Porous NiFe-oxide nanocubes derived from prussian blue analogue as efficient adsorbents for the removal of toxic metal ions and organic dyes

A novel porous NiFe-oxide nanocubes (NiFe NCs) binary material was successfully fabricated via a facile and scalable tactic, which involved a morphology-inherited heat treating of Ni₃[Fe(CN)₆]₂·xH₂O prussian blue analogue nanocubes as self-sacrificial templates. Consequently, it was demonstrated that the NiFe NCs consisted of primary nanostructure units and interconnected pores, with an average size of ˜80 nm. When employed as adsorbents, the as-prepared NiFe NCs displayed remarkable adsorption capacities for heavy metal ions (232.3 mg g⁻¹ for As(V) and 350.71 mg g⁻¹ for Cr(VI)) and organic dyes (284.99 mg g⁻¹ for XO and 31.97 mg g⁻¹ for CR at 298 K). The resulting NiFe NCs further revealed efficient regeneration and reusability even after five consecutive adsorption/desorption cycles. The microscopic spectrum analysis demonstrated that the interaction between As(V) and NiFe NCs was mainly ascribed to the metal-oxide bonds (M–O) and hydroxyl groups (–OH), while Cr(VI) adsorption was in conjunction with the reduction reaction of Cr(VI) to Cr(III). Furthermore, the adsorption of organic dyes on NiFe NCs depended on the pore structure and molecule sizes of the organic dye molecules. These findings make cost-efficient NiFe NCs materials a powerful candidate for remediating water contaminated with inorganic and organic contaminants.