| 摘要： |
Nanomaterials incorporation in polymer membranes has been widely recognized as an effective strategy to improve membrane performance in filtration such as desalination. However, the poor compatibility between nanomaterials and polymer matrix restricts the enhancement of rejection because of unavoidable defects. In this work, we present a nanocomposite membrane by incorporating a kind of well-compatible polymeric nanomaterial, dopamine-melanin nanospheres with functional groups in cellulose triacetate (CTA) to improve the separation performance. The abundant amine and hydroxyl groups of dopamine-melanin nanospheres, not only contribute to the increase of membrane hydrophilicity for enhancing water flux, but also improve the interfacial compatibility between dopamine-melanin nanospheres and CTA matrix for maintaining excellent rejection. More significantly, the negative charges of dopamine-melanin nanospheres intensify the zeta potentials of membrane, which enhances the salt rejection by Donnan effect. The optimal NC-0.4 membrane yielded water flux of 22 L m(-2) h(-1) and high rejections to salts, MgSO4 (97.6%) > Na2SO4 (96.5%) > MgCl2 (91.8%) > NaCl (76.1%), owing to the synergistic effect of size exclusion and electrostatic repulsion. Moreover, the NC-0.4 membrane obtained excellent rejections to monovalent and bivalent ions. Therefore, blending well-compatible polymeric nanomaterials with polymer matrix could be an effective strategy to develop high-performance membrane for desalination. |
