Preparation Of High Hydrothermal Stability Mesoporous/Microporous-Composite Molecular Sieves

Because of its structural particularity and its unique properties, porous materials are used in many fields, such as separation, adsorption, catalysis and so on. Especially the molecular sieve materials with regular pore structure which can be directly used as catalyst or used as catalyst carrier in petroleum Refining, chemical synthesis, environmental protection and other catalytic areas have a pivotal position. The development of mesoporous molecular sieves expands the application of molecular sieve material. But its poor hydrothermal stability, largely limited its industrialization. How to improve the hydrothermal stability of mesoporous molecular sieves has always been a hot topic. It's a novel idea that the stability of pore structure and the good diffusion of mesoporous molecular sieve combined with each other to achieve the mutual complementation and the synergetic interaction between the two can solve the poor hydrothermal stability. In this paper, we mainly focused on the preparation of a micro/mesoporous molecular sieve with high hydrothermal stability.In the present paper, the precursors of Y zeolites are prepared. The recommended conditions are (15-30) Na2O:Al2O3:(20-35)SiO2:(200-400)H2O for 6 h at 85?.A polymer surfactant denoted as P123 was used as the template and Y precursors was used as the construction unit. After Y precursors were introduced into the walls of mesoporous zeolites, mesoporous zeolites showed high hydrothermal stability. The recommended conditions are pH=2, nSi/nP123/nH2O=1/0.0018/180 for 24h at 110?, condition of precursors synthesis is 20 h at 45?. Systemic characterization results revealed that the mesopore diameter and the wall thickness were about 6.50 nm and 4.50 nm, respectively. The surface area and pore volume were 759 m2/g and 0.79 cm3/g by using BET method, respectively. In addition, there remain fractions of BET surface and pore volume were about 29.0% and 57.0% after treatment at 800? for 12 h with aqueous vapor,This new Micro/mesoporous molecular sieves has high hydrothermal stability. This is a challenging work because the synthesis system is much complexity, and the results have potential benefit of development of oil domain.