MOF-containing mixed-matrix membranes for CO₂/CH₄ and CO₂/N₂ binary gas mixture separations

• Published in: Separation and purification technology 2011-09, Vol.81 (1), p.31-40
• Main Authors: Basu, Subhankar, Cano-Odena, Angels, Vankelecom, Ivo F.J
• Format: Article
• Language: English
• Subjects: aluminum; Applied sciences; Asymmetry; Carbon dioxide; Chemical engineering; coatings; evaporation; Exact sciences and technology; Fillers; Membranes; Phase shift; Reluctance; scanning electron microscopy; Separation; silicone; solvents; Voids
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2011.06.037

Both dense and asymmetric metal organic frameworks (MOFs) containing membranes were respectively prepared by solvent evaporation and phase inversion with Matrimid® as base polymer and three different MOFs: [Cu₃(BTC)₂], ZIF-8 and MIL-53(Al) as filler. Incorporation of the fillers in the membranes resulted in an increase in thermal and mechanical stability of the membranes. However, the highest filler loadings (typically 40wt%) deteriorated the properties of the membrane. An optimized priming protocol of the fillers before membrane preparation resulted in a homogeneous distribution of the MOFs, as confirmed with SEM. The possible presence of non-selective voids in the asymmetric membranes was overcome by coating a highly permeable silicone polymer layer on top of the MMMs. Dense membranes and asymmetric membranes for all the three studied MOFs showed improvement in CO₂/CH₄ and CO₂/N₂ selectivity and permeance as compared to the unfilled reference membrane.