Polysulfone/SAPO-34 zeolite membrane impregnated with 1-ethyl-3-methyl imidazolium bis(tri-fluoromethylsulfonyl)imide ionic liquid for CO2 removal

Abstract

For improving gas separation, mixed matrix membranes (MMMs) composed of polymeric thin films and inorganic particles have been extensively developed. Although gas separation of polymeric membrane can be enhanced using inorganic particles with gas sieving properties, surface defects such as interfacial void affect their performance regularly. The voids formation is undesirable since it results in the non-selective gas permeation through MMMs. In this work, MMM was further modified with a gas selective sealing agent, ionic liquid (IL) with high CO2 solubility. Polysulfone membrane incorporated with SAPO-34 zeolite was post-impregnated with 1-ethyl-3-methyl imidazolium bis(tri-fluoromethylsulfonyl)imide. The effects of IL concentration on the membrane morphology, CO2/N2 and CO2/CH4 separation were studied. After IL modification as proven by Fourier transform infrared spectra, the interfacial defects of PSf/SAPO-34 membrane disappeared after IL modification as shown in scanning electron microscopic images. PSf/SAPO-34 membrane modified with 0.2M of IL exhibited the highest CO2/N2 and CO2/CH4 selectivity (40.15 and 35.06. respectively) among all fabricated membranes. Such enhancement in membrane performance could be attributed to the synergetic effect of IL and zeolite-based MMM.For improving gas separation, mixed matrix membranes (MMMs) composed of polymeric thin films and inorganic particles have been extensively developed. Although gas separation of polymeric membrane can be enhanced using inorganic particles with gas sieving properties, surface defects such as interfacial void affect their performance regularly. The voids formation is undesirable since it results in the non-selective gas permeation through MMMs. In this work, MMM was further modified with a gas selective sealing agent, ionic liquid (IL) with high CO2 solubility. Polysulfone membrane incorporated with SAPO-34 zeolite was post-impregnated with 1-ethyl-3-methyl imidazolium bis(tri-fluoromethylsulfonyl)imide. The effects of IL concentration on the membrane morphology, CO2/N2 and CO2/CH4 separation were studied. After IL modification as proven by Fourier transform infrared spectra, the interfacial defects of PSf/SAPO-34 membrane disappeared after IL modification as shown in scanning electron microscopic images. PS...