Ozonation of estrone, estradiol, diethylstilbestrol in waters

The ozonation of three environmental endocrine disrupters (EDCs), estrone(E-1), estradiol(E-2). and diethylstilbestrol (DES), in aqueous solutions were investigated. Batch experiments were carried out to research the effect of initial EDCs concentrations, initial pH values and ozone dosages on the degradation efficiency. At pH 9.0, the degradation efficiency of estrone (E-1) reached to 94% after 8 min; diethylstilbestrol could be totally degraded after 6 min, and even estradiol was completely degraded after only 4 min. After 6 min for ozonation, the degradation efficiency of E-2 was nearly 48% with ozone dosage of 0.13 mg min(-1). Compared with the ozone dosage of 0.38 mg min(-1), E-2 entirely degraded after 6 min. Ozone dosage on degradation of E-1 was in a similar way. DES had analogous rule. At four different concentration solutions (5-20 mg L-1) of EDCs exposed to ozone, the higher the initial EDCs concentration, the lower EDCs degradation efficiency was obtained. During the ozonation process, the rapid decreasing of pH and the sharp increasing of electrical conductivity indicated the higher polarity by-products were produced during ozonation, which was confirmed by high performance liquid chromatography (HPLC) analysis. The results could provide some useful information for the potential treatment of EDCs by ozonation in waters. (C) 2009 Elsevier B.V. All rights reserved.