Propranolol hydrochloride degradation using La@TiO2 functionalized with CMCD

Propranolol hydrochloride can be considered a persistent and bioaccumulative pharmaceutical in the environment. This drug and its by-products are potentially toxic and have adverse effects, since these compounds have been associated with endocrine-disrupting effects, reproductive deficiencies, embryo abnormalities and pericardial oedema. TiO₂–La 0.05%–carboxymethyl-β-cyclodextrin (CMCD) nanoparticles were successfully prepared by a simple two-step method, which consists of sonification and functionalization. The characterization analyses reveal that lanthanum is dispersed on the semiconductor surface, probably forming Ti–O–La bonds, which can induce oxygen vacancies and surface defects that effectively restrain the recombination of photogenerated electron/holes pairs. The efficiency of TiO₂–La 0.05%–CMCD samples in degradation of propranolol under UV-light irradiation is higher than that of pristine TiO₂ within 20 min reaction, probably due to complex formation between the β-blocker and the oligosaccharide, which allows us to propose a photocatalytic mechanism based on the formation of intermediates and competition of these compounds to the radicals and CMCD cavities.