氧化法製備二氧化鈦膜及光催化染料之研究

本研究分為微弧氧化、鹼處理、熱處理三個製備階段參數進行氧化膜製備，分別研究三個階段不同參數對亞甲基藍光催化效果差異。批次實驗利用波長365 nm黑燈管進行染料溶液批次光催化，進行染料溶液循環流動光催化實驗利用UV-LED燈，對染料溶液去除率進行分析比較。第一階段為微弧氧化製備參數，在陽極鈦金屬施加電壓，鈦金屬表面發生電崩潰、融化、氣化、化學反應、擴散、凝固和相變化等物理化學過程，鈦金屬表面形成二氧化鈦膜；第二階段製備參數為鹼處理將氧化膜改質；第三階段製備參數為高溫煅燒。染料溶液的批次實驗研究結果顯示，體積20 mL、濃度10 mg/L的亞甲基藍染料溶液，以2.5×5 cm2二氧化鈦膜，在2.64 mW/cm2光輻射強度下照光1小時。二氧化鈦膜未經鹼處理僅將染料降解20.5%；二氧化鈦膜經24小時浸漬40°C的1.25 M之NaOH鹼處理後，可將染料降解34.3%；經3小時400°C熱處理後可將染料降解34.8%，可證實經鹼處理之二氧化鈦膜對染料降解率有大幅度提升。染料溶液的循環流動實驗則為一連續循環之流動染料溶液系統，包括蠕動泵浦、UV/Vis流動偵測槽及連接管路，流速1.6 mL/min，照射面積為8.04 cm2圓形區域，體積6 mL、濃度為10 mg/L的亞甲基藍染料溶液，以波長365 nm且光輻射強度20 mW/cm2的UV-LED照光2小時，每隔15分鐘檢測一次亞甲基藍濃度降解率。最大降解率為經1.25 M之鹼處理二氧化鈦膜，0.5 V外加偏壓光催化，可降解37.3%亞甲基藍濃度，表示光電催化對於降解染料有提升效果，0 V外加偏壓光催化與單純光催化反應相比，降解濃度提升了2.9%。二氧化鈦膜之XRD分析結果可看出光催化效果較佳之二氧化鈦膜的銳鈦礦相（101）之衍射（繞射）強度較高；光催化效果較差之二氧化鈦膜金紅石相及鈦的衍射強度較高。二氧化鈦膜之SEM分析結果可看出較佳光催化效果的二氧化鈦膜，膜表面孔洞較密集且氧化膜偏向叢雲狀。

關鍵字

微弧氧化；鹼處理；熱處理

並列摘要

The experiment is divided into three stages for study the in photocatalytic effects with different oxide films. Batch experiment uses Wood's lamp of 365 nm. Use UV-LED to compare the photocatalytic and the photo-electrocatalytic effects on the dye solution removal rate used for the recycling experiment. First, Micro-arc Oxidation must run with a high potential which breakdown the surface layer of oxide in anodes. Dielectric breakdown in the process causes, melting, gasification, chemical reactions, diffusion, solidification and phase transformation and leaves an oxide layer on metal surface. Second, alkali oxide film modification can changes phase in titanium metal surface. Third, high temperature calcination, the best photocatalytic properties of the oxide film. Batch experiment results show with light intensity of 2.64 mW/cm2, volume of 20 mL with 10 mg/L of methylene blue, TiO2 film area 2.5×5 cm2 for 1 hour, only 20.5% degradation is observed without alkali treatment. For 24 hr immersion in 40°C of 1.25 M lye, the dye is degraded 34.3%; After 3 hr and 400°C heat treatment the dye degradation was 34.8%. The cycling experiment is performed at light intensity of more than 20 mW/cm2 and continuous circulation consists of peristaltic pump, UV/Vis flow detection cell and connecting line with flow rate of 1.6 mL/min. Irradiation is on a circular area 8.04 cm2. Firsting out of prepared 10 mg/L methylene blue, take the volume of 6 mL and pour into the beaker UV/Vis absorbance with continuous circulation device detection groove equiped. During 2 hr of UV-LED illumination samples are target every 15 minutes for degradation efficiency different. The maximum degradation efficiency for a biasing voltage of 0.5 V, with a 1.25 M alkaline treatment on the titanium plate is 37.3%, indicating the photo-electrocatalytic degradation of dyes is enhanced. XRD detection for the angle of 20°~75° to detect the diffraction intensity for each of increment of 0.02°. The results can be seen as long as the photocatalytic effect of the titanium plate A（101） anatase phase diffraction intensity is higher. Rutile phase with poor catalytic performance and higher diffraction intensity of titanium. SEM detection of the sample plane and the side to shoot at 2500 times magnification, it can be seen that the oxide film with better photocatalytic effect has more dense pores and thicker oxide film tending to cluster clouds.