| 摘要: | 電-芬頓程序(electro-Fenton)屬於高級氧化程序之一種，主要原理是利用電流將經過Fenton程序產生的三價鐵離子在陰極快速還原，再次參與Fenton反應，產生氫氧自由基氧化有機物質。研究中選擇電-芬頓與類-芬頓氧化程序處理2,6-二甲基苯胺，去除污染物，以利實際應用時可以作為參考依據。
主要研究項目包括：
(一) 進行直接電解氧化試驗，以釐清電流對污染物氧化分解之貢獻程度。
(二) 比較電-芬頓與類-芬頓程序氧化2,6-二甲基苯胺之相異性。
(三) 比較電-芬頓氧化期間不同操作因子對2,6-二甲基苯胺去除率之影響情
形，其中各項操作因子包括起始pH、三價鐵離子、電流及過氧化氫添
加濃度等操作參數以作為後續之相關研究基礎。
研究結果顯示，在電-芬頓與類-芬頓反應程序對污染物去除效率之影響情形，電流確實可有效增進2,6-二甲基苯胺對於類-芬頓系統氧化分解污染物之速率。在電流效率操作參數方面，在起始三價鐵離子濃度為0.1 × 10-3 M ~ 2.0 × 10-3 M的範圍中，隨著起始三價鐵離子濃度增加還原成的亞鐵離子也增加。在起始電流為0.5 ~ 5.0 A的範圍中，亞鐵濃度隨電流的上升而增加,但當起始電流上升至5 A時，亞鐵離子濃度反而下降，此結果顯示，增加過多的電流，會造成水的電解而使電流效率降低，增加了電源的消耗，也降低了污染物之去除效率。在起始pH為1.5 ~ 2.0的範圍中，亞鐵離子濃度隨pH的上升而增加，但當pH值上升到3時，系統中亞鐵離子極容易與氫氧根形成氫氧化鐵沉澱，使得系統亞鐵離子濃度下降。
綜合研究結果可得，2,6-二甲基苯胺在起始pH=2.0, [Fe3+]=1 × 10-3 M, [H2O2]=20 × 10-3 M與1 A電流下可得最佳處理效果。
Electro-Fenton process is one of advanced oxidation processes. This method applies H2O2 and ferrous ions to produce hydroxyl radical for oxidizing the contaminants.In this study,I choose electro-Fenton and Fenton-like processes to treat 2,6-dimethylaniline.
The objectives of this study included：(1) to identify the ability of direct electrolysis in oxidizing pollutant; (2) to compare the oxidation efficiency of the electro-Fenton and Fenton-like processes; (3) to determine the influences of initial pH,ferric ion,current and hydrogen peroxide concentration on the oxidation of 2,6-dimethylaniline.
Results show that oxidation efficiency of the electro-Fenton process is better than Fenton process.Increasing the ferric concentration and electric current will enhance the oxidation efficiency.When the electric current is increased to 5 A,the ferrous concentration decreased.Too much electric current will result in water electrolysis and reduce the current efficiency of ferric reduction and
the refore increased power cost.Increasing the initial pH from 1.5 to 2.0,the ferrous concentration is increased.When the initial pH is increased to 3.0,the ferrous easily reacted with hydroxide and changed to become iron oxide and thus the ferrous concentration is decreased. The optimum experiment condition for electro-Fenton process were controlled as follows:
[2,6-DMA]=1×10-3 M , [Fe3+]=1×10-3 M, [H2O2]=20×10-3 M, initial pH=2.0, current=1 A. |
