Power dependence of reactive species generation in a water falling film dielectric barrier discharge system

The short-lived and long-lived reactive species generated in plasma-liquid interactions determine their potential applications in wastewater purification and plant growth stimulation. In this work, plasma-generated reactive species including hydroxyl radicals (∙OH), hydrogen peroxide (H2O2), ozone (O3), hydronium (H3O+), and nitrate (NO3-) were quantified in a water falling film dielectric barrier discharge system. The reaction kinetics of short-lived ∙OH were analyzed based on the quantification of ∙OH and degradation of salicylic acid, focusing on the contribution and utilization of ∙OH. The interconversion of ∙OH with H2O2 and O3 was also calculated. The accumulation rates of H3O+ and NO3- indicated the potential of this dielectric barrier discharge system in sustainable fertilizer production. In addition, the toxicity prediction of salicylic acid degradation intermediates and the cultivation of soybean seeds verified the feasibility of plasma-liquid interactions in organic wastewater recycling.