Full metadata record
DC FieldValueLanguage
dc.contributorFaculty of Construction and Environmenten_US
dc.contributor.advisorLee, S. C. (CEE)-
dc.creatorZhang, Zhuozhi-
dc.identifier.urihttps://theses.lib.polyu.edu.hk/handle/200/9056-
dc.languageEnglishen_US
dc.publisherHong Kong Polytechnic University-
dc.rightsAll rights reserveden_US
dc.titleCombination of adsorption and catalytic oxidation on removal of formaldehyde in low concentrationen_US
dcterms.abstractCobalt oxide impregnated activated charcoal were synthesized using wet impregnation method in this thesis, in order to realize the combination of adsorption and catalytic oxidation for removal of low concentration gas phase formaldehyde. Compared with the previous studies reviewed in the literature review section (treating with formaldehyde concentration over 100 ppm commonly, with reaction temperature higher than 70℃ in most cases), the impregnated charcoal materials showed good performance for low concentration formaldehyde (influent concentration of 175 ppb) under room temperature. In regard to the material characterization, impregnation of cobalt oxides has negative effects on the porous structure and the surface morphologies of the activated charcoal, according to the material characterization. Cobalt oxides precipitated outside the charcoal particles were observed, in which CoO and Co3O4 precipitation were identified by X-Ray Diffraction analysis, especially on the 15% Co/AC sample. In the study of effects of reaction temperature, a performance order of 25℃ > 45℃ > 35℃ was observed. It is concluded that lower temperature was suitable for formaldehyde adsorption, while higher temperature enhanced the catalytic oxidation. Desorption was observed on the higher temperature conditions, and saturation was also observed on raw activated charcoal in the long-term tests, indicating that the raw activated charcoal might not be suitable for long-term usage under relatively high temperature environment. Improvements were observed as the ozone is induced into the reaction in the study of effects of ozone concentration, especially on the cobalt oxide impregnated samples (approximately 4~5% increment with 14 ppb ozone input, and about 10% increment with 27 ppb ozone input were obtained). Different reaction mechanisms were proposed for reaction scenarios of no ozone input and with ozone input, since enhancement was also observed in the samples with no ozone input. In conclusion, optimum cobalt content weight-based ratio on the activated charcoal should be between 2% to 5% according to the formaldehyde removal tests. And under room temperature with low ozone input (approximately 15 ppb), the material showed good formaldehyde removal efficiency.en_US
dcterms.extentxiv, 61 pages : color illustrationsen_US
dcterms.isPartOfPolyU Electronic Thesesen_US
dcterms.issued2016en_US
dcterms.educationalLevelM.Sc.en_US
dcterms.educationalLevelAll Masteren_US
dcterms.LCSHHong Kong Polytechnic University -- Dissertationsen_US
dcterms.LCSHFormaldehyde -- Absorption and adsorptionen_US
dcterms.LCSHFormaldehyde -- Oxidationen_US
dcterms.accessRightsrestricted accessen_US

Files in This Item:
File Description SizeFormat 
991021952832303411.pdfFor All Users (off-campus access for PolyU Staff & Students only)9.52 MBAdobe PDFView/Open


Copyright Undertaking

As a bona fide Library user, I declare that:

  1. I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
  2. I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
  3. I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.

By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.

Show simple item record

Please use this identifier to cite or link to this item: https://theses.lib.polyu.edu.hk/handle/200/9056