UV-driven removal of tricyclic antidepressive drug amitriptyline using TiO<inf>2</inf> and TiO<inf>2</inf>/WO<inf>3</inf> coatings

Abstract

Photocatalytic degradations of tricyclic antidepressive amitriptyline (AMI) in aqueous solutions under UV irradiation were performed using TiO2 and TiO2/WO3 coatings, as photocatalysts. Coatings were formed on a pure titanium substrate using plasma electrolytic oxidation (PEO). The effects of chosen synthesis parameters on structural properties of prepared coatings have been investigated using micro-Raman spectroscopy and non-contact atomic force microscopy. Raman scattering measurements showed that coatings contain different amounts of crystalline anatase TiO2 and monoclinic WO3−x phases, as well as amorphous and/or disordered phases of both oxides. Also, results indicated that coatings’ surface become more disordered and inhomogeneous with increasing duration of the PEO. The coating T/W(45 s) prepared during 45 s of PEO has shown the highest efficiency in the UV-driven removal of AMI. T/W(45 s) showed slightly decrease in photodegradation efficiency after four successive runs. The results showed that the degradation of AMI led to the formation of ionic by-products (nitrite, nitrate, ammonium ion, acetate, and formate), whereas degree of mineralization was the highest (38.8%) using coating T/W(45 s) after 120 min of irradiation. Also, there was no significant toxicity observed after irradiation of AMI solutions using different coatings on four mammalian cell lines: rat hepatoma, mouse neuroblastoma, human colon adenocarcinoma, and human fetal lung.