Removal of copper(II) ions from aqueous solutions by complexation–ultrafiltration using rotating disk membrane and the shear stability of PAA–Cu complex

• Published in: Chemical engineering research & design 2018-08, Vol.136, p.712-720
• Main Authors: Tang, Shu-Yun, Qiu, Yun-Ren
• Format: Article
• Language: English
• Subjects: Aqueous solutions; Complexation; Complexation–ultrafiltration; Coordination compounds; Copper; Copper compounds; Distribution; Industrial applications; Ions; Polyacrylic acid; Radial distribution; Rejection; Rotating disk membrane; Rotating disks; Rotation; Shear induced dissociation; Shear rate; Shear stability; Sodium; Studies; Ultrafiltration
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2018.06.030

[Display omitted] •Distribution of shear rate on the membrane surface was calculated.•Shear stability of PAA–Cu complex was studied for the first time.•Shear stability of PAA–Cu complex is affected by pH.•Citical shear rate and citical shear radii of PAA–Cu complex were obtained.•Shear induced dissociation was successfully used for regeneration of PAAS. The stability of polymer–metal complex in the shear field is of great significance for the industrial applicaion of complex-ultrafiltration. The shear stability of PAA–Cu complex was investigated for the first time. Polyacrylic acid sodium (PAAS) was applied to remove Cu(II) from aqueous solutions by complexation–ultrafiltration using a rotating disk membrane. As important factors, solution pH and P/M (the mass ratio of polymer to metal ions) on the rejection of Cu(II) were investigated, and the rejection of Cu(II) could reach 99.6% at pH=6.0, P/M=25. The rotating disk was applied to generate shear rate on the membrane surface, and the radial distribution of shear rate on the membrane surface was calculated. The critical rotating speeds at which the rejection of Cu(II) begins to decrease were 1000, 900, 700rpm at pH values 6.0, 5.0, 4.0, respectively, and the corresponding critical shear rates (γc) at which the PAA–Cu complex begins to dissociate were 8.0×104, 6.6×104 and 4.2×104s−1, respectively. Furthermore, the critical shear radius and the radial distribution of substances on the membrane surface were obtained using a segmentation model. The shear stability, especially the critical shear rate of the polymer–metal complex, can give guidance to the selection of the delivery pumps so that high removal efficiency can be obtained in the industrial application of complexation–ultrafiltration. In addition, shear induced dissociation and ultrafiltration was first applied to regenerate PAAS.