Polypyrrole functionalized Cobalt oxide Graphene (COPYGO) nanocomposite for the efficient removal of dyes and heavy metal pollutants from aqueous effluents

Abstract

A cobalt oxide graphene nanocomposite functionalized with polypyrrole (COPYGO) having a heterogenous porous structure was synthesized using hydrothermal method. Microscopic imaging of the COPYGO surface revealed its highly porous and ordered features. The adsorption performance of the COPYGO composite was systemically investigated for Methylene Blue (MB), Congo red (CR) dyes and toxic lead (Pb(II)) and Cadmium (Cd(II)) metals. These were selected as they are the common pollutants in industrial wastewater. The COPYGO was found to be thermally stable up to 195 oC with a specific surface area of 133 m2 g?1. Experimental data indicates that the COPYGO follows Langmuir and Temkin adsorption isotherm. The COPYGO was efficient in removing MB (92.8%), CR (92.2%), Pb(II) (93.08%) and Cd(II) (95.28%) pollutants at pH 7.2, 5.0, 5.5 and 6.1 respectively from the simulated effluents. The maximum adsorption capacity (Q<inf>max</inf>) observed for MB 663.018 mg g-1, CR 659.056 mg g-1, Pb(II) 780.363 mg g?1 and Cd(II) 794.188 mg g?1 pollutants. The thermodynamic analysis of the COPYGO indicates that the adsorption is endothermic and spontaneous in nature. COPYGO showed very high efficient removal rate for the pollutants in simulated effluents which guaranteed its benefits and efficacy in industrial wastewater treatment. © 2021 Elsevier B.V.