| 摘要: | 本研究以 Fenton-like 試劑處理水溶液中之丙烯腈，控制pH值、過氧化氫、三價鐵
離子加藥量，利用高效能液相層析儀、總碳分析儀、離子層析儀及凱氏氮分析方法等，評
估Fenton-like 程序對丙烯腈及總溶解性有機碳之去除效率，並探討含氮副產物、
亞硝酸根離子及硝酸根離子生成與消長之變化。
實驗結果顯示，在初始pH 為2.5 時丙烯腈之去除率為100%，但在pH 3 時， 丙烯
33096;之去除效果在60分鐘內尚無法分解完全，丙烯腈及總溶解性有機碳之去除率
均隨三價鐵離子及過氧化氫添加量之增加而增加，其去除率最高分別 可達100 %及55 %。
當系統中之丙烯腈被Fenton-like試劑分解後，除了碳基會被礦化外，氮基也會被氧
化，氮基被氧化後除形成有機氮化物外，並反應釋出亞硝酸根離子與硝酸根離子，當過氧
化氫與三價鐵離子之初始加藥量提高，亞硝酸根離子與硝酸根離子產量也隨之上升。亞硝
酸根離子釋出後，有先上升再下降之趨勢，氨氮亦有相似之趨勢，硝酸根濃度則呈現先上
升而後持平的現象。Fenton-like處理丙烯腈水溶液實驗過程中有大量氣體產生，經
氮之質量平衡後，發現氮氣佔原丙烯腈中總氮量之90〜94%，顯示其脫氮效果
良好。依理想氣體方程式換算後，可得知在本研究之Fenton-like系統反應一小時後，會
在40〜44 mL之氮氣生成。
本系統中，過氧化氫之消耗動力，符合擬一階動力學方程式，其反應速率常數kobs,H2O2值
隨著過氧化氫之加藥量增加而增大，惟劑量增至6000 mg/L時，反應速率常數kobs,H2O2值
因過氧化氫在本系統中之殘留累積而變小，另外，其kobs,H2O2值隨著三價鐵離子之加藥量
增加而下降。在總溶解性有機碳之降解動力方面，其反應速率常數kobs,DOC值隨著過氧化
氫之加藥量增加而有先下降後上升之趨勢，並從實驗中發現，過氧化氫之初始加藥量對
Fenton-like系統之有機碳之分解速率影響較小，而隨著三價鐵離子之加藥量增加，其
kobs,DOC值亦會隨之上升。
This research was to evaluate the treatment efficiency and formation of
nitrogen-containing compounds from Fenton-like reaction of acrylonitrile (AN)
in aqueous solution. HPLC, TC, IC and TKN were used for the evaluation.The
effects of pH value of solution, initial concentration of hydrogen peroxide
and ferric ions were examined. The efficiency of Fenton-like process was
measured by the decomposition of acrylonitrile, removal of dissolved organic
carbon (DOC). In addition, formation and variation of organic nitrogen,
ammonia nitrogen, nitrite and nitrate ions during the reaction were also
detected in this study.
In general, it is an effective method to remove acrylonitrile from the
aqueous solution using Fenton-like method. In this study, after 60 minutes
Fenton-like process treatment, the decomposition of acrylonitrile at the
condition of pH 2.5 was above 100%. On the other hand, acrylonitrile could not
be decomposed completely at pH 3. The result also showed that the removal
efficiencies of AN and DOC increased with increasing of hydrogen peroxide. The
same phenomenon was observed when the hydrogen peroxide concentration was
varied. The highest removal efficiency of 100% and 55% for AN and DOC,
respectively, was obtained in this study.
On the study of nitrogen mass balance, immediately after the Fenton-like
reagent addition, NO2－ rose rapidly up to a peak and followed by a slow
decline. The similar phenomenon of NH4+ was observed in this study. The
concentration of NO3－ increased with reaction time and then remained
approximately constant. Formation of NO2－ and NO3－ increased with increasing
of Fenton-like reagent dosage. Visible gas evolution from the reaction vessels
suggested gaseous byproducts. Nitrogen gas yields were calculated from the
nitrogen balance results. Nitrogen gas production accounted for about 90
12316;94% of nitrogen in AN. The ideal-gas law was used to calculate the
volume of nitrogen gas. The results showed that 40〜44mL of nitrogen gas
was produced during 1 hour Fenton-like reaction.
The kinetic of the decompositions of hydrogen peroxide and DOC followed the
pseudo-first order reaction, and the highest observed reaction constant value
of 0.070 min-1 and 0.096 min-1, respectively, was obtained in this study. |
