| 摘要: | 工業製程使用之揮發性有機污染物(VOCs)種類繁多，由於其物化特性易於製造或加工過程中揮發，衍生VOCs逸散問題，甲苯為典型之有機化合物，常被作為設備元件的清潔劑。VOCs不僅存在於各種行業，亦為評估室內空氣品質之重要指標，長期暴露在空氣品質不佳環境，易導致頭暈、乏力及情緒起伏等症狀。本研究以perovskite-type觸媒為基礎，開發新穎之triple perovskite-type觸媒，並探討觸媒製備過程中添加氨水及觸媒表面改質，進一步強化觸媒催化活性之可行性。本研究主軸概分為兩個部分，一為triple perovskite-type觸媒於熱催化系統之應用，另一則是利用觸媒結合臭氧技術進行臭氧催化氧化(ozone catalytic oxidation, OZCO)應用於甲苯去除。結果顯示triple perovskite-type觸媒對甲苯去除具有高活性，尤其是La3MnCuCuO9-NH3 (KMnO4)觸媒，於熱催化系統中(進流濃度為500 ppm)，於250℃對C7H8之轉化率及礦化率分別達100%及83%；於臭氧催化氧化系統中(進流濃度為20 ppm、O3/C7H8=8；室溫)，反應6個小時內維持100%的轉化效率，而礦化率於4個小時內維持高礦化率(100%)，反應測試5個小時後逐漸降低至85%。觸媒的物化特性分析結果顯示La3MnCuNiO9-NH3 (KMnO4)具有較高之比表面積及孔體積，分別為26.74 m2/g及0.16 cm3/g，且具有高比率之吸附氧與Mn4+及多價態之Cu與Ni，增加觸媒的催化活性，進而促進甲苯氧化反應。臭氧催化氧化主要生成之產物為CO2與H2O(g)，其去除機制主要是O3於triple perovskite-type觸媒表面分解為具強氧化能力的活性氧(O*、O2*)，在臭氧催化反應過程中為關鍵物種，配合觸媒之高催化活性，實現室溫條件之甲苯氧化反應，未來於工業廢氣處理及室內空品之應用潛力大。;Various types of volatile organic pollutants (VOCs) are used in industrial processes. Due to their physical and chemical properties, VOCs can easily evaporate during the manufacturing or processing, resulting in fugitive emissions. VOCs are not only present in various industries, but are also important indicators for assessing indoor air quality. Toluene is a typical organic compound that is often used as a cleaning agent for equipment components. Prolonged exposure to poor air quality can lead to symptoms such as dizziness, fatigue, and mood swings. In this study, we developed a novel triple perovskite-type catalyst and investigated the feasibility of adding ammonia and applying catalyst surface modification to further enhance the catalytic activity of the catalysts in the preparation process. The main emphasis of this study includes two parts, one is the application of triple perovskite-type catalyst in thermal catalytic system, and the other is the application of ozone catalytic oxidation (OZCO) for toluene removal using catalyst combined with ozone technology. The results showed that triple perovskite-type catalysts developed were highly active for toluene removal, especially La3MnCuNiO9(n,k) catalyst. In the thermal catalytic system ([C7H8] = 500 ppm), the conversion and mineralization rates of C7H8 at 250°C reached 100% and 83%, respectively. In the ozone catalytic oxidation system ([C7H8] = 20 ppm, O3/C7H8=8; room temperature), the conversion efficiency was maintained at 100% for 6 hours, and the mineralization rate was maintained at a high rate for 4 hours, and gradually decreased to 85% after 5 hours of reaction. The physical and chemical analysis of the catalyst showed that La3MnCuNiO9(n,k) has a high specific surface area and pore volume of 26.74 m2/g and 0.16 cm3/g, respectively. Catalysts with high ratios of Oabs/(Oabs+Olat), Mn4+/(Mn4++Mn3+) and Cu2+ as well as multivalent Ni enhance the catalytic activity which in turn promotes oxidation of toluene. The main products of ozone catalytic oxidation are CO2 and H2O(g), and the removal mechanism is mainly via the decomposition of O3 on the surface of triple perovskite-type catalyst into reactive oxygen species (O*, O2*) with strong oxidizing ability. In the ozone catalytic reaction process, active oxygen generated facilitate the oxidation of toluene at room temperature. The results obtained indicate that this catalyst has great potential for industrial waste gas treatment and indoor air applications. |
