The poisoning effect of co-existing nitrogen upon hydrogen permeation through Pd composite membranes, consisting of thin Pd layers supported on α-Al2O3 hollow fibers, was studieds at 623 to 773K. The composite membranes were defect-free and had a high hydrogen permeance (31.2m3/m2h.bar) at 773K. When H2-activated composite membranes were exposed to nitrogen for a time, the subsequent hydrogen permeance decreased in comparison to the original value. The degree of decrease increased with decreasing temperature and with exposure time.
The Effect of Co-Existing Nitrogen on Hydrogen Permeation through Thin Pd Composite Membranes. W.Wang, X.Pan, X.Zhang, W.Yang, G.Xiong: Separation and Purification Technology, 2007, 54[2], 262-271
Table 133
Permeation of H through Pd and Pd-25wt%Ag
Alloy | Temperature (C) | P (cm2/s atm½) |
Pd | 400 | 6.7 x 10-4 |
Pd | 500 | 9.2 x 10-4 |
Pd | 550 | 1.04 x 10-3 |
Pd | 700 | 1.42 x 10-3 |
Pd-25wt%Ag | 400 | 7.9 x 10-4 |
Pd-25wt%Ag | 500 | 1.08 x 10-3 |
Pd-25wt%Ag | 550 | 1.23 x 10-3 |
Pd-25wt%Ag | 600 | 1.38 x 10-3 |
Pd-25wt%Ag | 650 | 1.52 x 10-3 |
Pd-25wt%Ag | 700 | 1.67 x 10-3 |