Abstract

Micro-molar concentrations of aqueous 17-beta-oestradiol were 98% destroyed in 3.5 h by photocatalysis over the titanium dioxide powder immobilised on Ti-6Al-4V alloy. The concentration of oestradiol was determined by HPLC with fluorescence detection. The degradation kinetics were fitted to a Langmuir-Hinshelwood model with k(S) = 4.4 x 10(-2) mu mol dm(-3) min(-1) and K(S) = 0.347 dm(3) mu mol(-1). The pseudo-first-order rate constant (1.57 x 10(-2) min(-1)) was in line with the 50% degradation time of 40 min. The apparent quantum yield per electron was phi'(e) = 0.41%. The effect of pH on the initial rate of degradation was similar to that reported for phenol. (C) 2000 Elsevier Science B.V. All rights reserved.