PHOTOCATALYTIC OXIDATION OF NON-STEROIDAL ANTI-INFLAMMATORY DRUGS

Abstract

Pharmaceuticals diclofenac and naproxen belong to class of non-steroidal anti-inflammatory drugs (NSAIDs). These substances are very often found in outlets of WWTP or in surface waters, because among all classes of pharmaceuticals, they are frequently prescribed and purchased. These substances have by their nature a strong biological effect, so non-target organisms are affected. For example diclofenac causes cytological malformations of liver tissue within a concentration 28 μg/L (O. mykkis). Sensitive organisms to naproxen are crustaceans, where the EC50 for (C. dubia) is 330 μg/L, but degradation products of this drug are significantly more toxic. EC50 for degradation products of naproxen to C. dubia are less than 100 μg/L. Diclofenac and naproxen (500 μg/L) were from model water samples removed by heterogeneous photocatalysis in 4L batch reactor. After irradiation of the catalyst, the system produces •OH radicals, which causes destruction of the organic substance. As the catalyst used was 0.5 g/L titanium dioxide (TiO2, Precheza a.s.). As a source of UV radiation was used UV LED diode Luminus, with peak wavelength at 365 nm. At the same time the effect of hydrogen peroxide (H2O2) or effect of pH was determined. Samples were preconcentrated by solid phase extraction (SPE) and analyzed by high performance liquid chromatography (HPLC). At the same time characteristics and capability of pharmaceutical removal from inlet of WWTP were discussed.