Towards fabrication of low-cost carbon/ceramics membranes: Substrate modification

This paper presents a novel method for fabrication of carbon membrane for gas separation by mean of surface modification with a conventional 2B pencil on the low-cost macroporous Al2O3 substrate. The resulting membrane was characterized by SEM, which shows that the modified membrane is continuous and uniform without defects. Gas permeation experiments were conducted by single gas measurements (test gas: H-2, CO2, O-2 and N-2) at 20-80 degrees C under 100-400 kPa. The results show that the pencil lead layer can effectively prevent deep infiltration of precursor solution into the pores of substrate, and that gas transport through carbon membrane follows the molecular sieving mechanism. Based on the modified substrate, the carbon membrane exhibits good permeability (up to the order magnitude of 10(-9) mol/m(2) s Pa) and separation capability such as H-2/N-2 of 37.3, CO2/N-2 of 11.2, and O-2/N-2 of 8.3.