以電泳沉積法製備二氧化鈦光觸媒濾網分解甲醛之研究

Research on Decomposition of Formaldehyde by E.P.D. Method Preparing TiO2 Photocatalyst

鄭弘偉(Hung-Wei Cheng)

指導教授 ： 卓清松

國立臺北科技大學/機電學院/能源與冷凍空調工程系碩士班/碩士(2008年)

摘要

電泳沉積法其原理是在一個外加的電壓下，驅動懸浮液中帶有電荷的粒子往與本身電荷相反的電極移動，進而沉積於基板上。本研究以電泳沉積法將二氧化鈦奈米顆粒披覆於不鏽鋼濾網上，並且觀察比較不同懸浮液濃度、pH值、電壓、燒結溫度所製備的二氧化鈦薄膜表面差異。
甲醛氣體是室內最常見的空氣污染物之一，本研究利用一套密閉可變溫濕度的空調循環箱中，安裝以最佳電泳條件所製備的光觸媒濾網來光催化分解降低甲醛有機氣體濃度以達到空氣清淨的功能。探討於室內溫度冬(21℃)夏(26℃)、濕度50%RH、循環風速0.7m/s為空調箱設定條件下，以二氧化鈦濾網片數、紫外光照度為操作參數，對於空調系統中光催化分解污染物甲醛效率之影響。研究結果顯示溫度高時光催化效能愈佳；隨紫外光照度愈大光觸媒光催化效能也愈佳；而隨光觸媒濾網片數增加，污染物與光觸媒表面接觸的面積增加，因此光催化的效能也愈佳。實驗中背景自然吸附的效能最大可達21℃時為13.21%，26℃時為15.93%；而UV光解效能則較不明顯最大可達21℃時為3.57%，26℃為4.48%；光觸媒的光催化效能最大21℃時可達35.59%，26℃時可達36.39%；而整體的甲醛總去除效能21℃時可達51.15%，26℃時可達55.06%。利用本研究所電泳製備的光觸媒濾網可有效降低甲醛有機氣體，達到清淨室內空氣及提升人體健康的效益。

關鍵字

電泳 ； 二氧化鈦 ； 不鏽鋼濾網 ； 甲醛

並列摘要

Regarding the principle of electrophoretic deposition, under an added voltage, the charged particles in the suspension fluid are driven to move towards the electrode being opposite to its electric charge, and further deposited on the base plate. This study employed electrophoretic deposition to let titanium oxide (TiO2) clad on the stainless steel filter, and then observed and compared the difference appeared on the surface of TiO2 thin films prepared by the suspension fluids of different cconcentrations, pH values, voltages and sintering temperatures.
Formaldehyde is one of the commonest air pollutants indoors. The study installed in a set of enclosed air-conditioning chamber with adjustable temperature and humidity with a photocatalytic fiber prepared under the best electrophoretic condition, intending to reduce the concentration of the organic gas of formaldehyde to achieve the function of air purification. Under the conditions that the air-conditioning chamber was preset at an indoor temperature of 21℃ in winter and 26℃ in summer, a humidity of 50%RH, and a circulated wind speed of 0.7m/s, and when the number of TiO2 filters and the ultraviolet illumination were taken as the operation parameters, the study investigated the influence on the photocatalytic decomposition of the pollutant of formaldehyde in the air-conditioning system. The research results show that the higher the temperature, the better the photocatalytic efficiency. As the ultraviolet illumination is greater, the photocatalytic efficiency is better. As the number of photocatalytic filters increases, the contact area between pollutant and photocatalytic surface is enlarged. Therefore, the photocatalytic efficiency becomes better. In the experiment, the greatest efficiency of background natural absorption reaches 13.21% at 21℃, and 15.93% at 26℃. However, the UV photolytic efficiency is comparatively not so obvious, being 3.57% at 21℃, and 4.48% at 26℃. The greatest photocatalytic efficiency can reach 25.59% at 21℃, and 36.39% at 26℃. The overall removal efficiency of formaldehyde can reach 51.15% at 21℃, and 55.06% at 26℃. Using the photocatalytic filters made by electrophoretic preparation by this graduate institute, the organic gas of formaldehyde can be effectively reduced, achieving the effect of clean indoor air and improving the health of human body.

並列關鍵字

Electrophoretic ； TiO2 ； Stainless steel filters ； Formaldehyde

參考文獻

[1] Klepeis N.E., Nelson W.C., Ott W.R., Robinson J.P., Tsang A.M., Switzer P., Behar J.V., Hern S.C. and Engelmann W.H., “The National Human Activity Pattern Survey (NHAPS): a resource for assessing exposure to environmental pollutants,” Journal of Exposure Analysis and Environmental Epidemiology, vol. 11, no. 3, 2001, pp. 231-252.

[2] A. Fujishima and K. Honda, “Electrochemical photolysis of water at a semiconductor electrode,” Nature, vol. 238, 1972, pp. 37-38.

[6] P. Sarkar and P. S. Nicholson, “Electrophoretic deposition (EPD): mechanisms, kinetics, and application to ceramics,” J. Am. Ceram. Soc., vol. 79, 1996, pp. 1987-2002.

[7] K. Kamada, K Maehara, M. Mukai, S. Ida and Y. Matsumoto, “Fabrication of metal oxide-diamond composite films by electrophoretic deposition and anodic dissolution,” J. Mater. Res., vo1. 8, 2003, pp. 2826-2831.

[8] A. T. Kuhn (ed.), Industrial Electrochemical Processes; Amsterdam, The Netherlands, Elsevier, 1971, pp. 128.