Photocatalytic treatment of metoprolol and propranolol

The aim of this study was to investigate and compare the effect of an advanced oxidation process, the photocatalysis, on the removal of two emerging contaminants in water; the pharmaceuticals metoprolol tartrate salt (MET) and propranolol hydrochloride (PRO). The analyzed parameters were pharmaceutical removal, total organic carbon (TOC), specific UV absorbance (SUVA), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), toxicity and formed intermediates. Besides, the optimal photocatalyst concentration was determined. Afterwards, photocatalytic experiments were carried out with 0.4 g L−1 of TiO2 as suspended catalyst and a Xenon lamp (Philips XOP 15-OF, 1000 W) as irradiation source. According to the results, after 240 min of irradiation, a removal near to 94% was obtained for both compounds. After 360 min of treatment, a mineralization degree in the vicinity of 55% was observed. Biodegradability index (BOD5/COD) improved from values close to zero (raw solution) up to 0.4 and 0.6 for MET and PRO. The acute toxicity measured by the inhibition percentage of bioluminescence from Vibro fischeri indicates that the photocatalytic treatment of this kind of compounds promotes toxicity reduction. According to the experimental results, photocatalysis appears as a useful technique for the degradation of both β-blockers.