氫氧自由基對臭氧反應影響之探討

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Title:	氫氧自由基對臭氧反應影響之探討
Other Titles:	The Investigation of Free Radicals on Ozonation
Authors:	洪詩涵 Han, Hung Shih
Contributors:	張鎮南 Chang, Cheng-Nan 東海大學環境科學與工程學系
Keywords:	氫氧自由基(?OH);黃酸;臭氧;氧化還原電位;水中溶臭氧;香豆素 (coumarin);高效液相層析儀;涅斯特方程式(Nernst方程式);芬頓 (Fenton) OH radicals;coumarin;HPLC;Ozonation;ORP;DO3;HPLC;Nernst type model;Fenton
Date:	2006
Issue Date:	2011-05-24T08:45:36Z (UTC)
Abstract:	本研究採集之水樣為提供中台灣地區飲用水水源的德基水庫，利用XAD-8樹脂分離出五種有機物質，其中腐植酸佔29.7％、黃酸佔19.5％、疏水性中性物質佔31.2％、疏水性鹼性物質佔2.6％和佔15.7％的親水性物質。天然有機物物質（例如：腐植酸）在經過加氯消毒後，容易形成致癌物或其他消毒副產物有害人體健康，例如：TTHMFP和HAAFP (經過氯氣消毒程序所生成的物質)；結果顯示黃酸形成TTHMFP和HAAFP分別為40.1和67.0 μg/mg DOC，而腐植酸形成TTHMFP和HAAFP為46.2和39.6 μg/mg DOC。德基水庫原水為本研究臭氧反應主要的實驗對象。?OH為臭氧氧化兩個重要路徑中影響極大之中間產物，為探討此兩階段反應之詳細過程，本研究除了建立HPLC分析?OH之技術，並以臭氧氧化反應及Fenton反應系統分別模擬全氧化及間接攻擊之狀況，全部過程皆利用示波儀收集反應過程中之氧化還原電位（ORP）、水中溶臭氧（DO3）、pH的即時數據，並藉由可迅速分析大量資料的分光光譜儀來量測在波長254nm的吸光度，此外，利用高效液相層析儀量化臭氧系統和Fenton系統中分別的?OH 和Coumarin，再利用上述資料來討論臭氧反應機制以及建立臭氧反應中的模擬Nernst方程式。結果得到整個臭氧反應中直接臭氧攻擊佔37.1％而間接?OH反應佔62.9％。最後，利用碳13核磁共振光譜儀和傅立葉轉換紅外線分光光譜儀來探討經過原水臭氧反應後之官能基的改變，但因水樣遭受颱風影響甚大致使官能基變化不明顯。 This study collected natural water samples from Te-Chi Reservoir which provides major domestic water supply in metropolitan central Taiwan area. The water sample organic contents were extracted and classified into humic acids (HAs, 29.7%), fulvic acids (FAs, 19.5%), hydrophobic neutrals (31.2%), hydrophobic bases (2.6%) and hydrophilic fractions (15.7%) by XAD-8 resins. Traditionally, raw water is disinfected by chlorination and some species of natural organic matters (NOMs), e.g. humic acids and their related substances are easily to form carcinogenic or mutagenic by-products. Those substances are often measured via the formation of cancer-causing potentials such as Trihalomethane Formation Potential (THMFP) and Haloacetic Acid Formation Potential (HAAFP) after chlorination. The result shows the FAs have the high THMFP and HAAFP value which was 40.1 and 67.0 μg/mg DOC, respectively. Furthermore, the HAs have the second high values which were 46.2 and 39.6μg/mg DOC individually.The Te-Chi Reservoir raw water was ozonated to investigate the 2-step oxidation reaction mechanisms for this study. The on-line data of oxidation reduction potential (ORP), dissolved ozone (DO3) and pH were collected by an oscilloscope; the absorbance at 254 nm (A254) value was obtained from an on-line UV spectrophotometer (Carry50). The concentration of OH radicals was measured by HPLC (high performance liquid chromatography) in the presence of coumarin. The collected data, ORP, DO3, pH, OH radical and A254, are used to explain the ozone reaction mechanisms and also be used to develop a modified Nernst type model for ozonation. Fenton process was used to simulate the indirect free radical reaction in ozonation, therefore, the indirect hydroxyl radical oxidation contribution can be replaced by Fenton process. The ozone direct reaction and OH redicals indirect reaction contributed 37.1% and 62.9%, respectively.The change of functional groups during ozonation was examined by using 13C NMR (13C nuclear magnetic resonance) and FTIR (Fourier-Transform infrared spectrophotometer) spectra. The functional groups can be found to be destructed by ozonation in this study.
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