Sorption of Cadmium and Lead Ions by Cunninghamella elagans Lender ML2

CUNNINGHAMELLA elegans Lender was isolated from agricultural field treated with sewage industrial effluents. It was selected on the basis of its high frequency for the biosorption potential evaluation of cadmium and lead. Alkali pretreated dead biomass was used for biosorption experiments. The effects of biomass concentration, initial metal concentration, pH, contact time, temperature and agitation rate were studied. The maximum uptake capacities of cadmium and lead ions are 59 mg/g and 71 mg/g dry wt biomass at an initial concentration of metal ions 300 mg/L and 200 mg/L biomass dosage, respectively. The optimum pH values for cadmium and lead biosorption were 5.0 and 6.0. The best temperature was 25oC for cadmium and lead ions. Maximum uptake of cadmium was achieved after 60min, while for lead after 30 min. The best agitation rate was 120rpm for both metal ions removal. The technique of scanning electron microscope coupled with energy dispersive X-ray analysis (EDAX) shows that cadmium and lead were exchanged with elements present on the surface of native cells of C. elegans Lender ; thereby suggesting ion exchange as one of the dominant mechanisms of metal biosorption for this fungal strain. Alkali pretreated biomass was tested to remove cadmium and lead ions from three wastewater samples. Cadmium and lead ions were effectively eluted by 15 mM HNO3 and 10 mM EDTA, respectively.