Photocatalytic oxidation of cytostatic drugs by microwave-treated N-doped TiO2 under visible light

BACKGROUND5-Fluorouracil is one of the most commonly used cytostatic drugs worldwide. However, the toxicity and persistence of 5-fluorouracil in the environment have recently received considerable attention.In this study, 5-fluorouracil removal was performed by photocatalytic oxidation with microwave-treated N-doped TiO2 under visible light. RESULTSThe microwave-treated N-doped TiO2 removed 5-fluorouracil with a higher degradation efficiency than N-doped TiO2 synthesized with the traditional thermal treatments. The most efficient N-doped TiO2 (N6) was synthesized using 1 M NH4OH pre-immersion and a 3 h 180 degrees C microwave treatment, followed by 55 degrees C calcination for 6 h. The photocatalytic degradation of 5-fluorouracil achieved 88.8% removal within 20 h of treatment by N6 under visible light, which is higher than that obtained by Degussa P25 TiO2 (61.5%). Higher concentrations of NH4OH and longer calcination times resulted in decreased 5-fluorouracil degradation; the particle size of the synthesized N-doped TiO2 increased after calcination. The surface area decreased while the pore volume and pore size increased after synthesis. Furthermore, the basicity of the sites on the synthesized N-doped TiO2 decreased after calcination. CONCLUSIONThis study, for the first time, reported that microwave-assisted treatment for N-doped TiO2 synthesis effectively removed 5-fluorouracil and cyclophosphamide compared with traditional thermal treatment. (c) 2014 Society of Chemical Industry