An innovative combination of anodic oxidation using Cu/SnO2–Sb2O5 rotating cylinder anode with TiO2 photocatalytic process for treating hospital wastewater

Abstract

Treatment of hospital wastewater was achieved successfully using a novel combined process composed of an anodic oxidation with Cu/SnO₂–Sb₂O₅ rotating cylinder anode and a photocatalysis process with titanium oxide nanoparticles. Cu/SnO₂–Sb₂O₅ anode and TiO₂ nanoparticles were characterized by x-ray diffractometer (XRD) and scanning electron microscopy (SEM). The feasibility of the combined process was evaluated using response surface methodology (RSM). Three operating factors were studied namely current density (10–20 mA/cm²), pH (4–8), and TiO₂ dosage (0.3–0.7 g/L). Results showed that current density has the major effect on the COD removal with a contribution percent of 40 %. The optimal conditions were current density of 20 mA/cm², pH of 4, and TiO₂ dosage of 0.7 g/L in which COD removal of 91.2 % was achieved with claiming a total electrical energy (EEC_T) of 39.41 kWh/ m³. An interesting synergistic effect with a synergy of 21.26 % was recognized in the combined process due to the high productivity of hydroxyl radicals resulting from the interaction between the individual processes. Results confirmed that coupling anodic oxidation with photoctalysis is a promising method for treating hospital wastewater.