426673 Mild Detemplation of Sub-Micron Silicalite-1 Membranes for Xylene and Butane Isomer Separation

Wednesday, November 11, 2015: 4:45 PM
155D (Salt Palace Convention Center)
Han Zhang, Christopher W. Macosko and Michael Tsapatsis, Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN

Conventional thermal detemplation of zeolite membranes with high temperatures at ~500 °C usually leads to defects or cracks due to the mismatched thermal expansions between zeolite membrane and substrate. Also, high temperature detemplation methods preclude the application of temperature-sensitive substrates such as polymer supports. In addition, the energy cost of thermal detemplation can limit industrial application. Here, we fabricated sub-micron silicalite-1 membranes supported on porous silica and used them as model membranes to evaluate two mild detemplation methods: (i) low temperature thermal and (ii) UV/ozone treatment. The silicalite-1 membranes were fabricated with exfoliated nanosheets as the seed layer followed by gel-free secondary growth, which led to sub-micron b-oriented silicalite-1 membranes on the porous silica supports made by quartz fibers. Xylene and butane isomer permeation tests demonstrated that thermal treatment at a nominal oven temperature as low as 280 °C for 8 hours or UV/ozone treatment for 6 hours is sufficient to establish high selectivity. The highest temperature during the UV/ozone treatment was around 80 °C. The implications of these findings to membranes supported on flat porous polymer sheets or polymer hollow fibers will be discussed.

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See more of this Session: Membrane Formation
See more of this Group/Topical: Separations Division