Lanthanum adsorption using iron oxide loaded calcium alginate beads

The adsorption behaviors of lanthanum (III) from an aqueous chloride medium, using iron oxide loaded calcium alginate beads were studied using equilibrium batch and column flow techniques. The effect of pH, contents of loaded iron oxide, ionic strength, adsorbent dose, contact time, and temperature on adsorption capacity of the magnetic beads was investigated. The optimum pH value was defined to be 5.0 at temperature 298 K. Kinetic and isotherm experiments were carried out at the optimum pH. It was enough to reach the adsorption equilibrium at 28 h and the maximum uptake capacity was 123.5 mg/g. Complexation, ion exchange and electrostatic interaction were all believed to play a role in lanthanum adsorption on magnetic beads. The equilibrium adsorption data were fitted to second-order kinetic equation. The Langmuir adsorption isotherm models were used for the description of the adsorption process. Furthermore, column breakthrough curves were obtained and the La (III) loaded magnetic beads were regenerated using 0.05 mol/L CaCl(2) solution. (C) 2009 Elsevier B.V. All rights reserved.