聚光追日搭配氧化劑處理系統之建置及應用於處理污水中藥物污染之可行性研究

Abstract

藥物及個人保健用品（pharmaceuticals and personal care products, PPCPs）為近十年於環境水體中頻繁被檢出的一類新興污染物，其濃度分佈為ng/L-μg/L。由於部分藥物無法經由一般生物處理程序完全去除，但卻被認為可藉由光降解程序有效地降解，目前已應用於污水處理程序之光解程序多以UV光配合其他氧化方法去除廢水中的藥物。然而，UV光照設備需耗費較多能源及操作經費，為節省光降解藥物處理系統的耗能情形，本研究目標為設計一套聚光處理系統，利用太陽光降解環境水體中的藥物，並以實驗室之模擬光照研究探討最適化之處理條件；此外，為提升聚光的效果，將聚光系統配合追日系統，並提高聚光系統反射面的UV光反射率，使太陽光聚集的能量最大化。 研究中以廣泛被人類及動物使用且常在環境水體中存在的兩種抗生素－ciprofloxacin及sulfamethoxazole做為目標污染物，測試聚光追日系統以及於系統內添加氧化劑對於提升其光降解效率的效果。研究結果顯示相較於直接照射太陽光之系統，在台灣夏季正午，改良後之聚光追日系統對水中ciprofloxacin降解效率可增加約40%-48%，而對sulfamethoxazole之降解率可增加約4.2%-13.6%。為加強系統處理效果，在聚光追日系統中添加氧化劑，將1 mg/L 次氯酸根（HOCl, OCl−, free chlorine, FC）加入系統中，相較於直接照射太陽光的系統，sulfamethoxazole降解效率最高可增加達33%；而添加50 mg/L 過硫酸根（S2O82- , persulfate, PS）在系統中，sulfamethoxazole降解效率最高可提升達61%。由於PS不僅可藉由光激發，也可被熱激發，改良後之聚光追日系統除了可增加光強度外，亦可增加系統溫度，結果顯示在系統中添加PS對sulfamethoxazole的光降解確有明顯加成效果。本研究在聚光追日系統添加50 mg/L PS對於降解水中sulfamethoxazole獲得最佳降解效率，故藉由聚集的光及熱激發PS生成硫酸自由基（·SO4−）於此系統中極具應用之優勢。綜合以上結果，聚光追日系統配合氧化劑添加做為降解水中藥物污染的水處理程序實具有發展的潛力。

Pharmaceuticals and personal care products (PPCPs) are commonly detected in the aqueous environment at ng/L to ng/g concentration levels since pharmaceuticals in wastewaters cannot be effectively removed through biological wastewater treatment. In recent years, UV based advanced oxidation procedures (UV-AOPs) was applied to improve degradation of PPCPs; however, energy consumption and power costs are important issues. Therefore, this study is aimed to design a sunlight concentrator treatment system to replace UV lamps for further degradation of pharmaceuticals. To increase efficiency of the sunlight concentrator treatment system, the sunlight tracker was used jointly in this study, and the surface of concentrator was also modified to enhance UV reflection rates. Two common antibiotics, ciprofloxacin and sulfamethoxazole, were chosen as target compounds in this study. The results show that degradation efficiencies of ciprofloxacin and sulfamethoxazole respectively increased in water-based substrate as high as 40%-48% and 4.2%-13.6% in the enhanced system at noon on the summer of Taiwan compared with direct sunlight photolysis system. In order to further improve the degradation efficiency of the system, free chlorine (HOCl, OCl−, FC) and persulfate (S2O82- , PS) were added. For sulfamethoxazole, 1 mg/L of FC addition could lead to 33% increase of degradation efficiency, and 50 mg/L of PS addition could improve further degradation as high as 61%. The enhanced system can not only collect sunlight but also raise the temperature in the reactor. Because PS can be activated by light and heat, the enhanced system was suitable to activate PS to generate sulfate radical (·SO4−) and degrade sulfamethoxazole. The result shows that PS addition leads to synergic effect on sulfamethoxazole degradation in the system. Therefore, this developed sunlight concentrator treatment system will have potential to be utilized in the wastewater treatment process.