광반응 및 광촉매 반응을 이용한 simazine으| 분해 및 독성저감에 관한연구

A Study on the Degradation and the Reduction of Acute Toxicity of Simazine Using Photolysis and Photocatalysis

The photocatalysis degradation of simazine, s-triazine type hεrbicide was carried out using circulating photo reactor systems. In order to search for the effective method to mineralize this compound into environmentally compa뻐le products, this study compared the removal efficiencies of simazine by changing various p따ameters. First, under the photocatalytic condition, simazine was more effectively degraded than by photolysis and Ti02 only condition. With photocatalysis, 5 mgll sÎmazine was degraded to approximate\y 90% within 30 min, and completely degraded after 150 min. Ionic byproducts such as N02-, N03-, and C\- were detected from the photocatalysis of simazine, howεver， the recoveries were poor, indicating the presence of organic intermediates rather than the mineralization of sÎmazine dnring photocatalysis. Two bioassays using V. fischeri and D. nwgna were employed to measure the toxicity reduction in the reaction solutions treated by both photocatalysis and photolysis. Simazine and its photocatalysis treated water did not exert any significant toxicity to V. cheri， marine bacterium. However, the acute toxicity t， using D. nwgna indicat， that initiaJ acute toxicity (EC50 = 57.30%) was completely reduced (EC50 = 100%) after 150 min under both photocatalysis and photoysis of simazine. This results indicates that photocatalysis and photolysis of simazine reduced the acute toxicity through mineralization.