Jelan Kuhn

Selective sensor utilizing a thin monolayer of b-oriented silicalite-1 crystals–magneto-elastic ribbon assembly

This report presents the development of new selective gas sensors utilizing a b-oriented silicalite-1 layer-magneto-elastic ribbon assembly. The key principle for the operation of these sensors is monitoring the changes in the resonance frequency of the Metglas strip in relation to the concentration of a component in the gas phase. This technique provides a simple way for monitoring the effects of the amount of adsorbed gases in the silicalite-1 coating. The thickness of the zeolite layer is that of a single crystal. The silicalite-1 crystals are oriented in the b-direction, meaning that the straight channels are perpendicular to the sensor surface, which is confirmed by X-ray diffraction (XRD) analysis. The sensor was able to repeatedly sense carbon dioxide in air and could discriminate between linear and branched hydrocarbons. The sensor was able to detect n-butane, while it did not respond to the presence of iso-butane, indicating sensing selectivity.

Investigating mass transport in zeolite pores by tuning the framework polarity

The polarity of a zeolite is an important parameter determining the transport and separation properties in zeolite packed beds and membranes. This study focuses on the systematic investigation of the zeolite polarity for membrane applications by varying the amount of silanol groups within the framework of silicalite-1. The permeation of water through modified silicalite as well as normal silicalite-1 membranes is measured. The preliminary results show an optimum in the water flux when plotted against the amount of silanol groups.