The testing samples in this experiment were obtained from an acrylic fibre manufacturing companys industrial wastewater. The water was the waste of the acrylic polymerization process. The company is located in Ulsan, Korea. The concentration of acrylonitrile (AN) in the wastewater was about 25-35 mg/L. Concentrations of 3-10 mg/ L of methyl acrylate (M-35) were also found. The samples were treated by the TiO 2 /UV system and were analyzed to determine the values of COD cr , ammonia, nitrite nitrogen, and nitrate nitrogen by using an Auto Analyzer (Bran+ Luebbe, Germany) and a TOC (Tekmar Dohrmann, USA). Various reaction parameters, such as TiO 2 content, light intensity and wavelength, and the number of UV lamps were varied and their effects or decomposition efficiency were analyzed. The adsorption onto TiO 2 surfaces by organic materials in the wastewater was negligible. The reaction-rate constant was also calculated. The reaction rate constant for the G36T6L lamp at both 185 nm and 256 nm was 0.0661 hr −1 which is 1.3 times higher than that of the TUV36T5 lamp at 256 nm. While the reaction rate was increased by increasing the surface area of the photocatalyst, the excess photocatalyst blocked the light sources, causing a photoenclosure effect. The stability of the treated wastewater was greatly increased because the elimination of the concentration of nitrite was followed by an increase in the concentration of nitrate. Generally, the ratio of BOD 5 /COD cr is used as the criterion for determining biodegradability. A ratio of 0.3 is needed for biological degradation. The ratio of the treated wastewater increased to 0.5 after 12 hours of reaction. The ratio increased to 0.8 after 20 hours.
The cleaning efficiency of EO (ethylene oxide) 8~9 mole was about 78-80%, it is the best. The highest cleaning efficiency for each EO mole concentration is as follows. The cleaning efficiency was 97% in the surfactant of 4.8% EO 5 mole, the cleaning efficiency was 97% in the surfactant of 7.7% EO 8 mole, and 68% in the surfactant of 7.7% EO 10 mole. The cleaning efficiency was measured using a surfactant with various EO mole. All detergents were tested at 20% surfactant concentration and EO 8 and EO 9 showed the highest cleaning power. In experiments using 8 mole of EO surfactant NPE8, the highest cleaning power was obtained at surfactant concentration of 7.7%. To determine the cause of this, the electrical conductivity of the solution was measured at the concentration of NPE8 at 1.6%, 4.8%, 7.7%, 14.4% and 20%, respectively. After washing the test plate with NPE8, the detergent remaining on the surface of the test plate was analyzed by FT / IR, and it was found that the detergent did not remain.
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