奈米二氧化鈦覆載於銀擔體之複合物光觸媒對丙酮去除處理之研究

Abstract

目前奈米二氧化鈦光觸媒應用已相當廣泛，但奈米粉體之間因為容易發生團聚的現象，而降低奈米二氧化鈦的效能。由於奈米粉體分散的好壞為影響奈米粉體效能的主要因子之ㄧ，為了改善奈米粉體團聚的問題，一般是藉由添加界面活性劑使奈米粉體能均勻分散，但界面活性劑多為有機物，在光照射下容易發生劣化現象，造成奈米粉體品質降低，因此本實驗藉由調整製備溶液的酸鹼度改變顆粒表面電性，利用不同顆粒其本身的表面電性差異特性，使二氧化鈦與銀有良好的結合及分散性。實驗結果顯示將配製溶液控制在pH5.8的中性條件下，TiO2與藥品級Ag恰為介達電位差異最大時，可獲得有高分散性之TiO2/Ag複合物光觸媒。本研究以丙酮當作汙染物測試標的，以連續式反應器進行實驗測試之結果亦顯示，在TiO2、Ag顆粒表面電性相異環境製備下，所製備的高分散性TiO2/Ag複合物光觸媒有極佳的丙酮去除效率。

Titanium dioxide has been extensively used as photocatalyst in nowadays. But aggregation between nanoparticles results in a lower photoactivity. Generally, surfactants are added to make nanoparticles disperse well. However, surfactants belong to organic matters, it could be decomposed by illumination of sunlight or UV lamp. This study focuses on the relationship between pH status and surface charges of particles, and attempt to synthesize well-bonding composites by means of different surface charges between TiO2 and Ag carrier. The experiments showed that TiO2 can’t adsorb on the surface of Ag carrier in both acidic and alkaline solution due to the same surface charges. A highly-dispersed TiO2/Ag composites are obtained in a neutral solution (pH5.8) where zeta potential of TiO2 and Ag carrier is +27, -10mV, respectively. Strong electric attraction between TiO2 and Ag carrier in neutral solution spontaneously results in a highly-dispersed TiO2/Ag composite, and it is found excellent for the removal of acetone due to chemical binding Ti-O-Ag.