The adsorption capacity of lead (II) on allspice is evident and its value increases when the temperature is raised. According to the kinetic model, the maximum adsorption capacity was 22.37 mg g−1 of Pb(II). Thermodynamic parameters showed that the adsorption of lead (II) onto RA was feasible, spontaneous, and endothermic under the studied conditions.
Diffusion results, the free energy value E (kJ mol−1) and XPS analysis, confirm that the lead (II) adsorption process is controlled by chemisorption. The elemental analysis and FTIR results indicate that lead is adsorbed and likely interacting with some functional groups of the cellulosic component.