SELECTIVE SEPARATION OF Mn(II) AND Cd(II) AS WELL AS REGENERATION OF POLYMER VIA SHEAR INDUCED DISSOCIATION COUPLING WITH ULTRAFILTRATION

Abstract

The selective separation of Mn(II) and Cd(II) as well as regeneration of the complexing agent were conducted by shear induced dissociation coupling with ultrafiltration (SID-UF), and the copolymer of maleic acid and acrylic acid (PMA) was used as complexing agent. At the optimal complexation conditions, pH 6 and P/M (mass ratio of polymer to metal ions) 9, both the rejections of Mn(II) and Cd(II) arrived at more than 99%. The shear stabilities of two PMA-metal complexes at different pHs were particularly investigated using rotating disk membrane and the results indicated that critical shear rates γ _c of PMA-Mn complex were lower than that of PMA-Cd at the same pH. According to the difference of the shear stabilities between PMA-Mn and PMA-Cd complexes, the selective separation of Mn(II) and Cd(II) were achieved by SID-UF at 1450 rpm and 1600 rpm, and PMA was regenerated.

Keywords:
Ultrafiltration; Shear stability; Critical shear rate; Selective separation coefficient; Regeneration