Polycationic Polymer-Regulated Assembling of 2D MOF Nanosheets for High-Performance Nanofiltration

• Published in: ACS applied materials & interfaces Vol. 9; no. 33; pp. 28079 - 28088
• Main Authors: Ang, Huixiang, Hong, Liang
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 23.08.2017
• Subjects: cations; cobalt; coordination polymers; copper; divalent metals; dyes; energy conservation; graphene; iron; nanofiltration; nanosheets; porphyrins; zinc; assembly; two-dimensional; polycation; nanofiltration; metal−organic framework
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/acsami.7b08383

Herein, a two-dimensional metal–organic framework (2D MOF) made of iron porphyrin complex (TCP­(Fe)) interconnected with divalent metal ion (M = Zn, Co, and Cu) is used to construct a selective layer, which is explored as an ultrafast and energy-saving nanofiltration (NF) membrane for removing organic dyes from water. Among the layered 2D M-TCP­(Fe) membranes, Zn-TCP­(Fe) membranes display the highest water permeance, which is 3 times higher than graphene-based membranes with similar rejection. To further improve the separation performances, we utilize polycations to anchor the periphery carboxylic groups of nanosheets, regulating the assembly of 2D Zn-TCP­(Fe) nanosheets to produce a new class of crack-free selective layer possessing ultrathin and highly ordered nanochannels for efficient NF. Benefiting from these structural features, our polycation-regulated 2D Zn-TCP­(Fe) membranes could offer ultrahigh permeance of 4243 L m–2 h–1 bar–1 (2-fold higher than its pristine) and excellent rejection rates (over 90%) for organic dye with size larger than 0.8 × 1.1 nm. This permeance value is about 2 orders of magnitude higher than the commercial polymeric NF membrane. Additionally, the membranes demonstrate 20–40% salt rejection.