Metal-Organic Framework Nanocomposite Thin Films with Interfacial Bindings and Self-Standing Robustness for High Water Flux and Enhanced Ion Selectivity

Tian-Yin Liu; Hao-Ge Yuan; Yuan-Yuan Liu; Dan Ren; Yi-Cheng Su; Xiaolin Wang

doi:10.1021/acsnano.8b03994

Metal-Organic Framework Nanocomposite Thin Films with Interfacial Bindings and Self-Standing Robustness for High Water Flux and Enhanced Ion Selectivity

ACS Nano. 2018 Sep 25;12(9):9253-9265. doi: 10.1021/acsnano.8b03994. Epub 2018 Aug 30.

Authors

Tian-Yin Liu^{1

2}, Hao-Ge Yuan¹, Yuan-Yuan Liu^{1

3}, Dan Ren¹, Yi-Cheng Su¹, Xiaolin Wang¹

Affiliations

¹ Beijing Key Laboratory of Membrane Materials and Engineering, Department of Chemical Engineering , Tsinghua University , Beijing 100084 , P. R. China.
² Department of Chemical Engineering , Imperial College London , South Kensington Campus , London SW7 2AZ , U.K.
³ Aerospace Research Institute of Special Material and Processing Technology , Aerospace Science and Industry Corp , Beijing 100074 , P. R. China.

PMID: 30153418
DOI: 10.1021/acsnano.8b03994

Abstract

Metal-organic framework (MOF)-based materials are promising candidates for a range of separation applications. However, the fabrication of self-standing MOF-based thin films remains challenging. Herein, a facile solution casting strategy is developed for fabricating UiO-66 nanocomposite thin films (UiO66TFs) with thicknesses down to ∼400 nm. Nanosizing UiO-66 and incorporating sulfonated polysulfone additives render high dispersity and interfacial bindings between MOFs and polymer matrices, so UiO66TFs are more mechanically robust and thermally stable than their pure-polymer counterparts. Enhanced microporosity with sub-nanometer pore sizes of the self-standing membranes enables the direct translation of UiO-66-based sorption and ion-sieving properties, thus increasing water flux and separation performance (Na₂SO₄ rejection of 94-96%) under hydraulic pressure-driven processes and eliminating internal concentration polarization in osmotic pressure-driven processes. Enhanced separation performances are achieved with water/Na₂SO₄ permselectivity of 13.5 L g^-1 and high osmotic water permeability up to 1.41 L m^-2 h^-1 bar^-1, providing 3-fold higher water/Na₂SO₄ permselectivity and 56-fold-higher water flux than polymer membranes for forward osmosis.

Keywords: forward osmosis; ion selective membrane; nanocomposite membranes; osmotic pressure driven process; self-standing nanofilm; zirconium(IV)-based metal−organic framework.