摘要：Ability of isolated cyanobacterium for removal of cadmium and lead from aqueous solutions was evaluated. Influence of procedural parameters including initial metal concentration, pH, temperature and algal biomass quantity on removal efficiency was assayed. Analysis of intracellular-removed heavy metal by graphite furnace atomic absorption spectrometry using optimized conditions was studied. Developed modification of graphite furnace operational conditions for introduction of a larger volume of sample through five separate injections was used to measure concentrations undetectable by routine graphite furnace program. Maximum removal efficiency of Pb2+ and Cd2+ were obtained in 60 mg/L (95.8 percent) and 50 mg/L (77.5 percent) concentrations respectively. Optimum conditions for removal of Pb2+ were observed in pH 5.5, temperature 35° C and biomass dosage 2g/L. Removal efficiency of Cd2+ peaked under conditions of pH 6.5, temperature 30° C and culture density 2g/L. Surface adsorption was main mechanism of heavy metal removal, showing inconsiderable role of intracellular removal. EC50 value for Pb2+ and Cd2+ was found to be 67 mg/L and 43 mg/L respectively. Devised method of graphite furnace operation led to an interference- free analysis as well as reaching lower detection limit. This study established possibility for employment of as biosorbent for cadmium and lead removal from contaminated solutions.
