کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
637869 1456154 2008 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Hydrothermal stability of microporous silica and niobia–silica membranes
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی تصفیه و جداسازی
پیش نمایش صفحه اول مقاله
Hydrothermal stability of microporous silica and niobia–silica membranes
چکیده انگلیسی

The hydrothermal stability of microporous niobia–silica membranes was investigated and compared with silica membranes. The membranes were exposed to hydrothermal conditions at 150 and 200 °C for 70 h. The change of pore structure before and after exposure to steam was probed by single-gas permeation measurements and nanopermporometry. The hydrothermal stability of the niobia–silica membrane was found to be higher than that of silica. After hydrothermal treatment at 200 °C, the hydrogen permeance of the niobia–silica top layer had declined by 32%, while the H2 permeance of the silica top layer was reduced by 73%. The apparent activation energies of the H2 permeance were 12.2 ± 0.2 and 15.3 ± 0.7 kJ mol−1 for silica and niobia–silica, respectively. Nanopermporometry experiments on the silica membrane were in semi-quantitative agreement with the gas permeation data. The data suggest that densification of the top layer occurred predominantly in those areas with the highest convex curvatures, thereby increasing the effective transport path of helium and hydrogen across the membrane.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Membrane Science - Volume 319, Issues 1–2, 1 July 2008, Pages 256–263
نویسندگان
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