| 摘要: | 水是人類不可或缺的資產，然而如果被有害的化學物質污染，水資源將無法妥善利用，其中工廠排放的廢水通常含有複雜且有害的有機化合物，可以藉由污水處理程序以獲得乾淨的水源。關於污水處理，已經有諸多研究證實可以降解廢水中的有機污染物。例如，鈣鈦礦材料由於其優異的光催化活性，在污水處理的應用上，呈現優異的結果。如果將鈣鈦礦材料結合適當的集電體基材，則可以誘導其電催化效果。在本研究中，我們嘗試利用具有三維網絡結構且導電的碳纖維作為集電體基材與鈣鈦礦材料結合，製備鈣鈦礦/碳纖維複合電極，應用於有機污水處理。
本實驗透過修飾溶膠凝膠程序製備鈣鈦礦/碳纖維電極。首先將數種硝酸鹽和檸檬酸藉由溶膠凝膠法獲得YFeO3先驅物，再將YFeO3先驅物以不同目標溫度進行鍛燒，形成粉末狀YFeO3。最後將YFeO3粉末塗佈於碳纖維上，製備出複合電極。
用X射線繞射分析儀(XRD)，熱重分析儀(TGA)和掃描式電子顯微鏡(SEM)分析了複合材料的性能。此外透過由複合電極組成的光電催化系統來進行有機污水處理。根據特性分析實驗結果顯示，碳纖維經由前處理程序可將表面環氧樹脂除去以提高導電性；YFeO3具有良好結晶性且傾向形成團聚的多孔性結構；複合電極則證實YFeO3成功地塗佈在碳纖維上。汙水處理應用實驗結果顯示，YFeO3光催化在可見光下經過120分鐘後的去除效率為51%；複合電極光電催化的最佳條件為0.75 mM FeSO4、25℃、pH 3.0、可見光光源，去除效率經過30分鐘後達到96%，擬二級反應動力常數為0.0387 L mg-1 min-1。藉由電化學阻抗譜分析得知，較低的電荷轉移阻抗可以有效提升有機污水的去除效率。
;Water is an indispensable asset for human; however, it immediately becomes unavailable if contaminated by harmful chemical substances. Particularly, industrial wastewater composed of complicated chemical compounds usually accounts for the serious issue. With regard to wastewater treatment, many methods have been proved to be able to degrade organic pollutants. For example, perovskite materials can be applied on organic wastewater treatment due to their photocatalytic reactivity. If perovskite materials are further integrated with a proper electrical conductor, their electrocatalytic effect can be induced. In this study, we try to utilize carbon fibers (CFs), which possesses three-dimensional electrically conductive network, as current collectors to combine with perovskite materials, making a perovskite/CF electrode for organic wastewater treatment.
For the experiment, we prepared the perovskite/CF electrode through a modified sol-gel process. First, YFeO3 precursors were made by several kinds of nitrate and citric acid with sol-gel method. Then, YFeO3 precursors experienced a calcination process with different temperatures as a parameter, forming a powder-type product. Finally, we coated the YFeO3 powders on carbon fibers to make the composite electrode.
X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) were used to analyze the composite material properties. In addition, a photo-electrocatalytic system composed of the perovskite/CF electrode was established to carry out the organic wastewater treatment. Based on the analyzed results, YFeO3 possessed a good crystallinity and they tended to form aggregates with porous structure; it is also confirmed that YFeO3 successfully deposit on the carbon fibers, forming the composite electrode. As for the wastewater treatment, the removal efficiency can achieve 51% through a 120-min YFeO3 photocatalysis; the YFeO3/CF composite electrode exhibits a favorable photo-electrocatalytic activity of 96% at 0.75 mM FeSO4, 25℃ and pH 3.0 under visible light irradiation after a 30-min treatment, and rate constant k is calculated as 0.0387 Lmg-1min-1. According to electrochemical impedance spectroscopy (EIS), the composite electrode effectively degrade organic pollutants due to smaller charge transfer resistance. |
