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2. PHD Thesis / Tesis PHD
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Title:	The application of TiO2 and ZnO as photocatalyst in concrete for air purification and self cleaning effect
Authors:	Arafa Awadalla Abbas (P39512)
Supervisor:	Muhammad Fauzi Mohd. Zain, Prof. Dr.
Keywords:	Photocatalyst Purification Air -- Purification -- Photocatalysis
Issue Date:	7-Oct-2013
Description:	Indoor air pollution poses a serious threat to human health and environment. Pollutants from exhaust systems can cause unsightly blackening and degradation of walls and building facades. Due to environmental degradation of buildings and the absence of sufficient ventilation to remove pollutants such as volatile organic compounds (VOCs) and tobacco smoke employees complain about increasing sickness such as headache and irritating eyes. Previous studies showed these sicknesses are related to the elevated indoor air pollutant concentration which is known as Sick Building Syndrome. Photocatalytic oxidation (PCO) is a promising technique in controlling the deterioration of buildings and offers a new alternative for air pollutant removal from indoor areas. This study aims to apply photocatalytic materials to the surfaces of concrete block for purifying indoor air and keeping concrete clean. To meet this goal, two methods of application for titanium dioxide (TiO2), zinc oxide (ZnO), and their mixture (TiO2+ZnO) to concrete blocks were carried out. First of these methods was by mixing the TiO2, ZnO, and TiO2+ ZnO with the surface layer of concrete block and the second by coating (1 mm) thin layer of these catalysts on the surface of concrete block. Common indoor air pollutants such as benzene, toluene and tobacco smoke were selected as target pollutant compounds in this study. Concrete samples were subjected to the aforementioned pollutants in a home built reactor (chamber) and sensitivity analyses were conducted using GC-gas, GC-FID, GC-MS, and Scanning Electron Microscopy (SEM) to determine the efficiency of the catalyst for adsorption and degradation of VOCs (benzene and toluene) and tobacco smoke. Furthermore, the work was carried out under typical room temperature, atmospheric pressure, irradiation time and ultraviolet (UV) lamp intensities. Results show that the pollutant removal efficiency for VOCs and tobacco smoke is significantly increased for samples using photocatalysts in the coated surface as well as concrete block surface mix with photocatalysts. In addition, concrete blocks coated with the photocatalysts show better performance than the concrete blocks surface mix with photocatalysts. It is also found that the adsorption and degradation rate of the mixture of TiO2+ ZnO was higher and faster than TiO2 or ZnO alone. Actually all catalysts oxidize pollutant into harmless compounds. Scanning Electron microscopy (SEM) analysis results also reveal that the samples are more uniform distribution before adsorption, and much rougher surface is observed after adsorption and the pore size increases with the increase in adsorption. Numerous tests such as Rhodamine B, porosity and durability were conducted for the self-cleaning concrete study. Based on the results obtained from the self-cleaning test, thin layer TiO2+ ZnO coated concrete block surfaces show a higher RhB discoloration performance than TiO2 or ZnO alone, and uncoated samples. The pollutants removal ability of catalyst mixed samples improves when surface porous increases. Since the photocatalytic activity of the concrete surface layers decreases with curing age therefore catalyst painting repairing of the photocatalytic block surfaces could be applied to maintain the pollution removal effect. From this study it could be concluded that the use of photocatalytic concrete blocks meets its objectives via achieving the goal of indoor air purification and the goal of self cleaning concrete.,Ph.D
Pages:	192
Call Number:	TD883.A234 2013 3
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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