AUTHOR=Mei Xueyi , Yang Sheng , Lu Peng , Zhang Yexin , Zhang Jian 

TITLE=Improving the Selectivity of ZIF-8/Polysulfone-Mixed Matrix Membranes by Polydopamine Modification for H2/CO2 Separation

JOURNAL=Frontiers in Chemistry

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00528

DOI=10.3389/fchem.2020.00528

ISSN=2296-2646

ABSTRACT=<p>Gas separation membranes are essential for the capture, storage, and utilization (CSU) of CO<sub>2</sub>, especially for H<sub>2</sub>/CO<sub>2</sub>separation. However, both glassy and rubbery polymer membranes lead a relatively poor selectivity for H<sub>2</sub>/CO<sub>2</sub> separation because the differences in kinetic diameters of these gases are small. The present study establishing the mixed matrix membranes (MMMs) consist of a nano-sized zeolitic imidazolate frameworks (ZIF-8) blended with the polysulfone (PSf) asymmetric membranes. The gas transport properties (H<sub>2</sub>, CO<sub>2</sub>, N<sub>2</sub>, and CH<sub>4</sub>) of MMMs with a ZIF-8 loading up to 10 wt% were tested and showing significant improvement on permeance of the light gases (e.g., H<sub>2</sub> and CO<sub>2</sub>). Moreover, the depositional polydopamine (PDA) layer further enhanced the ideal H<sub>2</sub>/CO<sub>2</sub> selectivity, and the PDA-modified MMMs approach the Robeson upper bound of H<sub>2</sub>/CO<sub>2</sub> separation membranes. Hence, the PDA post-modification strategy can effectively repair the defects of MMMs and improved the H<sub>2</sub>/CO<sub>2</sub>selectivity.</p>