PIM-1/PDMS hybrid pervaporation membrane for high-efficiency separation of n-butanol-water mixture under low concentration

Abstract

Mixed matrix membranes (MMMs) prepared by blending nanocomposites and organic polymers are attractive for producing new materials with improved characteristics such as good hydrophobicity, excellent permeate flux and high separation factor in pervaporation (PV). In order to overcome the aggregation of inorganic nanofillers in membrane and the leakage of inorganic nanoparticles from hybrid membrane in separation process, the polymers of intrinsic microporosity (PIMs) materials with unique properties were successfully synthesized and employed as organic microporous fillers owning good affinity with polymer matrix. The PIM-1/polydimethylsiloxane (PDMS) hybrid pervaporation membranes were then fabricated by mutual combination of the rigidity of PIM-1 and the flexibility of PDMS. The organophilic PIM materials were discovered to provide definite improvements in enhancing the interfacial compatibility and solvent resistance ability to achieve defect-free membrane. Various techniques including FTIR, SEM, EDS, NMR, GPC, contact angle goniometry, N2 absorption/desorption, pervaporation measurements and swelling tests were used to characterize and evaluate the properties of PIMs and membranes. Compared with the pristine PDMS membrane, the prepared PIM-1/PDMS pervaporation membrane exhibited superior permeate flux of 1425.3 g m−2 h−1 and competitive separation factor of 30.7 in the separation of n-butanol–water system under a very low concentration of 1.0 wt%. Moreover, the membrane displayed excellent stability and integrity even over 240 hour’s long-term continuous operation, which showed great potential for industrial application.