Synergetic effect of packed-bed corona-DBD plasma micro-reactor and photocatalysis for organic pollutant degradation

Abstract

A packed-bed Corona-DBD hybrid plasma micro-reactor is coupled with a novel heterogeneous photocatalyst-AgFeO2/CNTs/TiO2 for methyl orange degradation. The corona nature of the plasma produces a high concentration of active species, yet maintaining a homogeneous discharge owing to the dielectric barrier nature of the reactor. The submicron channels in the plasma reactor created by glass beads increased dielectric strength and simultaneously produced high energy streamers, which increased the ozone generation by 24%. The AgFeO2/CNTs/TiO2 photocatalyst gave stretched adsorption edge (400–500 nm), reduced bandgap energy (2.3 eV), facilitated degradation under visible light, and provided the additional advantage of the Fenton process, leading to the OH. formation. The three reaction systems were investigated and compared for MO degradation-photocatalysis, plasma reactor and integrated plasma photocatalysis reactor which gave 1.2%, 50.8%, and 98% removal in 2 min respectively. The solution pH, dosage, and loading of AgFeO2 in photocatalyst was investigated. The integrated plasma photocatalysis gave 95% degradation of 250 ml solution of 30 ppm methyl orange at pH 3 with 0.5 g/l of 2.5% AgFeO2/CNTs/TiO2 photocatalysis in 2 min. The integrated plasma photocatalysis reactor increased the number density of active species, particularly, OH. in wastewater which makes it a good choice for azo dyes degradation.