Comparison of acid orange 7 degradation in solution by gliding arc discharge with different forms of TiO 2

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.