The removal of Cu2+, Ni2+ and Methylene Blue (MB) from aqueous solution using Luffa Actangula Carbon: Kinetics, thermodynamic and isotherm and response methodology

The removal of Cu2+, Ni2+ and Methylene blue onto agricultural waste Luffa Actangula Carbon (LAC) was carried out. The surface morphology and functional group study for LAC was done by FTIR, SEM and EDAX technique. The data was best fitted by Pseudo 2nd order kinetic model. The equilibrium was attained in 120 min at pH 6 for Cu2+ with maximum adsorption capacity of 12.47 mg g−1 and pH 6 for Ni2+ with maximum adsorption capacity of 6.2 mg g−1 at 30 °C. The equilibrium for MB was attained in 120 min at 30 °C at pH 7 with maximum adsorption capacity of 10.32 mg g−1. The methodology of Response Surface was used to study the process variables like contact time and pH and their interaction with removal efficiency as response. The data was nonlinearly fitted by Freundlich isotherm model for Cu2+ and Ni2+ ion with Regression coefficient of Cu2+ (0.965) and Ni2+ (0.950) whereas in case of MB it was best fitted nonlinearily by Langmuir Isotherm with higher regression coefficient(0.954) and smaller ᵡ2 value. The LAC shows higher adsorption capacity in the order of Cu2+ (12.47 mg g−1)> MB (10.32 mg g−1)> Ni2+ (6.2 mg g−1). The Langmuir monolayer adsorption capacity is in the order of Cu2+ (33.16 mg g−1)>MB (24.84 mg g−1)> Ni2+ (23.84 mg g−1). The data was also predicted by statistical error analysis tool like HYBRID, ARE. The Thermodynamic parameters ∆G° ∆H° ∆S° have been decided and it was found that the process was feasible, spontaneous and exothermic in nature. © 2017