Photooxidation of the antidepressant drug Fluoxetine (Prozac®) in aqueous media by hybrid catalytic/ozonation processes

This article examines the oxidative disposal of Prozac® (also known as Fluoxetine, FXT) through several oxidative processes with and without UV irradiation: for example, TiO2 alone, O3 alone, and the hybrid methods comprised of O3 + H2O2 (PEROXONE process), TiO2 + O3 and TiO2 + O3 + H2O2 at the laboratory scale. Results show a strong pH dependence of the adsorption of FXT on TiO2 and the crucial role of adsorption in the whole degradation process. Photolysis of FXT is remarkable only under alkaline pH. The heterogeneous photoassisted process removes 0.11 mM FXT (initial concentration) within ca. 60 min with a concomitant 50% mineralization at pH 11 (TiO2 loading, 0.050 g L−1). The presence of H2O2 enhances the mineralization further to >70%. UV/ozonation leads to the elimination of FXT to a greater extent than does UV/TiO2: i.e., 100% elimination of FXT is achieved by UV/O3 in the first 10 min of reaction and almost 97% mineralization is attained under UV irradiation in the presence of H2O2. The hybrid configuration UV + TiO2 + O3 + H2O2 enhances removal of dissolved organic carbon (DOC) in ca. 30 min leaving, however, an important inorganic carbon (IC) content. In all cases, the presence of H2O2 improves the elimination of DOC, but not without a detrimental effect on the biodegradability of FXT owing to the low organic carbon content in the final treated effluent, together with significant levels of inorganic byproducts remaining. The photoassisted TiO2/O3 hybrid method may prove to be an efficient combination to enhance wastewater treatment of recalcitrant drug pollutants in aquatic environments.

► We examine the advanced oxidation process for the antidepressant drug Fluoxetine which causes aquatic drug pollution.
► The optimal experimental factors of the hybrid procedure using ozone together with hydrogen peroxide in the aqueous titanium dioxide dispersion under UV-exposure were found.
► The hybrid procedure enhances the degradation rate for aromatic ring cleavage, dissolved organic carbon defluorination and mineralization.
► The photodegradative pathway is revealed to identify the intermediate products by TOF-MS technique.