Design and fabrication of zeolite-based microreactors and membrane microseparators

This paper demonstrates that zeolites (i.e., Sil-1, ZSM-5 and TS-1) can be employed as catalysts, membrane or structural materials in miniature chemic al devices. Traditional semiconductor fabrication technology was employed i n micromachining the device architecture. The fabricated miniature zeolite- based structures find applications as catalytic microreactors and membrane microseparators. Four strategies for the manufacture of zeolite catalytic m icroreactors were discussed: zeolite powder coating, uniform zeolite film g rowth, localized zeolite growth, and etching of zeolite-silicon composite f ilm. These zeolites were deposited either as film or discrete islands with controlled particle size, crystal morphology, layer thickness (3-16 mum) an d film orientation (e.g., highly oriented (101) and (200) films). Crystal i ntergrowth was also manipulated through the use of growth inhibitors. Silic alite-l was also prepared as free-standing membrane for zeolite membrane mi croseparators. (C) 2001 Elsevier Science B.V. All rights reserved.