Enhanced gas permeability by fabricating functionalized multi-walled carbon nanotubes and polyethersulfone nanocomposite membrane

Nanocomposite membranes consisting of 1-10 wt.% multi-walled carbon nanotubes (MWCNTs) embedded in polyethersulfone (PES) have been fabricated via phase inversion method by using N-methyl-2-pyrrolidone as solvent and their transportation properties are evaluated. The functional groups on MWCNTs, crystalline structure and MWCNTs dispersion were characterized by Fourier transform infrared spectroscopy, X-ray diffraction spectra, field emission scanning electron microscopy and transmission electron microscopy. The gas permeation fluxes of the derived nanocomposite membranes are increased by similar to 67% without sacrificing selectivity at 5 wt.% MWCNTs introduced. According to diffusivity and solubility results derived from time lag method, the carboxyl groups on MWCNTs have stronger interaction with CO2, which can increase the solubility of polar gas and limit the solubility of non-polar gas, thus benefiting the CO2/N-2 gas selectivity. (c) 2011 Elsevier B.V. All rights reserved.