以二氧化錳去除水中乙醯胺酚之研究

Removal of Acetaminophen in water by Manganese Dioxide

李怡儒(I-Ju Lee)

指導教授 ： 胡景堯

臺北醫學大學/公共衛生暨營養學院/公共衛生學系暨研究所/碩士(2013年)

摘要

自然環境中，乙醯胺酚(Acetaminophen)為一常見的消炎止痛藥物，其降解產物可能會對於生物及人體造成危害。氧化/氫氧化錳為天然礦物中重要的氧化劑之ㄧ，其相當好的氧化還原能力，可有效的降解有機物質，針對於酚(Phenol)、氯酚(Chlorophenol)及苯胺(Anilines)類化合物有良好的分解效果。本研究是以批次實驗對於乙醯胺酚在二氧化錳(β-MnO2)之反應進行探討，並討論其反應動力學、影響因子、去除機制及反應途徑，並加入輔助吸附劑對於乙醯胺酚的去除是否會造成影響。
實驗結果發現乙醯胺酚可有效被二氧化錳降解，而二氧化錳的劑量增加且反應溫度的提高，則會加速反應速率；二氧化錳去除乙醯胺酚之機制，在酸性條件下，以吸附及氧化作為主要的去除機制，而中性及鹼性則以氧化作用為主，其原因可能是因為於鹼性溶液中，會發生水解反應而使乙醯胺酚發生降解；此外以化學分析影像能譜儀(ESCA)鑑定二氧化錳表面錳價數之改變，發現隨酸鹼值的增加，Mn(Ⅱ)所佔之表面比例也隨之增加，證明高酸鹼值的環境，以氧化作用為主要機制；反應動力學的研究則發現在短時間內乙醯胺酚的降解反應可符合擬一階反應動力式；在鹼性的環境下，加入輔助吸附劑(陽離子型的界面活性劑CTAB)會增加二氧化錳對於乙醯胺酚的吸附量，進而增加其去除效果。副產物定性部分，利用HPLC-DAD及LC-MS鑑定所生成產物，發現乙醯胺酚降解後會產生毒性較高的對苯二醌(p-Benzoquinone)及一些聚合體產物，此研究有助於進一步瞭解環境中乙醯胺酚之宿命。

關鍵字

乙醯胺酚 ； 二氧化錳 ； 化學分析影像能譜儀 ； 陽離子型的界面活性劑 ； HPLC-DAD ； LC-MS ； 對苯二醌

並列摘要

Acetaminophen has been widely found in the environment. It and its degradation products may be toxic for human and aquatic species. Manganese oxides/hydroxides are among the most important naturally occurring oxidants in facilitating organic pollutant transformation in soils and sediments and deserve particular attention due to their high reduction potentials. It is effective oxidants for a wide range of pollutants including phenols, chlorophenol and anilines. In this study, batch experiment will be used to investigate the reactivity of acetaminophen with manganese dioxides. The kinetics, influencing factors, removing mechanism and pathways of acetaminophen removed by β-MnO2.The effects of addition of adsorption assistants (surfactants) on the reaction will also be investigated.
The results indicate that acetaminophen can be effectively degraded by β-MnO2. The reaction rate increased with the increase of the initial β-MnO2 loading and temperature. When the solution is acid, the main removal mechanisms were adsorption and oxidation. Oxidation, however, is the only main removal way to transform acetaminophen in neutral and alkaline solution. This result may be due to the higher hydrolysis (which is the first step for acetaminophen degradation) rate of acetaminophen in alkaline solution. The results of Electron Spectroscopy for Chemical Analysis (ESCA) revealed that as pH increasing, the Mn(Ⅱ) proportion increase in the β-MnO2 particle surface. The kinetics of this reaction can be fitted by pseudo-first-order model. In the presence of CTAB, a cationic surfactant, can enhance the adsorption of acetaminophen in high pH solution. HPLC-DAD and LC–MS was used to identify oxidation products, which include p-benzoquinone and some dimers. These results are useful in understanding the fate of acetaminophen in natural systems.

並列關鍵字

Acetaminophen ； β-MnO2 ； ESCA ； CTAB ； HPLC-DAD ； LC–MS ； p-benzoquinone

參考文獻

1. Fatta, D., A. Achilleos, A. Nikolaou, and S. Meric, Analytical methods for tracing pharmaceutical residues in water and wastewater. TrAC Trends in Analytical Chemistry, 2007. 26(6): p. 515-533.

2. Fang, T.H., F.H. Nan, T.S. Chin, and H.M. Feng, The occurrence and distribution of pharmaceutical compounds in the effluents of a major sewage treatment plant in Northern Taiwan and the receiving coastal waters. Mar Pollut Bull, 2012. 64(7): p. 1435-44.

3. Kim, S.D., J. Cho, I.S. Kim, B.J. Vanderford, and S.A. Snyder, Occurrence and removal of pharmaceuticals and endocrine disruptors in South Korean surface, drinking, and waste waters. Water Research, 2007. 41(5): p. 1013-1021.

4. Fram, M.S. and K. Belitz, Occurrence and concentrations of pharmaceutical compounds in groundwater used for public drinking-water supply in California. Science of the Total Environment, 2011. 409(18): p. 3409-3417.

5. Bound, J.P. and N. Voulvoulis, Pharmaceuticals in the aquatic environment--a comparison of risk assessment strategies. Chemosphere, 2004. 56(11): p. 1143-55.