Kinetics, equilibrium and thermodynamic studies of the adsorption of zinc (II) ions on carica papaya root powder

Abstract

The adsorption of Zn (II) ions on Carica papaya was studied. The effect of pH, biomass dosage, temperature, adsorption equilibrium and kinetics, were investigated. The optimum pH for the removal of Zn(II) was found to be 6.0. The Freundlich, Langmuir and Dubinin–Radushkevich (D–R) models were used for the mathematical description of the adsorption equilibrium of which the Freundlich and D-R fitted very well to the experimental data. The adsorption kinetics was well described by the pseudo-second order equation. The thermodynamic studies and sorption energy calculation using D-R isotherm model indicated that the adsorption processes were exothermic and physical in nature.