Mesoporous Molecular Sieves Synthesized And Applied Research

Much attention has been paid on the mesoporous molecular sieves, because of their large and uniform pores and their potential applications as catalyst supports, adsorbents, and hosts for various kinds of molecules and nanosize clusters. In order to improve the properties of mesoporous molecular sieves, the effects of addictives such as organic and inorganic salts, and the optimization of the synthesis technology were investigated, based on the summarizing the recent literatures of mesoporous molecular sieves. And the application of the mesoporous molecular sieves is also studied by using them as catalyst support in photocatalytic system to improve the catalytic activity.It was showed that the mesoporous molecular sieves with good crystallization degree and ordered pore structure can be obtained when the as-synthesized products were calcined at 550 C for 5 hours and the heating rate is 2 C/min. With cetyltrimethylammonium bromide as the main template, the effects of accessory templates and the effects of inorganic salts on the structure of products have been studied. It can be seen that the pore size could be extended from 3.5nm to above 4.5nm by the addition of C4H9OH or C12H25NH2, and the pore size is almost unchanged with C2H5OH for its small size. It was showed that the inorganic salts play an important role in the condensation and the structural order of the products, depending on the strength in counter-ion binding of X~ to micelles, and also relating to the amount of inorganic salts and the addition time during the crystallization process.The synthesis technologies were investigated from the following two aspects, the adjustment of pH value and heating temperature during the crystallization process. The condensation and the ordered pore structure become better when the pH adjustment was repeated twice or more during the crystallization process. It is effective to improve the condensation and the structural order by heated the initial mixture underdifferent temperature.The results obtained in application of mesoporous molecular sieves as photocatalyst support showed that, in the process of photocatalyzing the solution of Na2S, the photocatalytic activity was above five times higher than that with the usual photocatalyst.