Chemical Engineering Science, Vol.107, 66-75, 2014
Mixed matrix membranes comprising MOFs and porous silicate fillers prepared via spin coating for gas separation
Different types of fillers of inorganic (titanosilicate ETS-10 and mesoporous silica type MCM-41) and organic-inorganic nature (ZIF-8 and NH2-MIL-53), with different pore size (micro- and mesoporosity) and structure, diverse particle shape, and particle sizes in the 85-400 nm range were embedded in a polysullone matrix via spin coating. Spin coating technology, widely used in the production of thin and uniform layers on porous substrates was used here to fabricate in one coating step symmetric mixed matrix membranes (MMMs) by adjusting the spinning disk velocity, rotational time, and solid concentration and volume of solution. By selecting the optimal parameters, homogeneous MMMs containing 8 wt% of the various fillers were obtained and tested for H-2/CH4 and O-2/N-2 mixed-gas separations, achieving significant improvements over the neat polymer. While NH2-MIL-53 MMMs revealed the highest separation performance (a rise in selectivity higher than 60% compared to the pure polymer for H-2/CH4 and O-2/N-2 separations), ZIF-8 MMMs showed a substantial increase in permeability (from 12.7 to 514 Barrer for H-2, and from 2.0 to 6.1 Barrer for O-2). Besides, the spin coating process enhanced solvent evaporation and reduced coat production time compared to the traditional by hand casting. (C) 2013 Elsevier Ltd. All rights reserved
Keywords:Mixed-matrix membrane;Spin coating;Mixed-gas separation;Metal-organic framework;Porous silicates;Polysulfone