- 學位論文
溶-凝膠/水熱法製備二氧化鈦及其對金黃葡萄球菌殺菌效果之研究
Sol-Hydrothermal Preparation of Titanium Dioxide and its Disinfection Efficiency on Staphylococcus aureus
摘要
本研究以四丁基氧化鈦及醋酸水溶液為起始物，利用溶-凝膠/水熱法(200 ºC，5 小時)及高溫煅燒法(600、700及800 ºC，1小時)製備出不同晶相的二氧化鈦粉末。經塗佈轉鍍於玻璃基板上後，利用對金黃葡萄球菌的殺菌效果，比較不同條件製備所得二氧化鈦的光催化活性，並與商業化的Degussa P-25粉末進行比較。實驗發現二氧化鈦對金黃葡萄球菌的殺菌反應呈現一次動力學模式: log (Nt/N0) = -kt (Nt為照射t時間後的活菌數，N0為起始的活菌數，k為速率常數) ，隨著二氧化鈦熱處理溫度的上升，k值逐漸下降。由於熱處理導致二氧化鈦的相轉換:由銳鈦礦(低溫相)到金紅石相(高溫相)，同時凝聚現象也隨熱處理溫度升高而增加，因此推論二氧化鈦粉體的礦相及比表面積為控制其對金黃葡萄球菌光催化殺菌活性的主要因素。此外，經過乾燥後的二氧化鈦溶凝膠，由於水份的減少使OH基相互縮合鍵結減少，故所得二氧化鈦粉體的粒徑減小，殺菌效果也因此而提高。
並列摘要
Titanium dioxide (TiO2) is extensively used as a photocatalyst due to the strong oxidizing power of its holes, high photostability and redox selectivity. The anatase phase TiO2, in particular, has been greatly studied due to its high photocatalytic activity for the decomposition of various organic pollutants in the environment and the disinfection of microorganisms. In this work, nanometer-sized TiO2 was synthesized using Ti[O(C4H9)]4 as a precursor of TiO2 and acetic acid (CH3COOH) as a peptizer. The initial sol was hydrothermally treated at 200 ºC for 5 h, followed by calcination for 1 h at three different temperatures (600、700 and 800 ºC). The as-prepared TiO2 samples were coated on to glass substrates and evaluated for their bactericidal ability against Staphylococcus aureus. The commercial Degussa P-25 was included in the study for comparison. The death rate of S. aureus was found to follow the first order kinetics: log (Nt/N0) = -kt (Nt: the number of viable cells at time t, N0: the initial cell counts, k: rate constant), and the rate constant k decreased with increasing calcination temperature. The results show strong correlation between the hydrothermal treatment conditions and the properties of the resulting TiO2 particles, such as structure evolution and particle size of the TiO2 samples and their germicidal activity. High calcination temperature resulted in aggregation, as well as phase transformation from anatase to rutile. By drying the initial sol prior to the calcination step, the hydroxyl groups on the TiO2 surface were greatly reduced, resulting in less aggregation and smaller particle size of the resultant TiO2. The bactericidal activity was also improved. Therefore, it is concluded that the anatase phase and surface area are two dominate factors that control the disinfection activity of TiO2 under the given experimental conditions.