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

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 o C with a specific surface area of 133 m 2 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 max ) 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. Dye and metal-ion adsorption on COPYGO. • A heterogeneous porous nanocomposite COPYGO was synthesized from cobalt oxide polypyrrole on graphene oxide. • COPYGO was the optimized adsorbent among the other synthesized nanocomposite. • Adsorption evaluation confirms the Langmuir model and pseudo second order for all pollutants. • The endothermic adsorption is spontaneous in nature for all wastewater effluents. • COPYGO showed a very high removal efficiency for all MB, Pb(II) & Cd(II) pollutants.