Polydimethylsiloxane/postmodified MIL-53 composite layer coated on asymmetric hollow fiber membrane for improving gas separation performance

Composite layer containing postmodified MIL-53 (P-MIL-53) was exploited to be coated on as-fabricated asymmetric hollow fiber membrane for improving gas separation performance. The morphology and pore size distribution of P-MIL-53 particles were characterized by SEM and N-2 adsorption isotherm. The EDX mapping and FTIR spectra were performed to confirm the presence of P-MIL-53 deposited on the outer surface of hollow fiber membranes. The results of pure gas permeation measurement indicated that incorporation of P-MIL-53 particles in coating layer could improve permeation properties of hollow fiber membranes. By varying coating times and P-MIL-53 content, the membrane coated with PDMS/15%P-MIL-53 composite by three times achieved best performance. Compared to pure PDMS coated membrane, CO2 permeance was enhanced from 29.96 GPU to 40.24 GPU and ideal selectivity of CO2/N-2 and CO2/CH4 also increased from 23.28 and 26.95 to 28.08 and 32.03, respectively. The gas transport through composite membrane was governed by solution-diffusion mechanism and CO2 preferential adsorption of P-MIL-53 contributed to considerable increase of CO2 solubility resulting in accelerated permeation rate. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44999