The Effect of Local Defects on Water Adsorption in Silicalite-1 Zeolite: A Joint Experimental and Molecular Simulation Study
| Autor: | Joel Patarin, Soulard M, Anne Boutin, Alain H. Fuchs, Trzpit M, Fabien Cailliez, Desbiens N, Isabelle Demachy |
|---|---|
| Přispěvatelé: | Laboratoire de Matériaux à Porosité Contrôlée (LMPC), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Ecole Nationale Supérieure de Chimie de Mulhouse-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Matériaux Minéraux (LMM), Laboratoire de Chimie Physique D'Orsay (LCPO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Peche, Josiane |
| Rok vydání: | 2007 |
| Předmět: |
Vapor pressure
Mineralogy 02 engineering and technology 010402 general chemistry Molecular sieve 01 natural sciences chemistry.chemical_compound Adsorption Electrochemistry General Materials Science Zeolite ComputingMilieux_MISCELLANEOUS Spectroscopy [CHIM.MATE] Chemical Sciences/Material chemistry Condensation Surfaces and Interfaces 021001 nanoscience & nanotechnology Condensed Matter Physics 0104 chemical sciences Silanol chemistry Chemical engineering Hydroxide [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph] 0210 nano-technology Water vapor |
| Zdroj: | Langmuir Langmuir, American Chemical Society, 2007, 23 (20), pp.10131-10139 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/la7011205 |
| Popis: | We report a joint experimental and molecular simulation study of water condensation in silicalite-1 zeolite. A sample was synthesized using the fluoride route and was found to contain essentially no defects. A second sample synthesized using the hydroxide route was found to contain a small amount of silanol groups. The thermodynamics of water condensation was studied in these two samples, as well as in a commercial sample, in order to understand the effect of local defects on water adsorption. The molecular simulation study enabled us to qualitatively reproduce the experimentally observed condensation thermodynamics features. A shift and a rounding of the condensation transition was observed with an increasing hydrophilicity of the local defect, but the condensation transition was still observed above the water saturation vapor pressure P0. Both experiments and simulations agree on the fact that a small water uptake can be observed at very low pressure, but that the bulk liquid does not form from the gas phase below P0. The picture that emerges from the observed water condensation mechanism is the existence of a heterogeneous internal surface that is overall hydrophobic, despite the existence of hydrophilic "patches". This heterogeneous surface configuration is thermodynamically stable in a wide range of reduced pressures (from P/P0 = 0.2 to a few thousands), until the condensation transition takes place. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|