熱鍛燒法製備二氧化鈦披覆鈦基光陽極於電化學輔助光催化降解orange G染料之研究

Abstract

染整工業的興起帶動染料的發展，傳統染整工業廢水具有高濃度有機污染物及高色度等特性，若未經處理而排放易導致環境污染。近年來高級氧化處理程序(AOP)已逐漸被應用於染整廢水之降解脫色，其中二氧化鈦光催化程序最廣泛被研究及應用。因此，本研究利用直接鍛燒法(direct calcination)在不同溫度下於鈦網基材上氧化生成覆膜型二氧化鈦光陽極，並應用於光電催化(photoelectro-catalysis)系統以評估其對染整廢水處理之可行性。同時，使用ICP-MS、XRD、SEM及XPS分別觀察二氧化鈦晶相、氧化態、金屬組成與型貌之分析。此外利用電化學法中電流平衡(current balance)原則定義不同鍛燒溫度下之最佳電性參數。最後將此材料作為光陽級應用於偶氮型染料廢水orange G之降解試驗，嚐試使用不同AOP法進行，如：光催化、電催化、光電催化與光電芬頓法(photoelectro-Fenton)，探討系統中之降解機制與效能上之差異。 研究結果顯示，鈦網酸洗過後在空氣以700oC鍛燒2小時，可生成具有最佳分散性且晶粒尺寸大、表面積大金紅石相二氧化鈦，其具有最大光電流密度大小226.57μA cm-2。同時利用電化學制定電性參數，令電極面積在電流平衡條件下有最大利用率，而針對光遮蔽性染料OG脫色率依序為：光電芬頓法>光電催化>電催化>光催化，結果顯示在反應時間3小時過後，光電芬頓催化法可達最大脫色率38.48%，有效完成高效淨水之目的。

The rise of dye industry leads to large quantity of dye wastewater. Dye wastewater are rich in high organic content, which has chroma characteristics. The dye waste water will pollute water body and damage the aquatic ecological system if they are not treated properly prior being discharged. Advanced oxidation processes (AOP) are started to receive more attentions in treating dye wastewater decolorization.Recently, photo-catalysis process by using titanium dioxide (TiO2) was the most widely applied technique for this process . In this thesis, We focus on the fabrication of TiO2 films on Ti mesh substrate by direct calcinations process by applying different calcination temperatures. The photoelectron – chemical properties of the as prepared titanium dioxide-coated titanium photoanodes were also investigated. The surface morphology, crystal phase, and chemical composition were investigated using ICP-MS, XRD, SEM and XPS, respectively. In addition, optimum electrical parameters was determined by using electrochemical current balance. Furthermore, the fabricated titanium dioxide-coated titanium photoanodes were applied for degrading azo d acid orange G.The dye degradation efficiency of TiO2 photoanode films were applied in different combined-energy system, including： photolysis, photo-catalysis electro-catalysis, photoelectro- catalysis and photoelectro-Fenton catalysis were evaluated. The well-fabricated rutile titanium dioxide-coated titanium photoanodes in this study shows a high photocurrent density of 226.57μA cm-2 with great dispersion, big surface area and large crystalline size.The samples were prepared by applying HCl for surface cleaning, post treatment calcined at 700oC in air for 2 hours subsequently. The maximum utilization of electrode area were under the electrochemical current balance. The order of degradation modes with respect to decreasing the degradation efficiency of OG is： PEF > EPC > EC > PC oxidation. In the feasibility test for dye degradation, photoelectro-Fenton catalysis system using TiO2 photoanode achieved high decolorization rate 38.48% for 3 hours. Therefore, these results suggest that titanium dioxide-coated titanium photoanodes prepared in this study is suitable for the application of dye wastewater treatment to achieve high removal efficiency in order to accomplish effective water purification purpose.