Polyethersulfone based MMMs with 2D materials and ionic liquid for CO2, N2 and CH4 separation

Abstract

Increasing concerns on global warming and climate change have led to numerous attempts on developing new membrane materials to reduce excessive CO2 emission into the atmosphere. In the present work, we focused on the separation of CO2 from gas mixtures through two-dimensional (2D) materials based mixed matrix membranes (MMMs). The ionic liquid (IL) 1-Ethyl-3methylimidazolium bis (trifluoromethylsulfonyl) imide together with different weight fractions (0.5–1.5 wt %) 2D materials, such as molybdenum disulfide (MoS2) and hexagonal boron nitride (h-BN), were homogenously blended to prepare polyether sulfone (PES) MMMs. The main aim was to investigate the effect of the addition of 2D materials on the gas separation/permeation properties of the PES membranes. Pure gas permeation for N2, CO2, and CH4 and binary gas mixtures separation for CO2/N2 and CO2/CH4 were investigated through pure PES and modified PES membranes. The prepared membranes were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and water contact angle tests. The gas permeabilities were found to be improved by average 15–20 times higher compared to pure PES. The αCO2/CH4 and αCO2/N2 were improved up to 124% and 18% using PES/h-BN (1 wt %)/IL and PES/MoS2 (1.5 wt %)/IL combination, respectively. In overall, 2D materials and IL together as a filler into PES matrix revealed a significant improvement in the gas separation/permeation properties of PES and can be considered as a competent membrane for CO2/CH4 and CO2/N2 separation.