Zsm-5 Zeolite Membranes Without Organic Template Agent Was Prepared

Zeolite membranes have great potential applications in the separation and membrane reactors because of their unique characteristics such as their chemical and structural properties and excellent separate trait specially. Among different Zeolites, more focus has been drawn on the synthesis of MFI(ZSM-5 or Silicalite-1) membranes, because of the pore system of this zeolite (straight, circular, pores(0.54x0.56nm) running perpendicular to sinusoidal, elliptical pores(0.51x0.54nm)), suitable for separation of several industrial important organic molecules and the relatively large amount of information available for its synthesis . The method of ZSM-5 zeolite membranes preparation has several problems because of the existed organic template, so the main works of this thesis focused on the new method of ZSM-5 zeolite membranes preparation by the seeded method and the varying-concentration synthesis with organic-free template.1. Nanosized ZSM-5 zeolite applied on the seeded method as the surface crystal-seed was synthesized without organic template by hydrothermal method. The influence of the synthesized process on the crystal quality such as the compound of the solution, crystal temperature and time, ageing time et al were studied thoroughly. It was reported that the nanosized was synthesized successfully, and the granularity of the crystal was 15nm. The experiment that the zeolite was applied as the surface crystal-seed on the outer surface of porous α -AI2O3 tubular acquired the success.2. It was studied that the ZSM-5 zeolite membranes grown fully was impacted on by varying-concentration synthesized method with organic-free template. A new method of preparing ZSM-5 zeolite membranes on the outer surface of porous α -AI2O3 tubular by coating 15nm ZSM-5 seeds without organic templates and then by varying-concentration synthesis from thick to thin with organic-free template sol-gel was investigated. The advantage of the method focused on the twice synthesis, short time (24 hour), thin and dense membranes. The permeation flux of H2 was 8.0 X10~-7mol/(m2sPa) in the normal temperature; the ideal selectivity of membrane for H2/N2 was 2.9 . The formation course of zeolite membranes was discussed in the condition of the synthesized technics.