Cytostatic Drug 6-Mercaptopurine Degradation on Pilot Scale Reactors by Advanced Oxidation Processes: UV-C/H2O2 and UV-C/TiO2/H2O2 Kinetics

6-Mercaptopurine (6-MP) is a commonly used cytostatic agent, which represents particular hazard for the environment because of its low biodegradability. In order to degrade 6-MP, four processes were applied: Photolysis (UV-C), photocatalysis (UV-C/TiO2), and their combination with H2O2, by adding 3 mM H2O2/L (UV-C/H2O2 UV-C/TiO2/H2O2 processes). Each process was performed variable initial pH (3.5, 7.0, 9.5). Pilot scale reactors used, using UV-C lamps as radiation source. Kinetic calculations first 20 min reaction show that H2O2 addition great importance: in experiments, highest k reached under 3.5, = 0.0094 min?1, while UV-C/H2O2, 0.1071 min?1 same pH; similar behavior observed photocatalysis, values 0.0335 0.1387 calculated UV-C/TiO2 processes, respectively, also acidic conditions. Degradation percentages here reported UV-C/H2O2 are above 90% all tested values. Ecotoxicity analysis samples taken at 60 photolysis suggests contaminant degradation by-products present higher toxicity than original compound.