Type of Document Master's Thesis Author Detrich, Kahlil URN etd-02112010-081846 Title Electroding Methods for in situ Reverse Osmosis Sensors Degree Master of Science Department Mechanical Engineering Advisory Committee
Advisor Name Title Goulbourne, Nakhiah C. Committee Chair Inman, Daniel J. Committee Member Vlachos, Pavlos P. Committee Member Keywords
- in situ sensing
- reverse osmosis membrane
- platinized polymer graft
- electrical impedance spectroscopy
Date of Defense 2010-01-28 Availability unrestricted AbstractThe purpose of this work is to develop and evaluate electroding methods for a reverse osmosis (RO) membrane that results in an in situ sensor able to detect RO membrane protein fouling. Four electroding techniques were explored: i) gold exchange-reduction, ii) encapsulated carbon grease, iii) “direct assembly process” (DAP), and iv) platinized polymer graft. The novel platinized polymer graft method involves chemically modifying the RO membrane surface to facilitate platinization based on the hypothesis that deposition of foulant on the platinized surface will affect platinum/foulant/solution interfacial regions, thus sensor impedance. Platinized polymer graft sensors were shown to be sensitive to protein fouling.
Electrodes were characterized by their electrical properties, SEM and XPS. Assembled sensors were evaluated for sensitivity to electrolyte concentration and protein fouling. Micrographs showed coating layers and pre-soak solution influence gold exchange-reduction electrode formation. High surface resistance makes gold exchange-reduction an unsuitable method. Concentration sensitivity experiments showed carbon grease and DAP electroding methods produce unusable sensors. Carbon grease sensors have time-dependent impedance response due to electrolyte diffusion within the micro-porous polysulfone support. DAP electroded sensors proved quite fragile upon hydration; their impedance response is transient and lacks predictable trends with changes in concentration. A parametric study of the platinized polymer graft method shows amount of grafted monomer correlates to grafting time, and deposited platinum is a function of exchange-reduction repetitions and amount of grafted monomer. Platinized polymer graft sensors were fouled in both dead-end and cross-flow RO systems, and their impedance trends, while varying between sensors, indicate protein-fouling sensitivity.
Filename Size Approximate Download Time (Hours:Minutes:Seconds)
28.8 Modem 56K Modem ISDN (64 Kb) ISDN (128 Kb) Higher-speed Access Detrich_KTE_T_2010.pdf 2.97 Mb 00:13:45 00:07:04 00:06:11 00:03:05 00:00:15
If you have questions or technical problems, please Contact DLA.