Sequestration of cadmium onto mango (Mangifera indica) seed biomass: Kinetics and equilibrium studies

Abstract

This study presents the removal of Cd2+ by Mangifera indica seed biomass. The adsorption process was studied as a function of pH, adsorbent dosage and contact time. Sorption kinetic models such as the pseudo-first order, pseudo-second order and the intraparticle diffusion were used to test for the adsorption process. Results showed that the adsorption kinetics followed the pseudo-second order rate equation. The adsorption process also showed an intra-particle diffusion mechanism. Langmuir and Freundlich models were used to describe the adsorption of Cd2+ on Mangifera indica seed. Biosorption equilibrium was better described by the Freundlich than Langmuir model for Cd2+. The monolayer biosorption capacities of Mangifera indica for Cd2+was 833.3 mg/g. The present investigation showed that Mangifera indica seed may be utilized as a novel low cost and easily sourced biosorbent for Cd2+ removal.