Organophosphonate-functionalized nanosized magnetic iron oxides as sorbents for heavy metal cations

The surface of synthetic magnetite (Fe₃O₄) and maghemite (γ-Fe₂O₃) nanoparticles was modified with phosphonic chelating compounds, 1-hydroxyethane-1,1-di(phosphonic acid) and nitrilotris(methylenephosphonic acid). The sorption affinity of functionalized magnetic iron oxides towards Niii under acidic conditions was increased by one order of magnitude.