UV-C radiation based methods for aqueous metoprolol elimination

The endocrine disruptor metoprolol has been oxidised in aqueous solution by means of the systems UV-C, UV-C/H2O2, UV-C/percarbonate, UV-C/monopersulfate, UV-C/TiO2, UV-C/H2O2/TiO2 and photo-Fenton. From simple photolysis experiments the quantum yield of metoprolol has been calculated (roughly 5 × 10−3 mol Einstein−1 at circumneutral pH). Addition of free radicals promoters significantly enhanced the metoprolol depletion rate. Mineralization degree was negligible when no promoter was added, while low values were achieved in the presence of either inorganic peroxides or titanium dioxide. The combination of radiation, hydrogen peroxide and TiO2 increased the mineralization level up to values in the proximity of 45–50% under the best conditions investigated. The photo-Fenton process was the best system in terms of total oxidation (mineralization degree 70%) when optimum conditions were applied.