Microwave- Induced Photo-Degradation of Chlorobenzene Using TiO2 Coated on Cordierite

• Main Authors: Yi-ling Yeh, 葉怡伶
• Other Authors: Chih-Ju Jou
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/54753573226696700155

碩士 === 國立高雄第一科技大學 === 環境與安全衛生工程所 === 98 === In this research, TiO2 was prepared using the sol-gel processing method and then spread on the surface of cordierite crystal particles to be used as a catalyst for decomposing chlorobenzene under microwave irradiation. The microwave irradiation enhances the production of OH- free radicals by TiO2, inhibit the recombination of electrons and electron holes, and improve the efficiency of organic matter decomposition. Raising the microwave power level or increasing the TiO2 quantity will lead to more removal of chlorobenzene. However, when the TiO2 dosage exceeds 1 g/mL, the chlorobenzene removal efficiency is adversely affected because too much TiO2 suspended in the solution will block and/or disperse the microwave radiation thus deteriorating the photo-degradation efficiency. Laboratory results indicate that the chlorobenzene removal efficiencies after irradiated with 30W microwave for 300 seconds are 61.7% for commercial P-25 TiO2, 49% for laboratory-prepared TiO2, 43.2% for TiO2-covered cordierite, 20.7% for cordierite, 17.6% for only microwave irradiation. The commercial P-25 TiO2 is in powder form that has different distribution pattern in solution than TiO2 spread on the surface of cordierite; powder TiO2 can be evenly suspended in the solution so that the suspension has different surface of contact from cordierite. When the surface of cordierite is covered with TiO2 crystal with pointed surface, the TiO2 crystal will absorb more microwave energy than cordierite. A larger exposed surface enables more microwave to be absorbed, more surface active sites to be generated, and more OH free radicals to be generated so that the photo-decomposition reaction is greatly enhanced. The TiO2-coated cordierite under microwave irradiation is a novel technology for decomposing chlorobenzene at relatively low temperature.