Nanocomposite MFI-ceramic hollow fibre membranes via pore-plugging synthesis: Prospects for xylene isomer separation

Nanocomposite MFI-alumina hollow fibres and membrane tubes have been prepared by pore-plugging hydrothermal synthesis and tested in the separation of xylene vapour mixtures. Single component and ternary xylene isomer mixtures diluted in N2 gas have been fed into the membrane lumen, while N2 gas swept over the outer membrane surface. The fibres showed a maximum p-xylene flux of 4.5 μmol m2 s−1 at 573 K for p/m/o-xylene partial pressures 0.62 kPa/0.27 kPa/0.32 kPa, the pxylene to o-xylene (p/o) separation factor showing a value of 107. As expected for a nanocomposite material, xylene fluxes show no indication of flux increase beyond 573 K due to pore opening. When comparing MFI-alumina hollow fibres to membrane tubes, the surface-to-volume ratios can be increased by one order of magnitude, allowing for more compact and cost-effective units.