[Oxidative transformation of 17beta-estradiol at the interface of delta-MnO2 and water]

Abstract

The oxidative transformation of 17beta-estradiol (E2) by the delta-MnO2 was investigated in batch experiments, and the influence of pH and delta-MnO2 dosage on the reaction process was studied. The results suggested that E2 could be degraded by delta-MnO2, and the oxidation reaction deviated from the pseudo-first-order kinetics at a constant pH and with an enough excess of delta-MnO2. Delta-MnO2 dosage had a positive effect on oxidative transformation of E2. When c (E2) : c (MnO2) = 1:100, the delta-MnO2 dosage was enough for E2 degradation, and the removalrate of E2 was above 90% after 8h reaction. The pH value had a negative effect on E2 degradation. When at pH 4.0, E2 concentration was decreased sharply and removal rate reached 95% after 0.25 h reaction, while E2 was disappeared by 80% at pH 6.8 and by 75% at pH 9.0 even after 1 h reaction. Two products, estrone (E1) and 2-hydroxyestradiol, were detected by gas chromatography coupled with mass spectrometry (GC-MS), and the probable transformation pathway was proposed.