Sonophotocatalytic (1.7 MHz, 254 nm) destruction of Bisphenol-A in aqueous solutions

Abstract

Bisphenol A (BPA) an organic compound largely used in the plastic industry as a monomer. The micropollutant BPA (43.8 μM) was employed under conditions of high-frequency ultrasound (1.7 MHz, 25 W) and ultraviolet radiation (254 nm). To enhance degradation a Fenton-like oxidation system was used, including persulfate as an oxidizing agent and ferrous iron (Fe (II))) as a catalyst. Experiments were carried out in a flow sonophotoreactor, flow rate 0.5 l/min. The progress of the treatment of Bisphenol-A solution has been monitored in terms of reduction in the concentration (HPLC) and dissolved organic carbon (DOC). A large synergistic effect (2.4) was shown in the oxidation of Bisphenol-A from the combined effect of two directed at each other sources of ultrasound. The efficacy of combined approaches was generally higher than individual treatment methods of sonolysis (87%) and photolysis (15%) in 240 min of treatment. Complete oxidation of BPA is achieved in the {UV/US/Fe2+/S2O82-} system in 120 minutes, however, mineralization reaches (50%), possibly due to the lack of an oxidizing agent. The reaction rates of Bisphenol A degradation and mineralization increase in the order: {UV}