Recovery of cerium(III) from aqueous solutions by complexation—ultrafiltration process

Abstract

ABSTRACTComplexation–ultrafiltration process was investigated for cerium(III) recovery from aqueous solutions by using poly (acrylic acid) sodium salt (PAASS) as a complexing agent. The adsorption of cerium(III) on PAASS was preliminarily studied at different pH values. Next, effects of pH, polymer metal ratio (PMR), calcium(II) and competitive complexing agents on permeate flux (J) and cerium rejection coefficient (R) were investigated in the total recirculation mode. Finally, the integrations of four experiments including concentration, decomplexation, regeneration of PAASS and reuse of regenerated PAASS were carried out. Obtained results show that the adsorption can be described well using the Langmuir equation. If pH is reduced below 4, J decreases rapidly. PMR has negligible effect on J. R increases with increasing pH or PMR. Calcium(II) and ethylenediaminetetraacetic acid disodium salt have the effects on R, but these effects can decrease by increasing pH. Tartrate sodium does not influence R. In the process of concentration, J declines slowly, and R is about 1. It takes 40 min to reach the decomplexation equilibrium at pH 3. The decomplexation percentage of cerium(III)–PAASS complex is about 70%. In the regeneration of PAASS, cerium(III) can be removed effectively, and the purification of regenerated PAASS is acceptably satisfactory. The binding capacity of regenerated PAASS is close to that of fresh PAASS, and the recovery percentage of binding capacity is higher than 90%. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.