Assessing Photocatalytic Oxidation Using Modified TiO2 Nanomaterials for Virus Inactivation in Drinking Water: Mechanisms and Application

dc.contributor.advisorLi, Qilinen_US
dc.contributor.committeeMemberAlvarez, Pedro J.en_US
dc.contributor.committeeMemberBarron, Andrew R.en_US
dc.contributor.committeeMemberTao, Yizhi Janeen_US
dc.creatorLiga, Michaelen_US
dc.date.accessioned2013-06-05T15:01:01Zen_US
dc.date.accessioned2013-06-05T15:01:10Zen_US
dc.date.available2013-06-05T15:01:01Zen_US
dc.date.available2013-06-05T15:01:10Zen_US
dc.date.created2012-12en_US
dc.date.issued2013-06-05en_US
dc.date.submittedDecember 2012en_US
dc.date.updated2013-06-05T15:01:10Zen_US
dc.description.abstractPhotocatalytic oxidation is an alternative water treatment method under consideration for disinfecting water. Chlorine disinfection can form harmful byproducts, and some viruses (e.g. adenoviruses) are resistant to other alternative disinfection methods. Photocatalytic oxidation using nano-sized photocatalytic particles (e.g. TiO2, fullerene) holds promise; however, it is limited by its low efficiency and long required treatment times. This research focuses on improving virus inactivation by photocatalytic oxidation by modifying catalysts for improved activity, by analyzing virus inactivation kinetics, and by elucidating the inactivation mechanisms of adenovirus serotype 2 (AdV2) and bacteriophage MS2. Modifying TiO2 with silver (nAg/TiO2) or silica (SiO2-TiO2) improves the inactivation kinetics of bacteriophage MS2 by a factor of 3-10. nAg/ TiO2 increases hydroxyl radical (HO•) production while SiO2 increases the adsorption of MS2 to TiO2. These results suggest that modifying the photocatalyst surface to increase contaminant adsorption is an important improvement strategy along with increasing HO• production. The inactivation kinetics of AdV2 by P25 TiO2 is much slower than the MS2 inactivation kinetics and displays a strong shoulder, which is not present in the MS2 kinetics. nAg/TiO2 initially improves the inactivation rate of AdV2. SiO2-TiO2 reduces the AdV2 inactivation kinetics since adsorption is not significantly enhanced, as it is with MS2. Amino-C60 is highly effective for AdV2 inactivation under visible light irradiation, making it a good material for use in solar disinfection systems. The efficacy of amino-fullerene also demonstrates that singlet oxygen is effective for AdV2 inactivation. When exposed to irradiated TiO2, AdV2 hexon proteins are heavily damaged resulting in the release of DNA. DNA damage is also present but may occur after capsids break. With MS2, the host interaction protein is rapidly damaged, but not the coat protein. The kinetics of MS2 inactivation are rapid since it may quickly lose its ability to attach to host cells, while AdV2 kinetics are slower since the entire capsid must undergo heavy oxidation before inactivation occurs. Adenovirus inactivation likely occurs through breaching the capsid followed by radical attack of DNA and core proteins.en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.citationLiga, Michael. "Assessing Photocatalytic Oxidation Using Modified TiO2 Nanomaterials for Virus Inactivation in Drinking Water: Mechanisms and Application." (2013) Diss., Rice University. <a href="https://hdl.handle.net/1911/71288">https://hdl.handle.net/1911/71288</a>.en_US
dc.identifier.slug123456789/ETD-2012-12-330en_US
dc.identifier.urihttps://hdl.handle.net/1911/71288en_US
dc.language.isoengen_US
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.subjectTiO2en_US
dc.subjectAdenovirusen_US
dc.subjectVirusen_US
dc.subjectPhotocatalytic oxidationen_US
dc.subjectWater disinfectionen_US
dc.subjectNanotechnologyen_US
dc.titleAssessing Photocatalytic Oxidation Using Modified TiO2 Nanomaterials for Virus Inactivation in Drinking Water: Mechanisms and Applicationen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentCivil and Environmental Engineeringen_US
thesis.degree.disciplineEngineeringen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
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