Enthralling Adsorption of Different Dye and Metal Contaminants from Aqueous Systems by Cobalt/Cobalt Oxide Nanocomposites Derived from Single-Source Molecular Precursors

Abstract

The cobalt/cobalt oxide nanocomposites (Co/CoO NCs), NC-1 and NC-2 were synthesized from our recently reported single-source molecular precursors (SSMPs) [Co(hep-H)(H2O)4]SO4, (1) and [Co(hep-H)2(H2O)2](NO3)2, (2), [hep-H= 2-(2-hydroxylethyl) pyridine], respectively, via wet-chemical reduction method. Our purpose was to study the effect of different counter anions (i. e. SO4 2− and NO3 −) of precursors on the surface properties of synthesized materials. Both the nanocomposites were characterized by Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and Brunauer–Emmett–Teller (BET) analysis. Two distinct morphological as well as surface features have been obtained using 1 and 2 viz. variable spheres (NC-1) with low surface area and flakes (NC-2) with high surface area. The adsorption behavior of these nanocomposites on industrial dyes and heavy metals showed excellent dye adsorption (99.6% to 97.2%) and good to moderate metal adsorption efficiency of NC-1. The NC-1 could be recycled up to five times for dyes and three times for metals, advocating its practical applications in industry. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim