Modelling the Adsorption of Lead (II) Ion from Aqueous Phase with Carica papaya Trunk Activated Carbon

The study modelled the adsorption of lead (II) ion from aqueous phase using chemically activated carica papaya trunk activated carbon (CPTAC). Equilibrium and kinetics adsorption studies were conducted to investigate the adsorption capacity, adsorption isotherm and rate of adsorption respectively. The linear correlation of equilibrium data with Langmuir, Freundlich, Temkin and Hills isotherms using regression analysis showed that the adsorption of Pb fitted best into Freundlich model with R2 values of 0.874 and Kf values of 2.64 mg/g. The adsorption kinetics/rate of adsorption could be described by Pseudo second order equation with R2 value of 1.0 and 0.998 for the two adsorbate concentrations tested, indicating a chemisorption process onto heterogeneous surfaces forming multilayer on the surface of CPTAC. Modelling the equilibrium concentration adsorption of Pb onto CPTAC using XLSTAT 2014 gave a model equation as = 0.35230 + 0.13394 * Co – 0.05206 * CT – 0.32744 * pH + 0.01794 * Co2 + 0.05794 * CT2 + 0.20878 * pH2 – 0.10567 * CT – 0.13442 * Co * pH + 0.15392 * CT * pH, with R2 value of 0.75. Modelling the amount of Pb adsorbed gave a model equation as = 27.14770 + 22.36606 * Co + 0.05206 * CT + 0.32744 * pH – 0.01794 * Co2 – 0.05794 * CT2 – 0.20878 * pH2 + 0.10567 * Co * CT + 0.13442 * Co * pH – 0.15392 * CT * pH, with R2 value of 1.00.