Study On The Oxidative Degradation Of Representative Environmental Enstrogens By Manganese Dioxide

The pollution of environmental estrogen has become another global environmental problem,which follows the ozone layer destruction and greenhouse effect.More and more attention all over the world has been paid on the research and treatment of environmental estrogens.Therefore, it is very important to conduct some related studies,including identification and monitoring,ecological effect and pollution control of environmental estrogens.First,a method for the determination of estrone(E1),estradiol(E2), ethinylestradiol(EE2) and estriol(E3) in wastewater was developed using solid-phase extraction(SPE) - derivatization - gas chromatography/mass spectrometry(GC/MS).The sample was extracted by an SPE column and derivatied by bis(trimethylsilyl) trifluoroacetamide(BSTFA),then analyzed by GC-MS.The detection limits were 1.8～4.7 ng/L,the relative standard deviations were 2.3%～9.1%(n=8),and the recoveries of above four environmental estrogen compounds were ranged from(94.0±2.9)%to (101±3.8)%.It was concluded that the established method can be applied to determination of the estrogenic compounds in wastewater samples successfully.The method was used for determination the concentration of environmental estrogens in the waste water,which taken from a pharmacy factory and two urban sewage plants.It was found that E1 and EE2 could be detected in the pharmacy factory,and some other environmental estrogens were detected in the sewage plants.The results demonstrated that the traditional treatment process should be improved.Then,the oxidative transformation of E2 and EE2 by theδ-MnO₂ was investigated in batch experiments.The results suggested that E2 and EE2 could be degraded byδ-MnO₂,and the oxidation reaction deviated from the pseudo-first-order kinetics at a constant pH and with an enough excess ofδ-MnO₂,while a good linear fit(R²=0.97) can be obtained at the first 30 min,which is indicative of pseudo-first reaction kinetics in the first stage.δ-MnO₂ dosage had a positive effect on oxidative transformation of E2 and EE2.The pH values had a negative effect on E2 and EE2 degradation.The presence of metal ions and carboxylic acids had some inhibitory effect on r_init as a result of the decreased number of active surface sites in the presence of cosolutes.Finally,the probably products and its estrogenic effect were examined in E2 oxidative degradation with MnO₂.Two products,estrone(E1) and 2-hydroxyestradiol,were detected by gas chromatography coupled with mass spectrometry(GC-MS),and the probabal degradation pathway was proposed.Furthermore,the determination of estrogenic activity was used yeast estrogen screen.The datas showed that after 8h reaction byδ-MnO₂, the estrogenic effect of E2 and EE2 reduced by about 60%.This study may provide useful information to better understanding the fundamental knowledge relevant to the interaction of organic pollutants and manganese oxides in natural environment.