Synergistic effect of dielectric barrier discharge plasma and Ho-TiO2/rGO catalytic honeycomb ceramic plate for removal of quinolone antibiotics in aqueous solution

Abstract A novel and efficient dielectric barrier discharge (DBD) plasma-catalytic system was studied, and Ho-TiO2/rGO catalytic honeycomb ceramic plates were successfully prepared via a sol-gel method. Norfloxacin (NOR) and gatifloxacin (GAT) were selected as typical quinolone antibiotics to evaluate the catalytic oxidation activity of the system. The synergistic effect of Ho3+ and rGO makes the modified TiO2 exhibit excellent photocatalytic activity. Moreover, the physical and chemical properties of the catalysts were characterized by various characterization techniques. The effects of different initial power, pH, conductivity, pollutant concentration, etc. on the degradation efficiency of quinolone antibiotics have also been investigated. The results show that the DBD plasma coordinated with a photocatalytic system possessed higher catalytic oxidation activity. The possible degradation pathways were derived from the main intermediate products by HPLC-MS analysis. It can be concluded that •OH, h+, and •O2− were the major active radicals in the system, and these radicals cooperated with active substances (O3 and H2O2) to complete the degradation of quinolone antibiotics. The potential DBD plasma synergistic photocatalysis mechanism was proposed according to characterization and experimental results. This work provides a simple and feasible research direction for the synergy of different technologies to remove organic pollutants in water.