SCI和EI收录∣中国化工学会会刊

Chin.J.Chem.Eng. ›› 2019, Vol. 27 ›› Issue (3): 519-527.DOI: 10.1016/j.cjche.2018.06.026

• Separation Science and Engineering • Previous Articles     Next Articles

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

Liang Chen, Yunren Qiu   

  1. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
  • Received:2018-03-09 Revised:2018-06-18 Online:2019-04-25 Published:2019-03-28
  • Contact: Yunren Qiu,E-mail address:csu_tian@csu.edu.cn
  • Supported by:

    Supported by the National Natural Science Foundation of China (21476265).

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

Liang Chen, Yunren Qiu   

  1. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
  • 通讯作者: Yunren Qiu,E-mail address:csu_tian@csu.edu.cn
  • 基金资助:

    Supported by the National Natural Science Foundation of China (21476265).

Abstract: Removal of cadmium (Ⅱ) ions from dilute aqueous solutions by complexation-ultrafiltration using rotating disk membrane was investigated. Polyacrylic acid sodium (PAAS) was used as complexation agent, as key factors of complexation, pH and the mass ratio of PAAS to Cd2+ (P/M) were studied, and the optimum complexation-ultrafiltration conditions were obtained. The effects of rotating speed (n) on the stability of PAA-Cd complex was studied with two kinds of rotating disk, disk I (without vane) and disk Ⅱ (with six rectangular vanes) at a certain range of rotating speed. Both of the rejection could reach 99.7% when n was lower than 2370 r·min-1 and 1320 r·min-1, for disk I and disk Ⅱ, respectively. However, when rotating speed exceeds a certain value, the critical rotating speed (nc), the rejection of Cd (Ⅱ) decreases greatly. The distribution of form of cadmium on the membrane was established by the membrane partition model, and the critical shear rate (γc), the smallest shear rate at which the PAA-Cd complex begins to dissociate, was calculated based on the membrane partition model and mass balance. The critical shear rates (γc) of PAA-Cd complex were 5.9×104 s-1, 1.01×105 s-1, and 1.31×105 s-1 at pH=5.0, 5.5, and 6.0, respectively. In addition, the regeneration of PAAS was achieved by shear induced dissociation and ultrafiltration.

Key words: Complexation-ultrafiltration, Membrane, Regeneration, Shear stability, Critical shear rate, Shear induced dissociation

摘要: Removal of cadmium (Ⅱ) ions from dilute aqueous solutions by complexation-ultrafiltration using rotating disk membrane was investigated. Polyacrylic acid sodium (PAAS) was used as complexation agent, as key factors of complexation, pH and the mass ratio of PAAS to Cd2+ (P/M) were studied, and the optimum complexation-ultrafiltration conditions were obtained. The effects of rotating speed (n) on the stability of PAA-Cd complex was studied with two kinds of rotating disk, disk I (without vane) and disk Ⅱ (with six rectangular vanes) at a certain range of rotating speed. Both of the rejection could reach 99.7% when n was lower than 2370 r·min-1 and 1320 r·min-1, for disk I and disk Ⅱ, respectively. However, when rotating speed exceeds a certain value, the critical rotating speed (nc), the rejection of Cd (Ⅱ) decreases greatly. The distribution of form of cadmium on the membrane was established by the membrane partition model, and the critical shear rate (γc), the smallest shear rate at which the PAA-Cd complex begins to dissociate, was calculated based on the membrane partition model and mass balance. The critical shear rates (γc) of PAA-Cd complex were 5.9×104 s-1, 1.01×105 s-1, and 1.31×105 s-1 at pH=5.0, 5.5, and 6.0, respectively. In addition, the regeneration of PAAS was achieved by shear induced dissociation and ultrafiltration.

关键词: Complexation-ultrafiltration, Membrane, Regeneration, Shear stability, Critical shear rate, Shear induced dissociation