Sonoelectrochemical oxidation of carbamazepine in waters: optimization using response surface methodology

BACKGROUND The decomposition of carbamazepine (CBZ) in synthetic solution and in municipal effluent was investigated using a sono-electrochemical reactor. Sono-electrolysis was conducted using two concentrical electrodes installed in a cylindrical reactor containing a ceramic transducer. RESULTS CBZ concentration (Cₒ=10 mg L⁻¹) optimally diminished up to 90% by applying a current intensity of 4.86 A for 177 min and by imposing an ultrasound power of 38.29 W. The optimal conditions were subsequently applied for tertiary treatment of municipal wastewater effluent contaminated with 10 µg CBZ L⁻¹. The reported removal efficiencies of CBZ, TOC, COD and colour were 93%, 60%, 93% and 86%, respectively. Likewise, the toxicity was completely removed (bacterium Vibrio fisheri) from the municipal wastewater effluent (>96%). CONCLUSIONS The advantages of coupling ultrasonication and electrooxidation (US-EO) treatment for CBZ removal were demonstrated. An experimental design methodology based on response surface methodology was applied to determine the optimal experimental conditions in terms of cost/effectiveness of removal.