Catalytic use of TiO2 nanowires in the photodegradation of Benzophenone-4 as an active ingredient in sunscreens.

Water contamination has compromised the quality of this resource during the last years with the presence of persistent organic pollutants. Because of the resistance of these compounds to degradation, several advance oxidation techniques have been proposed. In this study, we report the employment of an advance oxidation technique in the degradation of benzophenone-4 (BP-4), using TiO2 as catalyst, which was obtained following a fast-hydrothermal method. TiO2 nanowires (TiO2NWs) were fully characterized considering the morphology, elemental composition, oxidation states, vibrational modes and crystalline structure with SEM and TEM, EDS, XPS, FTIR and XRD, respectively. The photocatalytic degradation was carried out using a home-made photoreactor under slightly acidic conditions achieving an average of 90% removal. It was determined that the photocatalysis is the most probable route of degradation since the photolysis or catalysis procedures produce negligible contributions. An apparent kinetic constant of 1.29 × 10-2 min-1 was determined, according to a pseudo-first order reaction.