| Environmental endocrine disruptors (EDs) are defined as exogenous substances that interfere with the synthesis, secretion, transport, binding, action, or elimination of natural hormones in the body that are responsible for the maintenance of homeostasis, reproduction, development, and/or behavior. Since the American scientists Colborn et al. published their famous book "Our Stolen Future" in 1996, the researches on the environmental endocrine disruption issue have been promoted greatly. At present, there are at least 50 to 70 compounds suspected to be of estrogenic activity. However, no statistic result has been reported on the exact amount of the EDs. Among those identified EDs, estrogens are the most close to human that have been studied less before but drawn much more attentions in the recent years.Among the research fields of the EDs, the treatment method development is one of the important aspects for EDs study. Our group has been engaged in researches on the photochemical properties and application to water pollution control of different ferric species including Fe(Ⅲ)-OH complexes, Fe(Ⅲ)-polycarboxylate complexes, Ferric oxides and Fe(Ⅲ)-humic acid complexes. This thesis is focused on the photodegradation of four estrogens: diethylstilbestrol (DES), estradiol (E2), estrone (El), 17a-ethynyl estradiol (EE2) in the Fe(Ⅲ)-H2O2 system and the efficiencies and the mechanisms.At different time intervals during the radiation, the concentrations of estrogens were analyzed using high pressure liquid chromatography (HPLC). The effects of pH values, H2O2 concentration, and the initial concentration of estrogens on the photodegradation were investigated. The kinetics analysis of the photodegradation reaction was performed according to the pseudo first-order law. And through the analysis of the minrelization product(CO2), We can know the mineralization degree and make sure of the degradation efficiencies of the estrogens. The main results and conclusion are presented as below.1. It is confirmed that the three estrogens studied in this work can be photo- oxidized and degraded in the Fe(Ⅲ)-H2O2 system. The photodegradation efficiencies are dependent on the pH value and H2O2 concentration of the system, with higher efficiency at Ph 3-3.5 and high H2O2 concentraston. The photodegradation reactions obey the law of pseudo first-order reaction at the concentration over the range of 10.040.0mg/L of DES, 5.020.0μmol/L of E2 and 2.510.0μmol/L for El. The photodegradation rates decreasewith increasing the initial concentrations of estrogens. For lO.Omg/L DES, E2 and El, the observed photodegradation rate coefficients (&Obs) are 0.0421, 0.00626 and 0.0057 min"1 respectively.2. Through the measurement of the photodegradation product CC^of the estrogens in the Fe(Ⅲ)-H2O2 system, we know the degradation degree of the estrogens, and predict the possible photodegradation mechanism. The mineralization degree of the DES is very high, on the contrary, the mineralization degrees of the E2 and El are lower. The reasons may be the mineralization occurs only at the benzene ring, the other alkyl rings are not mineralized.3. In order to realize if the photodegradation behavior of the estrogens mixture has the difference with the alone estrogen photodegradation behavior, and to see the other important estrogen EE2, the four estrogens mixture is photo- oxidized and degraded in the Fe(Ⅲ)-H2O2 system. The result indicates that the degradation rate of the four estrogens in the order from high to low is DES, E2, EE2, El.
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