Biosorption of lanthanum from aqueous solutions using magnetic alginate beads

Magnetic alginate beads are potential biosorbent for sorption of lanthanum(III) from an aqueous medium. Batch experiments were carried out to study the equilibrium, kinetics, and thermodynamics of lanthanum sorption. The effects of initial solution pH, initial lanthanum concentration, and temperature on lanthanum sorption were investigated. The optimum pH value was defined to be 4. Kinetic and isotherm experiments were carried out at the optimum pH. It was enough to reach the adsorption equilibrium at 4 hours, and the maximum uptake capacity was (1.8 mmol g^?1) at 25°C. Uptake kinetics and sorption isotherms were obtained and modeled using conventional and simple equations: best results were respectively obtained with the pseudo-second-order rate equation and the Langmuir equation. The La(III) loaded magnetic alginate beads were regenerated using 0.1 M CaCl₂ without activity loss.