PDF Publication Title:
Text from PDF Page: 005
Figure 3 Surface of platinum-YSZ composite MIEC electrode that has been polished for zeolite membrane application. crystals were grown to develop a technique suitable to this application. Reproducibility was good given care- ful lab technique. The best method found involved pre-cleaning the glassware with tetramethylamonium hydroxide. In a given range of chemistry, the crystallite size was generally constant. The growth process was controlled by an initial nucleation stage, which determines the number of crystals to be produced and a secondary growth phase that determines the final size of crystals grown [14]. In this case, a clear dilute solution tech- nique [15] was chosen as it appeared to be slower to nucleate and more controllable. The processing condi- tions could be varied to produce a final product of the zeolite as small as 20 nm and as large as 500 nm. The uniformity of the distribution was achieved only under the conditions of constant stirring. 3.3.2. Zeolite deposition The zeolites were deposited by creating an aqueous suspension in the concentration range to allow a mono- layer to be produced over the area of a drop placed on the sensor. The work at this stage involved much trial and error since the drop size is related to surface tension between the drop and the sensor surface, and concen- trations are extremely low. For the samples produced, the concentrations were estimated from the area of the sensor and the weight of a drop placed on its surface. The zeolite suspensions are relatively stable given the inherent surface charge associated with zeolites [16]. At the extremely low concentrations used, no notable settling was observed for two to three days. The key to this process was a controlled drying process. The probability of success was high if a low concentration was used in conjunction with a long settling period and slow drying. The technique was developed as a replacement for the dip coating/Langmuir Blodgett films produced by Boudreau and Tsapatsis [17]. This technique requires minimal equipment and produces suitable results. The films which were going to be regrown later could not be observed under an SEM, since the zeolites require gold coating for SEM observation, which would interfere CHEMICAL SENSORS 4311PDF Image | Development of a selective gas sensor utilizing zeolite membrane
PDF Search Title:
Development of a selective gas sensor utilizing zeolite membraneOriginal File Name Searched:
2003-79-J-Mat-Sci-Rauch.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)