二氧化鈦塗佈之不？鋼網對亞甲基藍水溶液光催化效能的探討

Study on the Treatment of Methylene Blue in Aqueous Solution via TiO2 Photocatalyst dip-coated Stainless Steel Plate

本研究利用二氧化鈦塗佈之不銹鋼網進行光催化反應降解亞甲基藍水溶液。鋼網製作是使用奈米級二氧化鈦粉末加入乙基纖維素結合形成鍍膜液，將完成的鍍膜液浸鍍在鋼網片，放置於光催化反應器以分解溶液中的染料。利用上述鋼網在光源照射下，進行對亞甲基藍水溶液光催化反應，探討不同光源、鋼網片數、擺放方式及反應物濃度等反應條件，評估鋼網型觸媒對亞甲基藍之光催化效能。本研究使用的二氧化鈦粉末與鍍膜液經由XRD鑑定為銳鈦礦，經公式換算觸媒粒徑約30nm~50nm，粉末之比表面積BET為790平方公尺／g。二氧化鈦不銹鋼網於亞甲基藍水溶液5ppm、鋼網片數2片與光線垂直方式擺放，在365nm紫外光和480nm可見光照射下，六小時脫色率分別為98.58%和27.47%，顯示自製鋼網屬於紫外光型光觸媒鋼網。脫色率和鋼網片數有關，鋼網片數超過2片（含）以上時，其光催化效能優於單片者；光催化效能與鋼網擺放方式或光源入射的角度有關，與光源垂直擺放的脫色率優於與光源平行擺放者；由反應速率常數得知，反應物之脫色率隨著反應物初始濃度的提升而遞減：在耐用性方面，亞甲基藍5ppm在重覆使用四次後，其六個小時脫色率皆維持95%，顯示自製光觸媒鋼網之耐用性頗佳，若將反應物濃度提昇至100ppm，其脫色率隨著使用次數之增加而遞減。

In this paper, Stainless steel plates were developed with coated TiO2 catalyst for the photocatalytic oxidation of methylene blue (MB). The stainless steel plate was dip-coated by TiO2 nano-catalyst mixed with ethyl cellulose and to decompose dyes by a photocatalytic reactor. Via rate of color removal, performance of TiO2 catalyst dip-coated stainless steel plate was evaluated by reaction conditions like the light source, number and the lay of dip-coated stainless steel plate, and initial concentration of MB. The characterization of catalysts of XRD showed both TiO2 powder and Ti02 powder mixed with ethyl cellulose are anatase crystalline phase. The diameter of catalysts was around 30 to 50nm, which the BET was 7.90m^2/g. The TiO2 catalyst dip-coated stainless steel with 2 plates, a vertical plane to the light source of 365nm and 480nm, enables 98.58% and 27.47% color removal respectively after 6h of reaction in the 5ppm MB solution, showed the TiO2 plates were valid for the UV irradiation. The efficacy of photocatalytic oxidation was relative to the number of dip-coated plate, which 2 and above plates was superior to one plate, and also vertical plane to the light source was more efficient than parallel plane. The reaction rate constant showed the color removal decreased as initial MB concentration was raised. As for efficiency of catalyst durability, it was found that TiO2 dip-coated stainless steel plate performed 95% color removal at 5ppm MB even after 4 times repeated usage, which showed favorable durability. However, when the concentration up to 10 ppm, the color removal decreased as the used counts was raised.