Electron beam application to fluoxetine and surfactant mixture degradation, with persulfate, and toxicity approach

Abstract

Electron beam irradiation (EBI) is an essential tool for removing organic pollutants from water and wastewater. Depending on the type of effluent being treated, this process can be combined with persulfate to enhance removal efficiency. The simultaneous effects of persulfate (PS) initial concentration and absorbed dose on the degradation of the antidepressant fluoxetine were investigated: a binary mixture (fluoxetine and surfactant sodium dodecyl benzene sulfonate) was treated, following a Doehlert experimental design. Toxicity tests were also conducted using Daphnia similis . Additionally, the surfactant aqueous solution was treated by an electron beam accelerator. The results showed that 90.1 ± 1.1 % of fluoxetine in the mixture was removed at a dose of 5.0 kGy. The combination of irradiation with persulfate (PS) significantly improved fluoxetine removal compared to EBI, consistently achieving over 90 % removal. However, higher concentrations of persulfate (2.5 mmol L−1) did not increase fluoxetine removal. Toxicity tests were performed on samples treated under the optimized conditions ([PS]0 = 1.1 mmol L−1; absorbed dose - 4.5 kGy) and revealed an increase in Daphnia similis toxicity, suggesting the formation of toxic byproducts. Concerning the data obtained for the aqueous solution of irradiated surfactant, more than 90 % degradation was achieved in the evaluated doses (2.5 and 5.0 kGy), resulting in a 70 % reduction in toxicity at 5.0 kGy.