SYNTHESIS AND CHARACTERIZATION OF WASTE EGGSHELL-BASED COBALT OXIDE AND ZINC OXIDE NANO COMPOSITE FOR ADSORPTIVE REMOVAL OF CHROMIUM(VI) FROM AQUEOUS SOLUTION

Chromium is one of the most hazardous pollutants in industrial effluents, the leather industry takes larger share. The goal of this study was, thus, to investigate the adsorptive capacity of eggshell-based cobalt oxide and zinc oxide nano composite for the removal of Cr (VI) ions from its aqueous solutions. The eggshell was cleared and pre-treated with hydrochloric acid. Then, the eggshell-based cobalt oxide and zinc oxide nano composite was synthesised by crafting cobalt and zinc oxides on treated eggshell and then calcinated at 600 °C for 3 hrs. The synthesized composite was characterized using scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, particle size analyser, BET, differential scanning calorimeter, thermal gravimetric analyses. The results reveal that the composite fulfils nano composite materials and adsorbents requirements. As was seen from the SEM image and evidenced from particle size analyser, the composite particles size was found in the range of 1.5–5 nm, the average being 2.4 nm. Besides, BET results showed that the nano composite had considerable surface (142 m2 /g) for adsorption. The nano composite as was studied using TGA showed that it can sustain up to 600 °C temperature. Moreover, the nano composite was 68.5% crystal as shown in the XRD analysis.