Recovery of Hg(II) from aqueous solution by complexation-ultrafiltration using rotating disk membrane and shear stability of PMA-Hg complex

Abstract

Copolymer of acrylic acid and maleic acid (PMA) was used to remove Hg2+ from aqueous solution by complexation-ultrafiltration (C-UF) through rotating disk membrane (RDM). The effects of P/M (mass ratio of PMA to metal ions), pH and rotation speed (N) on the interception of Hg2+ were investigated. The interception could reach 99.7% at pH 7.0, P/M 6 and N less than 1890 r/min. The shear stability of PMA-Hg complex was studied by RDM. The critical rotation speed, at which the interception starts to decrease, was 1890 r/min, and the critical shear rate, the smallest shear rate at which PMA-Hg complex begins to dissociate, was 2.50×105 s−1 at pH 7.0. Furthermore, the critical radii were obtained at different rotation speeds and pHs. The results showed that the critical radius decreased with the rotation speed and increased with pH. Shear induced dissociation coupling with ultrafiltration (SID-UF) was efficiently used to recover Hg2+ and PMA.