Removal of Ni (II) and Cr (III) by complexation-ultrafiltration using rotating disk membrane and the selective separation by shear induced dissociation

Publication date: Available online 7 December 2018Source: Chemical Engineering and Processing - Process IntensificationAuthor(s): Qiang Zhang, Jing Gao, Yun-Ren QiuAbstractRemoval of Ni (II) and Cr (III) from aqueous solutions by complexation-ultrafiltration and the selective separation by shear induced dissociation were investigated using rotating disk membrane (RDM). Experiments were carried out as a function of pH and mass ratio of PAAS to metal (P/M) for the removal of Ni (II) and Cr (III) by polyacrylate sodium (PAAS) as complexing agent and the results revealed that the optimum conditions were pH 7.0 and P/M 25. Effect of rotating speed (n) on the rejection of complexes of PAAS with nickel (PAA-Ni) and chromium (PAA-Cr) at different pHs were studied and the results proved that both PAA-Ni and PAA-Cr complex would dissociate when n exceeded a certain value. The critical shear rates, at which PAA-Ni or PAA-Cr complex began to dissociate, were calculated at different pH values, and the critical shear rate of PAA-Cr complex was greater than that of PAA-Ni complex at the same pH, which indicated that the stability of PAA-Cr complex was stronger than that of PAA-Ni complex. Furthermore, the influences of operation parameters on selective separation coefficient (βNi/Cr) were investigated and the results showed that the rotating speed and pH significantly affected βNi/Cr. Finally, shear induced dissociation was used to effectively separate Ni(II) and Cr(III) and regenerate PA...

Source: Chemical Engineering and Processing: Process Intensification - December 8, 2018 Category: Chemistry Source Type: research