The effect of operational parameters on biosorption of Cd2+, Ni2+ and Cr6+ using Glycine max pod (Soya Bean).

Abstract

The potential of glycine max pod (GMP) in removal of Cd2+, Ni2+ and Cr6+ ions from aqueous solutions was examined in a batch adsorption process with respect to several experimental conditions including pH of solution, contact time, GMP dosage, initial metal ions concentration, and temperature, etc. The characterization of GMP was performed by using FTIR and SEM techniques. The maximum uptake of Cd2+ (1.445 mg/g), Ni2+ (1.585 mg/g) and Cr6+ (1.594 mg/g) was observed when used 2.0g of GMP biomass, 25 mgL-1 of initial Cd2+, 50 mg/l of initial Ni2+ and 50 mg/l of initial Cr+6 concentration at pH 5, 6 and 3 and contact time of 90, 60 and 90 min at room temperature for Cd2+, Ni2+ and Cr6+ respectively. The experimental data were analyzed by the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) isotherm models. The monolayer adsorption capacity Of GMP was found to be 21.56 mg/g, 53.76 mg/g and 18.87 mg/g for Cd2+, Ni2+ and Cr6+ ions, respectively. The kinetics of the adsorption was tested using pseudo-?rst-order, pseudo-second-order, Elovich and intra-particle diffusion models. The results showed that the adsorption of Cd2+, Ni2+ and Cr6+ ions onto GMP proceeds according to the pseudo-second-order model.