| Inorganic porous materials based wide distribution range of pore size and rich topology structure, are widely used in catalysis, adsorption, separation, and especially behaving broad application in encapsulation of functional materials and medicine embedding. In the investigate history of inorganic porous materials, traditional aluminosilicate zeolites are the earliest materials with the highest industrialization degree. At the same time with regular channel structure, excellent properties of heat-resistance and acid-alkali-resistance, aluminosilicates have been played as outstanding host materials, applying in many fields, such as catalysis, adsorption and ion-exchange, etc. Through the host-guest chemistry method, functional moleculars or clusters were loaded on the structure of aluminosilicate zeolites. The novel host-guest materials obtained would have special properties which are different from single molecular, cluster and host materials, and could be investigated in the fields on optics, electronics and magnetic. In this doctoral dissertation, Sodalite based oil shale ash was used as host materials to synthesis metal (guest)-Sodalite (host) composite by ion-exchange-deoxidize method. The structure, morphology, component and channel structure were analysised. The properties of hydrogen adsorption were studied. Furthermore the hydrogen adsorption mechanism was discussed. The main conclusions are as follows:1. Microporous sodalite called SOD-1was synthesized by direct hydrothermal method and pre-process method respectively with raw material-oil shale ash. The process route and syhthesis conditions were optimized, and binary crystallization phase diagram of sodalite was drawn. In this process, we found that high basicity, relatively large mix amount of oil shale ash and high synthesis temperature are all beneficial to the formation of sodalite. Through the characterization of the products, we also found that direct hydrothermal method is the best technology route to synthesis sodalite. These conclusions provide another selection for the synthestic raw materials of oil shale ash. Furthermore it is a prerequisite work for the synthesis and utilization of host-guest composite materials. At the same time microporous zeolite SOD-2was hydrothermally synthesized from sodium silicate and sodium aluminate successfully. Binary crystallization phase diagram of SOD-2was rendered through the investigation of crystallized temperature, time and ratio of synthesis system.2. M/SOD composite materials were synthesized by ion-exchange-deoxidize method, when SOD-1was used as host and metal was used as guest. During the investigation of synthesis, it could be concluded that:(i) Ion-exchange temperature has some effects both on the structure of host materials and on the properties of composite. When the ion-exchange temperature is quiet high, the composites represent better adsorption properties.(ii)The stability of SOD-1, which was synthesized from oil shale ash, is better than SOD-2in ion-exchange process. By analysising the morphology, structure, components, channels and cages’properties of the synthesized M/SOD composite materials. The results showed that:(a) SOD type structure was kept in Fe/SOD-1composite materials with irregular polygonal morphology. In this structure, element Fe, Si and Al keep distributing consistently, which means that the guest moleculars do not agglomerate in the host materials synthesized by ion-exchange method. And host materials act as "molecular fixed framework". Meanwhile the BET surface area increased from7.6239m2·g-1to56.4825m2·g-1, the M/SOD composites possessed the ability of absorbing small molecular,(b) Ni/SOD-1and Ni/SOD-2host-guest composite materials were successfully synthesized by ion-exchange-deoxidize method from SOD-1and SOD-2. SOD type framework was kept in Ni/SOD-1composite materials with regular hexagon sheet morphology, and element Ni, Si and Al keep distributing consistently. BET surface area increased gradually belong with the enhancement of ion-exchange times, while BET surface area decreased slightly in the hydrogen deoxidized products. At the same time water absorption capacities arrived at11.36%in the products of two ion-exchange times. The adsorption/desorption isotherms of Ni/SOD-1were II type, further more, H3type hysteretic loop, which means monolayer adsorption occurred in the anterior segment and multilayer adsorption or capillary condensation occurred in the posterior segment.3. The hydrogen adsorption analysises of M/SOD (M=Fe、Ni) composite materials indicated that:(i) The hydrogen storage properties of M/SOD was better than host material SOD-1, Ni/SOD-1was better than Fe/SOD-1at normal temperature and pressure. Meanwhile this properties of M/SOD-1composite materials were superior than M/SOD-2at77K. As a result, the hydrogen adsorption capaticies of composite materials increase when the temperature decreased at normal pressure and low temperature, which could be assigned as physical adsorption of porous materials,(ii) Hydrogen adsorption rate and capacities were greatly enfluenced by the adsorption temperature at high pressure condition. At the pressure of8.00MPa, the hydrogen adsorption capaticies of M/SOD increased gradually with the the temperature was raised up. On one hand, the hydrogen adsorption capaticies of Fe/SOD-1increased from0.163wt%in298K to0.576wt%in353K. On the other hand, the maximum value for hydrogen adsorption capaticy of Ni/SOD is about0.3wt%at298k, while when the temperature is up to393k, the value reaches to0.766wt%. At the same time, when the temperature increased, the equilibrium time for the hydrogen adsorption became shorter. At normal temperature, it is difficult to reach equilibrium for M/SOD-1, But It is only24s at 373k for adsorption, and the adsorption capaticy is up to0.6wt%, and the adsorption reached to the maximum value so much as at1800s. Furthermore, there are spherical particles at the surface of M/SOD composite materials after absorbing hydrogen, which means that some paticles conglomerate at the surface. At the same time the magnetic susceptibility of M/SOD composite materials decreased after hydrogen adsorption, which shew that the antiferromagnetic coupling reducing. It could be concluded that there are interactions between hydrogen molecule and metal clusters. As a result, the mechanism of M/SOD composite materials absorbing hydrogen is not only physical adsorption and encapsulation mechanism, but also related on electron spin between metal molecule and hydrogen molecule. |
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