UV Oxidation-Process Development for Degradation of Organic Trace Compounds in Water

Research Project

Project/Area Number	59850154
Research Category	Grant-in-Aid for Developmental Scientific Research
Allocation Type	Single-year Grants
Research Field	反応工学
Research Institution	Akita University
Principal Investigator	SUGAWARA Takuo Professor, Mining College, Akita University, 鉱山学部, 教授 (10006679)
Co-Investigator(Kenkyū-buntansha)	FUNAYAMA Hitoshi Research Assistant, Akita National College of Technology, 工業化学科, 助手 (70042322) 光行陽一郎東芝電材株式会社, 配電制御機器事業部, 主査 MATSUNAGA Toshiaki Professor, Mining College, Akita University, 鉱山学部, 教授 (40006309) MITSUYUKI Yoichiro Chief Investigator, Toshiba Electric Equipment Corp.
Project Period (FY)	1984 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥7,700,000 (Direct Cost: ¥7,700,000) Fiscal Year 1986: ¥1,100,000 (Direct Cost: ¥1,100,000) Fiscal Year 1985: ¥2,200,000 (Direct Cost: ¥2,200,000) Fiscal Year 1984: ¥4,400,000 (Direct Cost: ¥4,400,000)
Keywords	UV Oxidation / Methanol / TOC Degradation / Ultrapure Water / Recirculation / Ozone / Annular Photoreactor / 接触角 / 遠紫外線 / 循環(再生)純水 / 微量有機物分解 / 水の循環利用 / 固体表面の汚れ / 気泡塔型光反応装置
Research Abstract	The developmental research was conducted for the degradation of organic substances in water by applying the ozone treatment with UV irradiation for the recirculation of ultrapure water. Methanol was selected as a target compound since it is widely used for cleaning and resistant to decomposition. The absolute UV intensity distribution was discussed in heterogeneous annular photoreactors, and the cleanness of water was evaluated with a contact-angle method. The light source was a low pressure mercury lamp which emitted the 185nm as well as 254nm ray. The reactor was provided with a synthesized fused-silica tube (which transmitted the far UV light) for an inner wall (outside diameter of 33.0mm) and a Pyrex tube for an outside wall (inside diameter of 89.2mm). Ozone was sparged upwards as bubbles into the annulus. The self-decomposition rate of ozone was found to be facilitated by more than a hundred times with irradiation of the UV rays, by comparing the observed results of the photolytic … More and the thermal self-decompositions. The effects of the ozone and oxygen concentrations, the UV wavelength and intensity, and the residence time of liquid were examined on the degradation rate of methanol in flow system. The degradation characteristics at the high conversion region were studied with a semi-batch operation. The ozone treatment with UV irradiation had a remarkable effect. With the use of a 40W lamp, methanol was completely decomposed within 4.5 hrs under the conditions that the initial concentration of methanol was 1.24x <10^(-2)> mol/1 and the inlet concentration of ozone was 4.92x <10^(-4)> mol/1 (the flow rate of oxygen was 4 1/min) at 25゜C. The observed results were simulated with consideration that the chemical step controlled the overall heterogeneous reaction, and by assuming that the reaction order to methanol concentration was 0.5 and that methanol inhibited the decomposition of the intermediate, formic acid. The research is now undertaken to examine the characteristics of TOC degradation precisely with use of the simulated waste water. Less