Taille et agglomération des cristaux d'une zéolithe au cours de la synthèse : effets des paramètres expérimentaux et modélisation

Abstract : Zeolites are an important class of natural and synthetic solids. They are used for ion exchange and adsorption, but are also widely used as catalysts and catalyst supports for the petroleum industry. ln some cases, obtaining the desired catalytic performance totally rely on the synthesis of zeolite crystals having an optimal size. ln the actual state of art, nucleation and growth of zeolite crystals are relatively well known. The initial gel, obtained by mixing of a sodium aluminate solution, an organic compound and a silicium source, is made of an amorphous solid phase and a liquid phase. However, there are in the literature few mentions about the two levels agglomeration process taking place in sorne zeolites crystallizations. The aim of this thesis is to study the hydrothermal synthesis of a specifie zeolite in order to control the sizes of crystals and their agglomeration degrees during synthesis. A methodology using XRD, SEM, AAS and PSA has then been elaborated to follow the synthesis and the evolution of those characteristics during synthesis. Once the physico-chemical and hydrodynarnic parameters (alkalinity, dilution, synthesis temperature, gel ageing, stirring speed and suspension volume) able to influence those features deterrnined, the method described above allowed the study of the influence of those parameters on the synthesis and on the various entities forrning zeolite crystals. A predictive model of sizes and agglomeration degrees, based on operating conditions, with respect to thermodynamics, kinetics and hydrodynarnics, has been elaborated. An investigative study of the influence of ultrasounds on zeolite synthesis has also been performed.
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Theses
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http://docnum.univ-lorraine.fr/prive/INPL_T_2002_PAULAIME_A_M.pdf
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https://hal.univ-lorraine.fr/tel-01750277
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Submitted on : Thursday, March 29, 2018 - 12:42:09 PM
Last modification on : Monday, April 16, 2018 - 10:41:32 AM

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Anne-Margot Paulaime. Taille et agglomération des cristaux d'une zéolithe au cours de la synthèse : effets des paramètres expérimentaux et modélisation. Alimentation et Nutrition. Institut National Polytechnique de Lorraine, 2002. Français. ⟨NNT : 2002INPL090N⟩. ⟨tel-01750277⟩

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