Abstract:
Biosorption of lead (II) and cadmium (II) from aqueous solutions in batch system by protonated brown algae Sargassum sp. biomass was studied. The data obtained from experiments of single-component biosorption isotherms were analyzed using the Freundlich, Langmuir, Freundlich-Langmuir and Redlich-Peterson isotherm models. The Redlich- Peterson equation was found in the best fitness with the experimental data. The other models too described the isotherms of Pb2+ and Cd2+ biosorption with relatively high correlation coefficient (R2>0.93). According to the Langmuir model, the maximum uptake capacities (qm) of Sargassum sp. for Pb2+ and Cd2+ were obtained 1.70 and 1.02 mmol g-1, respectively. The optimum initial pH values for biosorption of Pb2+ and Cd2+ were determined as 4.5 and 5.0, respectively. The effect of Na+, K+, Mg2+ and Ca2+ (light metal ions) on equilibrium capacities of Pb2+ and Cd2+ biosorption was studied in the binary system at initial heavy metal ion concentration of 1 mmol L-1 and various initial concentrations of light metal ion. The effect of Na+ and K+ on the biosorption of Pb2+ was not significant, but Mg2+ and Ca2+ decreased the equilibrium capacity of Pb2+ biosorption. The presence of Na+, K+, Mg2+ and Ca2+ in solution affected the biosorption of Cd2+ considerably, so that equilibrium uptake of Cd2+ was reduced at initial concentration 6 mmol L-1 of Na+, K+, Mg2+ and Ca2+ by 10, 17, 5 and 56%, respectively.
Ramin Nabizadeh, Kazem Naddafi and Reza Saeedi , 2006. Biosorption of Lead (II) and Cadmium (II) from Aqueous Solutions by Protonated Sargassum Sp. Biomass. Biotechnology, 5: 21-26.
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