Treatment of aquatic medium containing common and emerging contaminants using an aero-electrochemical process based on graphite cathode and three metal oxides alloy as anode: Central composite design and photo/sono-enhancement

An aero-electrochemical advanced oxidation process (aero-EAOP) equipped with graphite cathode and dimensionally stable anodes was utilized for the treatment of aquatic media containing common and emerging contaminants. Among various anode materials, the application of Ti/RuO₂/IrO₂/SnO₂ anode resulted in the highest effectiveness. Central composite experimental design (CCED) was used to attain the optimum operational parameters in terms of chlorine generation. Simultaneous decolorization and ammonium removal by the aero-EAOP process were investigated. Accordingly, the decolorization efficiency of 94%, along with the ammonium removal of 65.2%, was obtained within 30 min. Implementation of ultrasound and UV irradiation resulted in the complete decolorization within 25 and 20 min, respectively. In comparison, the influence of ultrasound and UV irradiation on the ammonium removal by the aero-EAOP reactor was not remarkable. Mineralization efficiency of 75.1% was obtained during the short reaction time of 30 min. With increasing hydraulic retention time (HRT) from 2 to 20 min, decolorization efficiency increased from 12.0 to 55.7% and ammonium removal efficiency increased from 16.6 to 37.8%, respectively. The complete degradation of amoxicillin (AMX) and tetracycline (TC) antibiotics were achieved within 25 and 30 min, respectively. The degradation efficiencies of ibuprofen (IBP), acetaminophen (APAP) and endocrine disrupting compound of bisphenol A (BPA) were obtained to be 58, 66 and 78% within 30 min, respectively. Photo-assisted aero-EAOP was more efficient than the aero-EAOP in degrading target emerging pollutants.