KINETIC STUDIES ON THE SORPTION OF LEAD AND CADMIUM IONS FROM AQUEOUS SOLUTIONS BY CALADIUM BICOLOR (WILD COCOYAM) BIOMASS

Abstract

Kinetic investigations are necessary for determining the rate of reaction and mechanism. The kinetics of the sorption of Pb²⁺ and Cd²⁺ from aqueous solution on to the biomass of C. bicolor was studied by batch equilibrium technique. The removal of the two metal ions was found to be > 60% depending on the initial metal ion concentration during the contact time. The maximum sorption was found to be 75.11 mg/g and 25.30 mg/g for Pb²⁺ and Cd²⁺ at an equilibrium contact time of 150 min. The process of uptake is governed by film-diffusion controlled pseudo-second order reversible rate kinetics. The sorption capacity at any contact time has been evaluated and a Langmuir-type model equation has been developed to predict the optimized minimum operating time to determine a specific amount of metal ion sorption.



KEY WORDS: Sorption kinetics, Contact time optimization, Water treatment, Heavy metals removal


Bull. Chem. Soc. Ethiop. 2005, 19(1), 89-102.