- 學位論文
以氧化石墨烯催化之臭氧處理程序降解酮洛芬、布洛芬及草脫淨
Degradation of ketoprofen, ibuprofen and atrazine by catalytic ozonation with graphene oxides
摘要
微污染物(Micropollutants, MPs)在水和廢水中被發現一直受到生態和人類健康方面的關注也是關於水回收的新興問題。臭氧程序已被應用於降解微污染物，但對於臭氧難降解污染物的去除有限。為了進一步改善臭氧難降解污染物的去除，利用催化臭氧化來增強氫氧自由基(Hydroxyl radical, OH•)的形成可以更有效降解這些污染物。本研究的目的是利用氧化石墨烯(Graphene oxides, GOs)催化臭氧程序去除臭氧難降解微污染物，包括酮洛芬、布洛芬和草脫淨。使用不同濃度的過錳酸鉀預處理氧化石墨烯合成具有不同表面氧化程度的氧化石墨烯。氧化石墨烯在臭氧和氫氧自由基鏈反應中的直接反應(Direct reaction)、起始反應(Initiation)、促進反應(Promotion)和抑制反應(Inhibition)的速率常數在不同的pH和氧化程度下皆被測定。結果顯示 GO-3(過錳酸鉀:石墨=3:1)具有最高的起始和抑制能力，羥基(Hydroxyl groups, C-OH)是產生氫氧自由基的活性位點。此外，直接反應、起始反應和抑制反應的速率常數隨著pH值的增加而增加，而促進反應的速率常數沒有明顯的趨勢。速率常數隨氧化石墨烯氧化程度與pH值的變化可歸因於氧化石墨烯表面上大量的含氧官能團(包括羥基、羰基、羧基和環氧基)。由於氫氧自由基的增加，使用氧化石墨烯催化臭氧化可以增加酮洛芬、布洛芬和草脫淨的去除率。結合氧化石墨烯的四個速率常數，可建立模型模擬污染物在催化臭氧程序中的去處情況，並顯示良好的去除效率預測。
並列摘要
The presence of micropollutants (MPs) in water and wastewater has been a concern for ecological and human health. This is also an emerging issue in water reclamation. Ozonation has been applied for MPs abatement but limited removal of ozone-recalcitrant compounds was reported. To further improve the removal of ozone-recalcitrant compounds, catalytic ozonation has been employed to enhance hydroxyl radical (OH•) formation for better degradation of these compounds. The aim of this study is to investigate the removal of ozone-recalcitrant MPs including ketoprofen, ibuprofen and atrazine by catalytic ozonation with graphene oxides (GOs). Different concentrations of KMnO4 were used to pre-treat GOs to achieve different degrees of oxidation on the GO surfaces. The rate constants of GOs in terms of direct ozone reaction (kD), initiation (kI), promotion (kP) and inhibition (kS) in the ozone and hydroxyl radical (OH•) chain reactions were quantified at different pH values and oxidation degrees. It was found that GO-3 (KMnO4: graphite = 3:1) possessed the highest initiation and inhibition capacity and C-OH could be an active site for generating OH•. In addition, the rate constants of direct ozone reaction, initiation and inhibition increased with the increasing pH value, while the rate constants of promotion presented no obvious trend. The variations of the rate constants with pH and oxidation degree of GOs could be ascribed to the abundances of oxygen-containing functional groups including hydroxyl, carbonyl, carboxyl and epoxy groups on the GOs surfaces. The removal of ketoprofen, ibuprofen and atrazine was enhanced by catalytic ozonation with GOs due to improved OH• formation. The removal of these three compounds can be well predicted by incorporating the rate constants of GOs into the degradation kinetic model.