Removal of Cadmium from aqueous solution by polysaccharide produced from Paenibacillus polymyxa

This paper deals with the removal of Cadmium from aqueous solutions by polysaccharide produced from Paenibacillus polymyxa. The effects of contact time, initial metal ions concentration, mass of the polysaccharide and pH were studied. The Freundlich and Dubinin-Radushkevich (D-R) models have been applied and the equilibrium adsorption was found to best fit the Dubinin-Radushkevich adsorption isotherm based on the coefficient of correlation, R2. The maximum Cd2+ uptake was 520.09 mg g−1. An empirical modeling was performed by using a 23 full factorial design and a regression equation for adsorption of Cd2+ was determined from the data. The pH and the initial concentration of Cadmium are the most significant parameters affecting Cd2+ adsorption followed by the mass of the polysaccharide.