Articles - Chemical Science & Engineering Research

Abstract

The kinetic, equilibrium and thermodynamic study of the adsorption of Pb²⁺, Ni²⁺ and Cu²⁺ ions from aqueous solution by the leaf biomass of Psidium Guajava (Guava) leaves were investigated at different experiment condition. Optimum condition of pH, Contact time, biomass dosage, initial metal ion concentration and temperature were determined, the maximum adsorption capacity was found to be 9.88, 9.5 and 4.21 mg/g, for Pb²⁺, Ni²⁺ and Cu²⁺, respectively. The kinetic studies indicated that the adsorption process of the Pb²⁺, Ni²⁺ and Cu²⁺ ions followed the pseudo-second-order model with R² value of 1.0, 1.0 and 0.674 respectively. Equilibrium studies showed that the adsorption of Pb²⁺, Ni²⁺ and Cu²⁺ are well represented by both Freundlich and Langmuir isotherms with the Langmuir model given a better fit for Pb²⁺ with R² value of 0.990 and Langmuir constant KL of 4.878, while Freundlich model was better fit for Ni²⁺ and Cu²⁺ ions with R² value of 0.892 and 0.471 respectively, Freundlich constant K_f value of 1.8923 and 0.0196 and (ΔG⁰ -1705.02, -3745.18 and 401.18 KJmol^-1) showed that the adsorption of pb²⁺ and Ni²⁺ are spontaneous, While Cu²⁺ are non-spontaneous. These finding indicate that the leaves biomass of Psidium guajava could be used for the adsorption of Pb²⁺, Ni²⁺ and Cu²⁺ ions from industrial effluents.