Study on the equilibrium and kinetics of nickel (II) adsorption on cellulose from peanut shell modified with chitosan

In this study, cellulose was produced by activating peanut shells with 5% NaOH as an alkaline agent and bleaching with 5 wt.% H2O2. Before being modified with chitosan, the cellulose was slightly oxidized with ammonium persulfate to introduce carboxyl groups. The equilibrium and kinetics of nickel adsorption on the as-prepared material were investigated. Langmuir, Freundlich, and Temkin isotherm models were used to describe the equilibrium isotherms. The Langmuir and Temkin adsorption isotherms were better fits to the equilibrium data than the Freundlich equation. The Langmuir monolayer adsorption capacity of nickel ions on cellulose from peanut shells modified with chitosan was found to be 25.70 mg/g. The Temkin adsorption constant was calculated as 0.45 kJ/mol. Therefore, the interaction between nickel ions and the surface of the as-prepared material are assumed to be weak. Kinetic data were evaluated by pseudo-first-order and pseudo-second-order models, and rate constants were determined. Simulations demonstrated that the pseudo-second-order equation could adequately describe the adsorption of nickel ions.