Thin zeolite T/carbon composite membranes supported on the porous alumina tubes for CO2 separation

Thin zeolite T/carbon composite membranes (thickness about 3-4 mu m) with the favorable CO2 separation performances were successfully synthesized on the porous alumina tubes by dispersing zeolite T particles (particle size about 300 nm) into polymeric precursor (polyfurfuryl alcohol (PFA)). The composite membrane is carbonized under the condition of 873 K with a dwell time of 2 h and ultra-high purity N-2 flowing. The CO2 separation performance is influenced by the zeolite contents and dip-coating cycles of the composite membranes. The zeolite T/carbon composite membrane synthesized with zeolite contents of 2 wt.% and two coating cycles displayed the best CO2 separation performance. The single and mixed gases permeation properties of the composite membrane were investigated in detail. Due to the competitive permeation effect between adsorbable gas (CO2) and non-adsorbable gas (N-2 and CH4) in the membrane, the CO2/CH4 and CO2/N-2 permselectivities (143 and 67.1) in the equimolar mixed gas system were higher than the results from single gas permeation test (97.3 and 51.6) at temperature of 298 K. The effects of permeation temperature and pressure difference on CO2 separation performances of the composite membranes were also studied. The CO2/CH4 and CO2/N-2 selectivities decreased with increasing the permeation temperature or increasing the pressure difference. The zeolite T/carbon composite membrane introduced in this paper can be a novel membrane candidate for industrial CO2 separation. (c) 2013 Elsevier Ltd. All rights reserved.