Comparison of Acid Orange 7 Degradation in Solution by Gliding Arc Discharge with Different Forms of TiO2

Plasma catalysis for wastewater treatment is an emerging advanced oxidation process. In the present work, the performances of photocatalyst nanoparticles-assisted and immobilized photocatalysts-assisted gliding arc discharge (GAD) plasma reactors have been tested with the acid orange 7 (AO7) solution selected as the target wastewater. Immobilized photocatalysts of gamma-Al2O3TiO2 were made by a solgel and immersion method with activated alumina balls used as carriers. Through the analysis of XRD, it was found that TiO2 surface was mainly anatase crystal-based. Compared with TiO2 nanoparticles, the immobilized catalysts did not have the defects of inhibiting GAD which catalysts would be caused by suspended, therefore, showing a better catalytic performance. In the available range of dosage of catalysts, the catalytic effect of gamma-Al2O3TiO2 was increased with dosage. When the catalyst amount was 10.0g, COD of the target solution decreased with a rate constant of 0.0487min-1 and an abatement rate of 39.2% in 40?min with TiO2 nanoparticles (0.375g.?L-1) as catalysts, but was decreased with a rate constant of 0.0573?min-1 and an abatement rate of 43.6% in 40?min with gamma-Al2O3TiO2 as catalysts. The system of plasma and gamma-Al2O3TiO2 catalysts is suitable for high concentration organic wastewater treatment and, moreover, can degrade and mineralize wastewater effectively.