Biosorption of Methyl Blue (MB), Fuchsin Acid (FA), Rhodamine B (RB), Methylene Blue (MEB), Bromocresol purple (BC) and Methyl Orange (MO) onto Sargassum ilicifolium were studied in a batch system. Effect of dye structure on biosorption by Sargasuum ilicifolium was studied to define the correlation between chemical structure and biosorption capacity. Different dye groups such as triarylmethane (MB, FA and BC), monoazo (MO), thiazine (MEB) and Xanthene (RB) were studied. At optimum experimental conditions for each dye, biosorption capacitiy was determined and compared. The results indicate that the chemical structure (triarylmethane, monoazo, thiazine, Xanthene), number of sulfonic groups, basicity (element of chromophore group: S, N, O) and molecular weight of dye molecules influence their biosorption capacity. Experimental parameters such as biosorbent dose, pH, contact time, initial dye concentration were optimized for each dye. The biosorption kinetic data was successfully described by the pseudo second-order model. The biosorption results were also analyzed by the Langmuir and Freundlich isotherms. Finally, biosorption capacities obtained using Sargassum ilicifolium was compared with the ones presented in the literature.
