates a superior efficiency over the previously reported unanchored FeNPs. Characterizations are carried out by SEM, AFM, FT-IR, UV vis, XRD, RAMAN and VSM. Considering the advantages of Ni and Co over Fe, this approach opens up the availability of a new class of graphene-based composites, with unique properties and outstanding performance, for nitrate removal from water. (C) 2014 Elsevier Ltd. All rights reserved.