Nickel-Substituted Polyoxometalate Nanomaterial as a Green and Recyclable Catalyst for Dye Decolorization

摘要

The catalytic activity of a synthesized nanopolyoxometalate (alpha(2) P2W17NiO61)(8-) was investigated in the decolorization of methyl orange (MO) using KMnO4 as an oxidant in aqueous medium. This catalyst was synthesized by the incorporation of nickel into the polytungstic matrix of a lacunar compound (alpha(2) P2W17)(10-) which was prepared from a saturated parent molecule (alpha P2W18)(6-). For characterization, the applied methods, IR, UV-vis, and XRD, have been studied. The optimal experimental conditions were achieved at: pH 6, 25 degrees C, 10 mg/L of MO concentration, 0.1 mM of oxidant concentration, and 0.3 g of catalyst mass. Under these conditions, the discoloration efficiency obtained was 90.75%. The presence of chloride and sulfate ions showed the inhibitory effect on the discoloration efficiency. At the end of the discoloration reaction, the catalyst was recovered, washed, and reused in several cycles keeping its catalytic activity intact.