zirconia

gas permeation

synthesis conditions

esterification

calcination

nano-structure

Atmospherical pollution control

Pollution prevention

Climate changes

Environmental management

Bioenergy from biomass

Climatology

A defect free nano-porous zirconia membrane was fabricated using sol-gel method for the separation of H₂ gas from a mixture of H₂ 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 α-Al₂O₃ support. The membrane had pore size of 6 nm. Membrane was fired at 400, 450, and 500ºC 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 500ºC. Scherrer’s equation was used to estimate crystallite size. TGA showed that there was no significant loss of mass above 600ºC. Gas permeance of the supported ZrO₂ layers was studied by the development of laboratory scale gas permeation setup. The permeance for H₂ and CO₂ as single component at 300ºC, respectively, was 15.21 × 10⁻⁶ and 2.0 × 10⁻⁶ mol/(m²sPa). Permeance of membrane in 75:25 H₂:CO₂ binary feed mixture was 9.96×10⁻⁶ and 1.21×10⁻⁶ mol/(m²sPa), respectively, at 300 °C. The selectivity of hydrogen over CO₂ in ZrO₂ membrane for 75:25 H₂/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.