Synthesis Of MFI Zeolite Films On Different Substrates

Zeolite films, a kind of inorganic films developed in recent 10 years, which have small and uniform pores and the character of Si/Al-adjustable and can be substituted by other kinds of atom are wildly used in the fields of adsorption and separation, chemical sensors and catalytic reactions. In the process of zeolite films synthesis, the properties of the substrates can strongly influenced the growth of zeolite films, exhibit high sensitivity to the substrates. Therefore, the relationship between the substrates and the zeolite films is the hotspot of the research and also be an important precondition of application.1. Silicalite-1 zeolite films are hydrothermally synthesized on the surfaces of glass and quartz oscillators separately by using TEOS and colloidal silica (CS) as silica sources. Effects of different silica sources and different substrates have been investigated. Results indicate that, under the same condition of zeolite synthesise, when using glass as substrate b-oriented Silicalite-1 zeolite films would be more easily gained by using TEOS as silica source than CS; while using quartz oscillator as substrate it will easier to synthesized Silicalite-1 zeolite film by using CS as silica sources than TEOS but totally b oriented .2. QCM sensor has been designed and built up according to piezoelectric effect of the quartz oscillator. The relationship between the thickness of zeolite film and the starting frequency of the quartz oscillator and the influence of the calcination has been investigated. Results indicate that the best condition of starting frequency is 5.15MHz when the thickness of Silicalite-1 zeolite film is 2μm. In the process of calcination, the golden electrode has fallen off the quartz oscillator and seriously influenced the conductivity. Therefore, we have put forward a new strategy to solute the problem that synthesize the silicliate-1 zeolite film and calcinate it before sputter the golden electrode on the oscillator.3. Silicalite-1 zeolite film has been hydrothermally synthesized on the large H-ZSM-5 which has been synthesized by using TPABr as SDA. Effects of crystallization conditions and the contents of solutions to synthesized H-ZSM-5 and Silicalite-1 zeolite films have been investigated. Results indicated that: the optimized synthesise conditions of large H-ZSM-5 are crystallizing at 170°C for 7 days and n(SiO₂): n(Al₂O₃): n(TPABr) : n(NH₄): n(H₂O)=100:2:25.3:185:2400. The optimized synthesise conditions of Silicalite-1 zeolite membrane are crystallizing at 180℃for 5h, n(SiO₂): n(TPAOH): n(H₂O)=1:0.34:111.The substrate (H-ZSM-5) pretreated by Ti solution will dramatically enhanced the coverage of Silicalite-1 zeolite film.