Gas separation performance of C/CMS membranes derived from poly(furfuryl alcohol) (PFA) with different chemical structure

Carbon molecular sieve (CMS) membranes derived from two kinds of PFAs synthesized by oxalic acid and iodine catalyst were prepared respectively. In order to investigate the effect of chemical structure of the PFAs on properties of their CMS membranes, TG, FTIR, XRD and HRTEM were employed to characterize the microstructural change of CMS membranes during pyrolysis. Gas separation performance of CMS membranes was also investigated by molecular probe study with pure gases (H2, CO2, O2, N2 and CH4). The results show two kinds of PFAs are composed of a large amount of same function groups by different cross-linking style, which was confirmed by their similar FTIR spectra and slightly different TG curves. After pyrolysis, there are significant differences in microstructure and gas permeation for resultant CMS membranes. The PFA-OA carbon membrane exhibits high carbon yield, smaller d0 0 2 value (interlayer spacing) and short, slightly irregular but roughly parallel fringes in HRTEM. In contrast, the PFA-I carbon membrane shows a higher gas permeability and lower gas permselectivity in gas permeation experiments.