Kinetic and equilibrium studies of lead and cadmium biosorption from aqueous solutions by Sargassum SPP. Biomass

ABSTRACT

Contamination of the aqueous environment by heavy metals is a worldwide environmental problem. Biosorption of lead [11] and cadmium [II] from aqueous solutions by brown algae Sargassum spp. biomass was studied in a batch system. The heavy metals uptake was found to be rapid and reached to 88-96% of equilibrium capacity of biosorption in 15min. The pseudo second-order and saturation rate equations were found in the best fitness with the kinetic data [R2 > 0.99]. The data obtained from experiments of single-component biosorption isotherm were analyzed using the Freundlich, Langmuir, Freundlich-Langmuir and Redlich-Peterson isotherm models. The Redlich-Peterson equation described the biosorption isotherm of Pb2+ and Cd2+ with high correlation coefficient [R2 > 0.99] and better than the other equations. The effect of Na+, K+, Mg2+ and Ca2+ on the biosorption of Pb2+ was not significant, but the metal ions affected the biosorption of Cd2+ considerably. According to the Langmuir model, the maximum uptake capacities [q m] of Sargassum spp. for Pb2+ and Cd2+ were obtained as 1.70 and 1.02mmol/g, respectively. Although the Sargassum spp. used in this study can be classified as an efficient biosorbent