| 摘要: | 本研究以紫外光/過氧化氫程序處理辛基苯酚聚氧乙烯醇(Octylphenol polyethoxylates, OPEOn)水溶液，並探討溶液pH、反應物初始濃度、光輻射強度及過氧化氫添加量等操作因子對處理效果之影響，以及，探討OPEOn於紫外光/過氧化氫程序可能之降解途徑，最後，評估環境中常見之無機陰離子對降解程序之影響。 實驗結果顯示，3小時反應時間內，直接光解和H2O2直接氧化均無法有效去除溶液中OPEOn，而UV/H2O2程序可在反應90分鐘後，達到90%以上之去除率，但無法有效去除水中總有機碳含量，原因是UV/H2O2程序僅能破壞OPEOn原本的結構，而無法進一步將其礦化成二氧化碳和水。 溶液中碳酸鹽和硝酸鹽的存在，均會顯著降低OPEOn的降解速率，這是因為兩者均可捕捉系統內的氫氧自由基所致。此外，碳酸鹽對程序之影響和其濃度無關，而硝酸鹽對程序之影響則和其存在的濃度有關聯。 由LC/MS分析中間產物之結果顯示，OPEOn降解由聚乙氧基鏈開始，而後氫氧自由基可能會添加至芳香環上，或是取代烷基上的氫，以及削減烷基鏈。降解過程中所生成之中間產物，包括：短鏈烷基苯酚聚氧乙烯醇、醛類化合物以及有機酸等。 本研究初步認為，以UV/H2O2程序降解OPEOn，其最適操作條件為：光強度=0.89 W/L，pH=7，H2O2/OPEOn=10。此操作條件下，反應90分鐘後，OPEOn可達95%去除率及15%之礦化效果。 This study evaluates the treatment of octylphenol polyethoxylates (OPEOn) solution using UV/H2O2 process. The influences of pH, initial substrate concentration, H2O2 dosage and photon fluence rate in OPEOn degradation were studied. Also, possible degradation mechanism of OPEOn in UV/H2O2 process was proposed. Finally, assess the effect of inorganic salts, such as NaNO3 and Na2CO3, on OPEOn degradation. Relatively slow OPEOn degradation was observed during UV radiation, while OPEOn was not oxidized by H2O2 along. Combined UV/H2O2 could effectively degraded OPEOn, and resulted in more than 90% removal of OPEOn in 90 min period. However, removal of total organic carbon in solution was ineffective. The results indicated that OPEOn was destroyed and formation numerous of intermediate products, but can’t converted to CO2 and H2O by mineralization. The presence of NaNO3 and Na2CO3 in solution led to decreased the degradation rate of OPEOn. This may be attributed to the scavenging of hydroxyl radical by these two inorganic anions. Besides, the effect of NaNO3 was depend on the concentration of anion. The degradation products were analyzed by LC/MS, and revealed that OPEOn degradation begin from shortening the ethoxy chain. And the following may be cleavage of the alkyl chain, or substitution of the hydrogen on alkyl chain with hydroxyl radical, as well as addition hydroxyl radical to the aromatic ring. The degradation intermediates are short chain ethoxylated phenol, aldehydic compounds and organic acid. In summary, the optimum operating conditions for UV/H2O2 process to destroy OPEOn found in this study was as follows：UV light intensity = 0.89 W/L, pH=7, H2O2/OPEOn molar ratio = 10. In which, a treatment effectiveness of 95% was achieved after 90 minutes of reaction time, and 15% mineralization was obtained . |
