Ionic Liquid Blend Thin Film Composite Membrane for Carbon Dioxide Separation

Abstract

To utilize the superior properties of ionic liquid (IL), this work developed thin film composite (TFC) membrane incorporated with [EMIM][Tf2N] prepared via interfacial polymerization (IP). The effect of IL on membrane properties and CO2/CH4 separation performance were studied. The IL loading was varied from 1-5wt%. The fabricated membranes were characterized and the gas separation performance of the membranes was evaluated in term of CO2 permeability and CO2/CH4 selectivity. Analysis from Fourier-transform Infrared Spectroscopy (FTIR) shows the presence of [EMIM][TF2N] functional groups proving the successful attachment of the IL in the membrane. Furthermore, it is noted that with increasing IL loading up to 3vol%, the surface morphology became rougher and the membrane became more rigid based on the Differential Scanning Calorimeter (DSC) thermogram and Atomic Force Microscopy(AFM) analysis, accordingly. Based on the gas permeation test at 1 bar feed pressure, membrane with 5wt% of IL showed CO2 permeability of 3424.44 GPU and CO2/CH4 selectivity of 32.15. Compared to pure TFC membrane, TFC/IL membranes showed as much as 103 times and 32 times improvement for CO2 permeability and CO2/CH4 selectivity, accordingly. The improved gas separation performance shows promising results of incorporating IL in TFC membrane for CO2 separation.