Abstract
A defect free nano-porous zirconia membrane was fabricated using sol-gel method for the separation of H-2 gas from a mixture of H, and CO2. Agglomeration of sol was controlled by releasing hydrolyzing water slowly by the reaction of solvent such as alcohol and acetic acid unlike conventional technique. FE-SEM image of ten times coated membrane showed a uniform zirconia layer of 885 nm thickness, coated on alpha-Al2O3 support. The membrane had pore size of 6 mn. Membrane was fired at 400, 450, and 500 degrees C to remove organic content, to estimate the final calcination temperature. XRD study confirmed that the zirconia was transformed into tetragonal phase. The crystallite size (D) was 5.0, 10.13, and 16.28 nm for dried and calcined zirconia powder respectively, at 25, 400 and 500 degrees C. Scherrer's equation was used to estimate crystallite size. TGA showed that there was no significant loss of mass above 600 degrees C. Gas permeance of the supported ZrO2 layers was studied by the development of laboratory scale gas permeation setup. The permeance for H 2 and CO2 as single component at 300 degrees C, respectively, was 15.21 x 10(-6) and 2.0 x 10(-6) mol/(m(2)sPa). Permeance of membrane in 75:25 H-2:CO2 binary feed mixture was 9.96x10(-6) and 1.21x10(-6) mol/(m(2)sPa), respectively, at 300 degrees C. The selectivity of hydrogen over CO2 in ZrO2 membrane for 75:25 H-2/CO2 binary feed mixture was 8.23. These results demonstrated that the membranes offer high potential for purification of hydrogen and carbon dioxide in a mixture at an elevated temperature.