The Research On The Seed-Assisted Method Preparing ZSM-5 And Beta

Nowadays, energy and environmental issues have been enduring topics. Finding out a method which can make an efficient and convenient, green, inexpensive production of molecular sieve has a great significance and have the potential application for industrial production. In recent years, the synthesis of various types of molecular sieve system is focused on the solid phase, which has the advantages of high one-pot production and low reactor requirements. Based on previous research results, this paper uses solid phase synthesis system while the traditional process uses template agent. Molecular sieve product is added as seeds to induce the generation of specific molecular sieve, that synthesis route is named as 'the solid phase seed-assisted method'.The selection of raw materials in the research is almost consistent with the traditional hydrothermal synthesis method. In the research, molecular sieves can synthesis successfully without any template agent, and the raw materials are non-toxic harmless. Its unique ratio and reaction condition leads to a efficient, environmental protection, cheap ZSM-5 zeolite synthesis. The samples (hereinafter referred to as ZSM-5-S) using this method characterized by XRD, BET and TPD found various parameters and now compared to the industrial-grade ZSM-5 products which have some advantages. These advantages are:(?) precursors only needs traces of water, significantly reduce the use of water which exists as a solvent in traditional process; (?) greatly reduces the internal solvent pressure of the reaction vessels, reducing the risk of preparation and equipment costs; (?) increased capacity utilization of vessels; (?) don't add any template, which has high product yield and environmentally friendly at the same time.Meanwhile, many parameters of ZSM-5 and Beta molecular sieve which were prepared by the solid phase seed-assisted method were characterized by such as feeding silica alumina ratio, seed amount, water content, crystallization time and alkaline. The experimental results show that both the hydrothermal synthesis method and the solid phase seed-assisted method can synthesis of two kinds of molecular sieves successfully. The water content of precursor has a great effect on the crystallization of ZSM-5 molecular sieve. And we can control the crystallization of ZSM-5 under low alkaline. But Beta crystallization need high alkaline content.As is known to all, exploring the growth mechanism of the molecular sieve and the understanding of mechanism of the synthesis of molecular sieves has a critical significance. Practice has proved that the new molecular sieves synthesis methods of development cannot leave the study of the mechanism of crystal growth. Research on the mechanism of the solid phase seed-assisted method practice some reaction law of synthesis of molecular sieves. After all, these laws of the solid phase seed-assisted method can have a certain reference on the industrial application.