Removal of formaldehyde from indoor air : enhancing surface-mediated reactions on activated carbon

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dc.contributor.advisorKatz, Lynn E.
dc.contributor.advisorSpeitel, Gerald E.
dc.creatorCarter, Ellison Milneen
dc.date.accessioned2014-09-22T20:46:48Zen
dc.date.accessioned2018-01-22T22:26:35Z
dc.date.available2018-01-22T22:26:35Z
dc.date.issued2013-08en
dc.date.submittedAugust 2013en
dc.date.updated2014-09-22T20:46:49Zen
dc.descriptiontexten
dc.description.abstractFormaldehyde is a ubiquitous and hazardous indoor air pollutant and reducing concentrations in indoor environments is a public health priority. The goals of this doctoral work were to advance analytical methods for continuous monitoring of formaldehyde at very low concentrations (sub-20 ppb[subscript v]) and to improve fundamental, mechanistic understanding of how structural and chemical properties of activated carbon influence removal of formaldehyde from indoor environments. To achieve these goals, emerging sensor-based technology was evaluated for its ability to detect and quantify ppb[subscript v]-level formaldehyde concentrations on a continuous basis at relative humidity levels characteristic of residential indoor environments. Also, a combination of spectroscopic and selective titration techniques was employed to characterize molecular-level structural and chemical properties of traditional and chemically treated granular activated carbon (GAC). In addition to selecting two different commercially available GACs for study, design and preparation of a laboratory-prepared, chemically treated GAC was pursued to create nitrogen-doped GAC with desirable surface chemical properties. Performance of all GACs was evaluated with respect to formaldehyde removal through a series of packed bed column studies. With respect to continuous formaldehyde monitoring, a method detection limit for emerging sensor technology was determined to be approximately 2 ppb[subscript v], and for relative humidity levels characteristic of indoor environments (> 40%), quantitative, continuous formaldehyde measurements less than 10 ppb[subscript v] were robust. The two commercially available GACs tested were both capable of removing formaldehyde; however, the GAC with greater density of basic surface functional groups and greater electron-donating potential (Centaur) removed twice as much formaldehyde (on a GAC mass basis) as the less basic GAC (BPL). A laboratory-prepared GAC (BPL-N) was successfully created to contain pyridinic and pyrrolic nitrogen, which was associated with increased surface density of basic functional groups, as well as with increased electron-donating potential. BPL-N exhibited better removal capacity for formaldehyde than BPL and Centaur. Furthermore, packed bed column studies of BPL-N and BPL formaldehyde removal performance yielded evidence to support the hypothesis that electron-donating potential, especially nitrogen functional groups at the BPL-N surface, promote catalytic removal of gas-phase formaldehyde via oxidation.en
dc.description.departmentCivil, Architectural, and Environmental Engineeringen
dc.format.mimetypeapplication/pdfen
dc.identifier.urihttp://hdl.handle.net/2152/26091en
dc.subjectSurface chemistryen
dc.subjectNitrogen dopingen
dc.subjectFormaldehydeen
dc.subjectActivated carbonen
dc.subjectPollutant control technologyen
dc.subjectIndoor airen
dc.titleRemoval of formaldehyde from indoor air : enhancing surface-mediated reactions on activated carbonen
dc.typeThesisen

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