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

The potential of glycine max pod (GMP) in removal of Cd 2+ , Ni 2+ and Cr 6+ 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 Cd 2+ (1.445 mg/g), Ni 2+ (1.585 mg/g) and Cr 6+ (1.594 mg/g) was observed when used 2.0g of GMP biomass, 25 mgL -1 of initial Cd 2+ , 50 mg/l of initial Ni 2+ 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 Cd 2+ , Ni 2+ and Cr 6+ 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 Cd 2+ , Ni 2+ and Cr 6+ ions, respectively.The kinetics of the adsorption was tested using pseudofirst-order, pseudo-second-order, Elovich and intra-particle diffusion models.The results showed that the adsorption of Cd 2+ , Ni 2+ and Cr 6+ ions onto GMP proceeds according to the pseudo-second-order model.