Biosorption potential of the waste biomaterial obtained from Cucumis melo for the removal of Pb2+ ions from aqueous media: Equilibrium, kinetic, thermodynamic and mechanism analysis

The potential use of a waste biosorbent material obtained from Cucumis melo (C. melo) for the removal of Pb2+ ions from aqueous solutions was investigated by considering equilibrium and kinetic aspects. The biosorption showed a pH dependent profile. An increase in biosorbent dosage up to 1.8 g L−1 caused an increase in the biosorption yield of the biosorbent. The relatively fast biosorption at all studied temperatures follows the pseudo-second-order kinetic model. Biosorption isotherm modeling shows the equilibrium data fitted to the Langmuir model with a maximum monolayer biosorption capacity of 3.64 × 10−4 mol g−1. The thermodynamic parameters indicated the biosorption of Pb2+ on the biomass was a spontaneous and endothermic process. Experiments conducted with multi-metal system demonstrated that the presence of co-ions slightly reduced the Pb2+ biosorption capacity of the biomass. The possible Pb2+ ion-biomaterial interactions were evaluated by the zeta potential, FTIR, SEM and EDX analysis. Results of this work showed the suggested biosorbent could be an effective and eco-friendly alternative for the removal of Pb2+ ions from contaminated solutions.

► Waste biomass obtained from C. melo effectively removed Pb2+ ions.
► Pb2+ biosorption showed pH-, time- and temperature-dependent profile.
► Pseudo-second-order and Langmuir models best described the Pb2+ biosorption.
► Pb2+ biosorption takes place via ion-exchange and electrostatic interaction.