LAUSR

Abstract In this study, brown algae Sargassum sp. and its alginate extraction products were used as biosorbents for removal of nickel and copper ions from aqueous solutions in batch. The alginate extraction was performed in sodium carbonate solution at 80 °C and the calcium alginate beads were produced using the drip method. The point of zero charge of the biosorbents were determined. Biosorption kinetics were relatively fast and the equilibrium were reached between 90 and 360 min. Biosorption isotherms showed that the calcium alginate beads have higher biosorption capacity. However, the extraction residue and Sargassum sp. in nature have greater metal-biosorbent affinity. The Langmuir model was well-adjusted to the experimental results. Metal biosorption was strongly affected by solution pH. EDX spectra suggest the ion exchange mechanism from light metals with the target ions. FTIR spectra before and after metal biosorption indicated the presence of carboxylate, sulfonic, ether, alcohol and amide groups.