進階型超音波程序降解四環素類抗生素廢水之研究

Degradation of Tetracyclines Antibiotic Wastewater by Processes of Assisted Sonolysis

本研究利用連續加藥之進階型超音波程序（Assisted Sonolysis）對四環素之降解、礦化以及毒性變化進行探討，並調整反應程序中之金屬離子（Fe2+、Ag+、Co2+）與搭配之氧化劑（H2O2、S2O82-），確認最合宜之處理程序，再經由不同實驗參數之影響，評估此一程序對於四環素廢水處理之可行性。實驗結果發現，使用單獨超音波程序反應60分鐘後，初始濃度50 mg/L之四環素降解與礦化率僅有6.7%及3.2%，添加Fe2+、Co2+與Ag+與超音波結合後，四環素降解率微幅提升，但最高僅為9.8%；將超音波和三種金屬離子及兩種氧化劑組合的六種程序實驗結果顯示，Fe2+ 之添加對於實驗進行具有較佳之效率，四環素之去除率最高可達到93%。反應中提高Fe2+及H2O2之加入量均有助於提高四環素之降解與礦化，但當Fe2+及H2O2之加入量分別在0.2 mM及2 mM以上時，四環素之降解與礦化反而略有降低，顯示過量的試劑添加不利於氧化反應之進行。在初始pH 3 - 6進行實驗時則發現，pH值的差異對四環素降解效率影響並不顯著；隨著礦化率的提高，細胞存活率也隨之提升，顯示在合宜的操作條件下，四環素的毒性顯著降低，同時，四環素的礦化為毒性降低之關鍵機制。

This study investigated the degradation, mineralization and detoxicity of tetracyclines by a continuous dosing assisted sonolysis and discussed the effect of reaction parameters such as the types of transition metals and oxidants to find out the better operational design. Based on the results observed in this study, the feasibility of continuous dosing assisted sonolysis on tetracycline degradation were also investigated. Experimental results indicated that the degradation and mineralization of tetracycline with the initial concentration of 50 mg/L were 6.7% and 3.2%, respectively, by a sole ultrasound with 60 mins reaction. As the transition metals were added into the solution, degradation of tetracycline slightly increased to as high as 9.8% where the Fe2+ showed the better performance. Coupling the ultrasound, transition metals and oxidants indicated that the combination of ultrasound/Fe2+/H2O2 was effective on the degradation of tetracycline where the maximum result was 93%. Increasing of Fe2+ and H2O2 were useful to enhance the degradation and mineralization of tetracycline. As the concentration of Fe2+ and H2O2 were greater than 0.2 mM and 2 mM, the results of tetracycline degradation and mineralization decreased which indicated that the exceed amounts of Fe2+ and H2O2 were worthless to the process. The effect of pH on the experiments was insignificant as the pH values were between 3-6. There was a satisfactory relationship between the tetracycline mineralization and increase of cell viability, which indicated that the mineralization of tetracycline was the key step to decrease the toxicity of water samples.