UV-C photolysis of endocrine disruptors. The influence of inorganic peroxides.
Norfloxacin, doxycycline and mefenamic acid have been photolysed with UV-C radiation (254 nm) in the presence and absence of inorganic peroxides (hydrogen peroxide or sodium monopersulfate). Quantum yields in the range (1.1-4.5)x10(-3) mol Einstein(-1) indicate the low photo-reactivity of these pharmaceuticals. Inorganic peroxides considerably enhanced the contaminants conversion, although no appreciable mineralization could be obtained. A simplistic reaction mechanism for the hydrogen peroxide promoted experiments allowed for a rough estimation of the rate constant between hydroxyl radicals and norfloxacin (k>1 x 10(9)M(-1)s(-1)), doxycycline (k>1.5 x 10(9)M(-1)s(-1)) and mefenamic acid (k>11.0 x 10(9)M(-1)s(-1)).