Electroding Methods for in situ Reverse Osmosis Sensors

dc.contributor.authorDetrich, Kahlilen
dc.contributor.committeechairGoulbourne, Nakhiah C.en
dc.contributor.committeememberInman, Daniel J.en
dc.contributor.committeememberVlachos, Pavlos P.en
dc.contributor.departmentMechanical Engineeringen
dc.date.accessioned2014-03-14T20:31:42Zen
dc.date.adate2010-03-19en
dc.date.available2014-03-14T20:31:42Zen
dc.date.issued2010-01-28en
dc.date.rdate2010-03-19en
dc.date.sdate2010-02-11en
dc.description.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.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-02112010-081846en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-02112010-081846/en
dc.identifier.urihttp://hdl.handle.net/10919/31207en
dc.publisherVirginia Techen
dc.relation.haspartDetrich_KTE_T_2010.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectin situ sensingen
dc.subjectreverse osmosis membraneen
dc.subjectplatinized polymer graften
dc.subjectfoulingen
dc.subjectelectrical impedance spectroscopyen
dc.titleElectroding Methods for in situ Reverse Osmosis Sensorsen
dc.typeThesisen
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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