Calotropis procera mediated one pot green synthesis of Cupric oxide nanoparticles (CuO-NPs) for adsorptive removal of Cr(VI) from aqueous solutions

The present study deals with the synthesis of CuO-NPs via green route and investigated its application for removal of Cr(VI) from aqueous solutions. The experimental parameters were optimized through Box-Behnken Design (BBD) of response surface methodology for the optimum response. The adsorption equilibrium data was well fitted to Freundlich isotherm model and the kinetics was explained through pseudo-second-order kinetic model. The overall process was feasible, spontaneous and exothermic. Linear approach for analysing the isotherm as well as kinetic parameters was found more appropriate than the non-linear approach. The adsorbent was successfully regenerated and reused up to five consecutive cycles without significant loss in removal capacity. The experimental results exhibited that CuO-NPs can be a good alternative for Cr(VI) removal from aqueous solutions.