Selective separation and recovery of heavy metals from electroplating effluent using shear-induced dissociation coupling with ultrafiltration.

Shear-induced dissociation coupling with ultrafiltration (SID-UF) is an efficient and environment-friendly technology for the separation of heavy metal ions. In this paper, SID-UF was successfully employed for the selective recovery of nickel, zinc and copper from electroplating effluent using poly (acrylic acid) sodium (PAAS) and copolymer of maleic acid and acrylic acid (PMA) as complexants, respectively. The effects of the pH, mass ratio of polymer to metal ions (P/M) and the rotating speed on the metals removal efficiency are discussed in detail. The shear stabilities of the polymer-metal complexes were explored and the complexes critical shear rates (γc) were calculated. The results show that the order of the shear stabilities of PAA-metal complex is PAA-Zn > PAA-Cu > PAA-Ni, and that of PMA-metal complex is PMA-Cu > PMA-Ni > PMA-Zn. In addition, the construction of the stable structures of complexes and the calculation of the energies of the frontier molecular orbital by density functional theory method further predict and confirm the shear stabilities of the polymer-metal complexes.