Preparation of Pd-based membranes on Pd/TiO2 modified NaX/PSS substrate for hydrogen separation: Design and optimization

摘要

Porous stainless steel/NaX nanozeolites/Palladium (Pd)/TiO2 (PSS/NaX/Pd/TiO2) membrane was prepared by sol gel method and its application was investigated for hydrogen separation. NaX nanozeolites were synthesized using microwave heating method and coated by vacuum-assisted method on the PSS surface. The prepared membranes were characterized using SEM, and XRD analysis. The Box-Behnken design was used to determine the relation between synthetic and process variables including NaX content (0.5-1.5 g), Pd/TiO2 percentage (2-10%), pressure difference (2-4 bar) and temperature (350 -450 degrees C) on the hydrogen permeation flux and H-2/N-2 ideal selectivity. By optimization of parameters, the experimental maximum hydrogen permeation flux and ideal selectivity were found to be 0.245 mol/m(2) s and 1025, respectively. Moreover, the performance of fabricated PSS/NaX/Pd/TiO2 membrane was investigated for different mixtures of H-2/N-2 in optimum conditions. The results indicated that hydrogen fluxes and H-2/N-2 separation factor were remarkably decreased by increasing N-2 content. The obtained results suggests that the incorporation of Pd/TiO2 composite into the Pd-based membranes and optimization of parameters can be effective method for increasing the performance of Pd-based membranes in hydrogen separation. (C) 2016 Elsevier Inc. All rights reserved.