Thermal transpiration
In collaboration with EPFL, we have developed a silica based aerogel Knudsen Pump prototype by combining a low temperature co-fired ceramic technology and sodium silicate based aerogels. A temperature difference applied by resistive heating of the ceramic substrate and a flow rate density ~38 µl min-1 mm-2 was reached. A comparison with other Knudsen pump membranes shows outstanding performance [1].
Recently, based on a breakthrough 3D printing technology, our group was able to print a prototype membranes with a top-layer containing manganese oxide nanoflakes. The MnO2 serves as a dual-functional light absorbers for the efficient photo-thermal conversion to reach a pumping flow rate of 20 µl min-1 mm-2, and in addition, the catalytic degradation of VOCs [2]. Furthermore, the processing, pore formation and properties (pumping and catalysis) correlations in an aerogel Knudsen Pump system were explored, and various aerogel materials with complementary properties have been developed [3].
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