抄録
Trichloroethylene (TCE) had been used as a solvent for dry cleaning and is still used to remove grease from metal parts and so on. However it has recently caused a serious problem that soil and underground water are polluted by TCE. TCE has various effects on human health. For example it may cause headaches, lung irritation, impaired heart function, etc. Therefore TCE concentration in soil is regulated by environmental quality standards for soil and so on. Because of these reasons, purification of contaminated soil or underground water is a matter of great urgency. In situ treatment technologies so far used are mainly bio-remediation and pumping and aeration method. Bioremediation is major method in the United States. But it often causes secondary pollution and it requires long treatment period. In Japan, pumping and aeration method is normally used. But it can't be applied to widespread polluted soil. In situ treatment technologies are required that is applicable to stable pollutants, under various polluted conditions with various ranges of TCE concentration. One of the technologies that satisfy these requirements is chemical oxidation. We noticed Fenton's reaction, which is usually used for oxidation of organic compounds for degradation of TCE. In this study, we investigated the kinetics of degradation of TCE by Fenton's reaction and identified decomposed products. The experiments showed that reaction rate is first-order for TCE and iron, respectively, and half-order for hydrogen peroxide. Major decomposed product was chloride ion, and dichloroacetic acid was slightly produced. In addition we supposed degradation pathway of TCE in Fenton's reaction.
