鹵化銀覆鍍氮改質二氧化鈦觸媒特性分析及其光催化環丙沙星之研究

Characterization of Nitrogen-doped Titanium Dioxide Modified with Silver Halide and Its Performance on Ciprofloxacin Removal by Photocatalyzation

陳貞汝(Chen Zhen-Ru)

指導教授 ： 陳冠中

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2021年)

https://doi.org/10.6346/NPUST202100468

摘要

近年來，抗生素為新興污染物之一，人類在畜牧養殖與醫療行為上 大量使用抗生素的情形下，造成抗生素例如環丙沙星(Ciprofloxacin, CIP) 存在於生活污水與醫療廢水中。因此，有效去除廢水中的抗生素為現今 的重要課題。本研究以 N-TiO2 為基底，經由沉積沉澱法摻雜鹵化銀(AgI、 AgBr 與 AgCl)製備三種光觸媒(AINT, ABNT,以及 ACNT)，再利用光纖提 供光源，進行光催化去除 CIP 之研究。研究以 SEM/EDS、XRD、DRS 進行光觸媒特性分析，由 SEM/EDS 分析結果發現，改質光觸媒皆顯示鹵 素成功摻雜於光觸媒中;由 XRD 結果分析得知，摻雜 AgI 之光觸媒(AINT) 因為添加劑量過低，導致 XRD 沒有分析到 AgI 晶相，另外，摻雜 AgBr (ABNT)和 AgCl (ACNT)之光觸媒，XRD 強度隨著添加劑量增加而提高; DRS 之分析顯示 AINT、ABNT 與 ACNT 之光觸媒吸收波段延伸至可見 光區域，其能隙與氮改質二氧化鈦(2.95 eV)相比皆有降低，其範圍依序分 別為 2.5-2.57 eV、2.3-2.8 eV 與 2.75-2.85 eV。
本研究探討之操作參數包括光觸媒種類、光觸媒劑量、CIP 初始濃度與 LED 之光源波長。先藉由批次實驗在不同光觸媒摻雜劑量(5%, 10%與20%)下，其他條件固定不變進行實驗，結果發現 5%之改質光觸媒處理CIP 效果最佳，故作為後續實驗之固定條件。而在光纖光催化實驗中，以光纖之端點進行光催化 CIP，探討不同實驗條件下之光催化效率，結果得知三種光觸媒中，以 5% ACNT 在紫外光之 CIP 去除效果最佳，去除率可達 88.1%，再由不同 CIP 初始濃度與光觸媒劑量之實驗結果發現，初始濃度 1 mg/L 之光催化去除效果會高於 3 mg/L，而光觸媒添加劑量以 10 mg較5 mg佳。因此，後續覆鍍光觸媒於光纖表面之實驗，以CIP初始 濃度 1 mg/L 與 10 mg 光觸媒劑量作為固定條件，進行光纖側光光催化實 驗，紫外光及可見光光催化 CIP 之去除率分別為 44.6%和 21.4%。研究結 果顯示改質後之光觸媒，均可以在紫外光和可見光波長進行 CIP 光催化 處理，但是在紫外光照射下之光催化效果較佳。

關鍵字

光催化 ； 光纖 ； 環丙沙星 ； 鹵化銀

並列摘要

In recent years, antibiotics are emerging pollutants extensively used in animal husbandry and medical behavior. This results in detectable levels of antibiotics, such as ciprofloxacin (CIP) exist in domestic sewage and medical wastewater. Therefore, the effective removal of antibiotics from wastewater is an important topic today. This study prepared three photocatalysts by doping silver halide (AgI, AgBr and AgCl) with N-TiO2 as the substrate. An optical fiber was used to irradiate these photocatalysts for CIP photocatalysis. The characteristics of photocatalyst were analyzed by SEM/EDS, XRD, and DRS. The results of SEM/EDS analysis show that halogen elements were successfully doped in the photocatalysts. Regarding the peak intensity analyzed by XRD, the addition of AgI to N-TiO2 (AINT) was not detected due to its low amount. The XRD intensity of ABNT (AgBr doped in N-TiO2) or ACNT (AgCl doped in N-TiO2) was detectable and increased with the increase of the doping percentage. The DRS analysis shows that the absorption band of AINT, ABNT and ACNT extended to the visible region, and the energy gap reduced to 2.5-2.57 eV, 2.3-2.8 eV and 2.75-2.85 eV, respectively, compared to N-TiO2 of 2.95 eV.
The investigation of operating parameters includes type of photocatalysts, photocatalyst dose, initial concentration of CIP and wavelength of LED. Batch experiments were carried out at different doping percentages (5%, 10% and 20%) with other parameters fixed. The results show that 5% doping photocatalyst performed the best removal efficiency on CIP photocatalyzation. Therefore, photocatalysts with 5% doping were used for all the following experiments. Then the photocatalysis of CIP was conducted by using the endpoint of an optical fiber to illuminate photocatalyst powder in a reactor. The experimental results show that among the three photocatalysts, ACNT had the best efficiency when illuminated by ultraviolet (UV) LED, and its removal rate reached 88.1%. It was also found that the lower initial concentration of CIP (1 vs. 3 mg/L) and the higher photocatalyst dosage (10 vs. 5 mg) decreased more CIP during photocatalysis. Therefore, 1 mg/L of CIP was used as the initial concentration, and 10 mg of the photocatalyst was coated on the surface of an optical fiber in the subsequent experiments. The photocatalysis of CIP by an optical fiber coated with photocatalysts irradiated by different light sources was investigated. It shows that the removal rates of UV and visible LEDs were 44.6% and 21.4%, respectively. According to the results of this study, the modified photocatalysts could be used for CIP photocatalysis under both UV and visible LEDs irradiation. Still, the former showed better performance than the latter.

並列關鍵字

Photocatalysis ； optical fiber ； ciprofloxacin ； silver halide

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