Removal of mercury(II) from aqueous solutions by biosorption on the biomass of Sargassum glaucescens and Gracilaria corticata

Abstract

Previous studies have shown the batch removal of Pb2+ ions from wastewater and aqueous solution using two different algae; Gracilaria corticata (red algae) and Sargassum glaucescens (brown algae). The objective of this research is to study the batch removal of Hg2+ from aqueous solution, and wastewater using marine dried red algae G. corticata (red algae) and S. glaucescens (brown algae). Marine alga was used as a low-cost absorbent. The effects of pH, biosorption time and the concentration of the Hg2+ solution were examined in the adsorption process with S. glaucescens and G. corticata. Results showed that when we used S. glaucescens as the biosorbent, optimum conditions of pH, Hg2+ concentration and equilibrium time were at 5, 200ppb and 90min, and when G. corticata was used, these conditions were at 7, 1000ppb and 30min. The equilibrium adsorption data are fitted to the Frundlich isotherm model, by both S. glaucescens and G. corticata. The Hg2+ uptake by S. glaucescens was best described by the first-order rate model and G. corticata was best described by the second-order model.