- 學位論文
選擇性催化加氫技術還原水中硝酸鹽為氮氣之研究
Selective Catalytic Hydrogenation of Nitrate to Nitrogen on Pd-Cu/TiO2 Catalysts
摘要
利用催化材料對硝酸鹽進行催化加氫降解實驗，已被證實是一可行之處理方式，具有效率高與經濟性等優點。本篇論文之研究重點在於利用不同之材料製備方法及催化加氫系統下降解硝酸鹽，以達到最大的氮氣選擇性。本篇研究選擇三種材料製備方法－光沉積法、熱浸漬法、無電電鍍法－來製備Pd-Cu/TiO2催化材料，並選擇商用Degussa P25二氧化鈦粉末為負載金屬之載體，實驗結果顯示，以光沉積法製備之催化材料具有最均勻的金屬批覆性及最小的金屬顆粒，對於降解硝酸鹽更具有最佳的氮氣選擇性，因此選擇光沉積法為後續實驗中的材料製備方法。為了瞭解催化材料的表面特性及物化特性，本實驗以穿透式電子顯微鏡觀察催化材料表面金屬負載情形，以BET比表面積測定儀測定催化材料之比表面積，以程式升溫還原儀測試表面金屬還原情形，並以傅立葉氏轉換紅外線光譜儀探討反應過程中可能鍵結之汙染物及其中間產物組成，以及利用感應耦合電漿原子發射光譜儀量測金屬之實際負載量。 批次實驗結果顯示，在適當之操作條件下，催化加氫降解硝酸鹽之反應有最佳之氮氣選擇性，同時可將40 mg-N/L之硝酸鹽完全降解，其條件為：(1)以Pd-Cu/TiO2雙金屬負載二氧化鈦為催化材料，其Pd:Cu負載比例為1:1且總金屬批覆量為3 wt.%，並且設定鍛燒溫度200 ℃並通以氫氮混和氣體還原金屬，(2)設定氫氣流量為100 mL/min，(3)控制系統pH值為7。
並列摘要
The catalytic hydrogenation technology applied in the removal of nitrate in water has been proved to be an effective and economical treatment process. Therefore, in this study, the main purpose is to enhance the nitrogen selectivity of nitrate degradation using catalytic hydrogenation method with different prepared catalysts. Three different catalyst preparation method, photodeposition method, thermal impregnation method, and electroless plating method, were employed to the nitrate degradation. The catalyst prepared by photodeposition exhibits the most uniform metal distribution and the highest selectivity of nitrogen. Therefore, titanium (P25) supported palladium-copper bimetallic catalysts (Pd-Cu/TiO2) prepared by photodeposition are applied to the catalytic hydrogenation of nitrate (NO3－) in the liquid phase. The morphologies and the characterization of the prepared catalysts were examined with transmission electron microscopy (TEM), surface area analysis (BET), temperature programming reduction (TPR), and Fourier transform infrared spectrophotometer (FTIR). The optimum operating values of Pd:Cu ratio, total metal content, calcined temperature, hydrogen flow rate, and pH value for maximizing the nitrogen selectivity of catalytic hydrogenation have been determined to be 1:1, 3 wt.%, 200 ℃, 100 ml/min, and 7.