Response surface methodology approach for optimization of Cu2+, Ni2+ and Pb2+ adsorption using KOH-activated carbon from banana peel

•Activated carbon (AC) with various surface functional groups was produced from banana peel by KOH-activation.•Optimization of adsorption of Cu2+, Ni2+ and Pb2+ onto AC via response surface methodology (RSM).•The adsorption isotherms were investigated using Langmuir and Freundlich models.

This study aims at optimizing the adsorption of heavy metal ions onto banana peel derived activated carbon (AC) using response surface methodology (RSM) involving central composite design (CCD). The cheap, non-toxic and locally available banana peel was subjected to carbonization and subsequently KOH-activation to produce the porous AC, which was then characterized by SEM and FTIR analyses. In RSM study, the individual and interactive effects of three critical variables including heavy metal ion concentration, pH of solution and AC dosage on the adsorption capacity were optimized. The maximum adsorption capacity appeared to follow the order: Cu2+ (14.3 mg/g) < Ni2+ (27.4 mg/g) < Pb2+ (34.5 mg/g) that agreed well with the verification experiments, revealing the reliability and suitability of the optimization approach. In addition, the results of isotherm study show that the Langmuir model can be used to best describe the adsorption behavior of Cu2+ and Ni2+ onto the banana peel derived activated carbon.