Degradation of thiamethoxam in water by the synergy effect between the plasma discharge and the TiO2 photocatalysis

Abstract

TiO2 loaded on the honeycomb ceramic was tentatively introduced into dielectric barrier discharge (DBD) in a radial-flow configuration, for plasma-induced photocatalytic degradation of a model organic pollutant thiamethoxam in water. The solution was made to flow as a film over the surface of the honeycomb ceramic, whose hydrophilic force kept the water surface undisturbed by the electrical discharge. This characteristic enabled a reduction of the discharge gap. The results indicated that rate constant of thiamethoxam degradation, energy utilization efficiency of thiamethoxam removal and TOC removal were significantly enhanced due to the synergy effect between the plasma discharge and the TiO2 photocatalysis. The system could adapt to a wide range of liquid conductivity. The TiO2 film was calcined at 500°C and the crystal structure of the TiO2 showed no change after use. Higher concentration of H2O2 and ·OH were obtained.