Preparation Of Nano-zeolite Pillared Montmorillonite Hierarchical Porous Material And Its Performance

Zeolites, as one kind of the functional materials and a hot research fields, always have been used as catalyst, adsorbents or something else, for their larger surface area, uniform pore size, better hydrothermal stability and the higher surface energy.However, the molecular diffusion limitation of the zeolite’s micropore affects the reaction in the micropore for causing the side effects and the coke blocking the pores, which leads the catalysts to lose activity. And they are no use as macromolecule catalyst for their too small pores. One of the direct solution is to decrease the size of zeolites particles. Some nano-zeolites have been synthesized in the past several years. But those nano-zeolites have a quite tendance to aggregate with each other, just like the other nano-particles. This is the main reason for blocking to apply in the large-scale.The MCMs derives, as a kind of mesopores materials, have been synthesized by the Mobil company at1992. This is a milestone for the porous material. In the mesopore, the molecular diffusion is no limitation any more. At the same time, they have the tunable pore size, the order pore structure and the thick cell wall. However, those materials are obtained as a metastable phase, which is leading to low thermal stabilities. Therefore, those materials is still no large scale use in our life.Montmorillonite, as a cheap and widespread abundance layer aluminosilicate minerals, has a long history applied in our life. For its some excellent performance such as ion-exchange performance and slack montmorillonite layer, in the past several years, the montmorillonite modification has been attracted more and more attention. With the deepening research, some advantages of those modified montmorillonite have been found, such as the larger surface, good thermal stability, strong acid. So, there is a potential application in the selective catalyst, catalytic cracking, environment protection.There are many reports focus on preparation the nano-zeolites and montmorillonite modified. However, there is rare report about nano-zeolite pillared montmorillonite or the confinement-synthesis of nano-zeolite in the montmorillonite interlamination.Nano-zeolite pillared montmorillonite has the advantages of both nano-zeolite and montmorillonite. And the nano-zeolite is no longer to aggregate with each other and the better stability, for the montmorillonite layers’confinement. Therefore, this research has important scientific and applied significance.In this paper, the route of nano-zeolite pillared montmorillonite synthesis and the performance have been discussed. Some technologis have been employed to monitored the synthesis process as well as the characterization of the material, Such as XRD pattern, SEM, TEM, N2adsorption-desorption and so on. The main research work and results are listed, as follows. 1. The nano-montmorillonite-interlamination-microreactor has been constructure, during the montmorillonite ion exchange process. Using liquid-crystal-self-assembly technology, the silicon source compound has been introduced into the nano-montmorillonite-interlamination-microreactor. Then, the linear nano-zeolite has been synthesized in the nano-montmorillonite-interlamination-microreactor under the hydrothermal conditions. This material possesses both uniform micropores (0.511nm) within the nano-zeolite pillars and mesopores (3.72nm) between the nano-zeolite pillars in the interlamellar galleries and it also has the larger surface area (541m2/g), as well.2. In this research, the routes and the conditions of constructing nano-montrnorillonite-interlamination-microreactor have been discussed. The law of montmorillonite-modification and the formation of the nano-zeolite synthesis, in the montmorillonite interlamellars, have been discussed for impeding the zeolite or SiO2to be formed out of the montmorillonite and making sure the nano-zeolite pillar formed in the interlamellar of montmorillonite.3. The copper doped mesoporous silica pillared montmorillonite has been synthesized successfully. The structure of the layer materials is reservation. And the mesoporous structure is formed in the interlamellar of montmorillonite. There is uniform slit mesopore and the pore size is becoming bigger with the increasing copper of the material. The copper is catched by Si-O-Cu bond at the silicon pillar in the interlamellar of montmorillonite, compared with the impregnated sample formed copper oxide. When the copper content is4%, the material still has the surface area of495m2/g, the mesopore size of2.75nm and the pore volume of0.68cc/g.4. A series of magnetic hybrid silica-pillared clay composites, with ordered mesopores and layered structure, have been successfully synthesized by using mixed cationic-polymeric surfactants through molecular self-assembly route. PVA-1488plays a key role in the interlayered molecular self-assembly process, not only tuning the viscosity of the gallery regions but also forming the magnetic hybrid silica-pillared clay the material has been attainable the surface area of621m/g, the mesopore size of4.17nm and the pore volume of0.75cc/g.5. The catalytic performance of nano-zeolite pillared montmorillonite was studied using the isomerization of m-xylene to p-xylene in a fixed reactor as a probe reaction. The results show that nano-zeolite pillared montmorillonite has the better catalytic activity, the conversion of15%and the selectivity of80%. The catalytic performance of copper doped mesoporous pillared montmorillonite was studied using the hydroxylation of benzene to phenol as a probe reaction. The results show that the more copper content of copper doped mesoporous pillared montmorillonite has the better catalytic activity, the most conversion of31%and the selectivity of96%. Additionally, The performance of magnetic hybrid silica-pillared clay was studied using the adsorption capacity and release of lysozyme. The results show that the lysozyme is adsorbed into the interlayered pore system and the to.5of lysozyme release time is more7hours than comparable sample when the mesopore size bigger than3nm.