H2 Purification Durability of Dimethoxydiphenylsilane-Derived Silica Membranes with H2–Toluene Mixtures
2013
Long-term durability tests of dimethoxydiphenylsilane-derived silica membranes for purifying H₂ from H₂–toluene mixtures were carried out. The silica membrane maintained excellent H₂-selective performance under H₂–toluene mixture condition, despite H₂ permeance was decreased from its initial value. Membrane performance changed in two steps. Performance initially decreased rapidly, and then decreased very slowly. We also examined membrane performance using H₂–dehydrated toluene and H₂–water mixtures, and it was indicated that adsorption of toluene molecules and water molecules dissolved in toluene on membrane surfaces was the predominant factor for the rapid initial decrease. Water molecules present within toluene also affected the subsequent slower decrease. These decrements were partially recovered by placing the membranes in an H₂ stream. Incomplete recovery during regeneration was due to the strong effect of water molecules dissolved in toluene, even though the amount of water was quite small.
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