Photocatalytic degradation of 17β-oestradiol, oestriol and 17α-ethynyloestradiol in water monitored using fluorescence spectroscopy

Photocatalytic degradation of the natural oestrogens 17β-oestradiol and oestriol and the synthetic oestrogen 17α-ethynyloestradiol in water were investigated. The reactions were carried out in a quartz coil reactor coated internally with titanium dioxide (Degussa P-25). Degradation by UV light alone was also investigated. Reactions were monitored using fluorescence spectroscopy. The effect of initial concentration and the effect of light intensity on the photocatalysis and photolysis of 17β-oestradiol in water were also investigated. The results showed that photocatalysis and photolysis are capable of degrading all three oestrogens in water. Photocatalysis is much more effective than UV light alone and all reactions follow pseudo first order kinetics. The rate was found to be proportional to the square root of light intensity for photocatalysis of 17β-oestradiol. The relationship between light intensity and the rate of degradation by photolysis is linear up to a point when it starts to level off.