Potential of brown algae biomass as new biosorbent of Iron: Kinetic, equilibrium and thermodynamic study

The brown alga Sargassum Vulgare was used as biosorbent for Fe^3+ ions removal in aqueous solution. The biosorption studies of the algae biomass were executed in batch system. The biosorbent was characterized using FTIR, SEM, BET and elemental analysis. Several parameters were inspected in order to find the optimum biosorption conditions of Fe^3+ removal as a function of pH, contact time, biomass dosage and initial metal concentration. Langmuir and Freundlich isotherms were found applicable in terms of relatively high regression values. The maximum adsorption capacity of the biosorbent obtained from the Langmuir adsorption isotherm was found about 19.86 mg/g, at 120 min contact time, pH=2, 5 g/L algae dosage, and 298K temperature.The thermodynamic parameters of the process (ΔG, ΔH and ΔS) were estimated from tests carried out at different temperatures (298, 308 and 318 K). The Kinetics of sorption followed the first order model. The Gibbs free energy and the enthalpy were negative (-5.69 ΔG - 3.16kJ/mol; ΔH = -23.24kJ/mol) indicate that the biosorption was a spontaneous and exothermic process. FT IR results of algal biomass indicate that biomass has different functional groups able to react with metal ion in aqueous solution. The Biosorbent could be regenerated three times using 0.001M EDTA solution, with 94% recovery.