کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10377591 880739 2005 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Investigating entropy changes during gas adsorption in ETS-4
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
Investigating entropy changes during gas adsorption in ETS-4
چکیده انگلیسی
Energetic heterogeneity has been investigated for Engelhard titanium silicate Na-ETS-4 adsorbent and its Sr-exchanged variant, Sr-ETS-4. Na-ETS-4 was nearly homogeneous, while Sr exchange seemed to induce some degree of energetic heterogeneity in the sample, which diminished upon dehydration at higher temperature. Analysis of the entropy change during adsorption showed that the adsorbate molecules at low as well as moderate loading possess entropy greater than that predicted by the 2-D mobile film model, the excess being attributed to vibrational freedom. The wavelength of this vibration decreased with increasing coverage, as expected. For oxygen, the observed entropy drops in Na-ETS-4 and in Sr-ETS-4 are comparable, whereas, for nitrogen and methane, Sr exchange resulted in a greater entropy drop than in Na-ETS-4, suggesting greater restriction to movement in the Sr-exchanged sample. This study presents a simplistic yet effective understanding of the energetic behavior of the adsorbed molecules in ETS-4 adsorbent. This is vital to a thorough energetic characterization and study of the adsorption phenomenon in these new, promising adsorbents.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Colloid and Interface Science - Volume 290, Issue 1, 1 October 2005, Pages 69-75
نویسندگان
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