Understanding the Plasma Chemistry of Gas-Liquid Interfaces: Degradation of Rhodamine B by a Dielectric Barrier Discharge Plasma Jet
Mentor: Dr. Selma Mededovic
Department: Chemistry and Biomolecular Engineering
Electrical discharges in gas-liquid environments are under intensive investigation for many applications in biomedical, environmental, and chemical engineering. Examples include bacterial inactivation, purification of water containing chemical impurities, food processing, and blood coagulation. Chemical and physical processes by which gas plasmas induce changes in chemical and biological components in water are not well understood. Though a limited number of studies conducted in air and oxygen plasmas above water surface (mainly for the purpose of sterilization) identified reactive oxygen and nitrogen species responsible for bio-decontamination, the reactions leading to the formation of these species, the location of their formation (gas vs. gas-liquid interface), and chemical and physical processes occurring at the plasma-liquid interface are largely unknown. The objective of this project is to develop a fundamental understanding of the basic chemical mechanisms of plasmas formed above water surface and to establish a quantitative correlation between gas-phase plasma chemistry and plasma-induced liquid-phase chemistry. To achieve these objectives, the project investigates degradation of a colored industry effluent, Rhodamine B dye, by a dielectric barrier discharge non-equilibrium plasma jet at atmospheric pressure. The experimental approach uses novel radical scavenging and detection techniques, plasma spectroscopy, as well as deuterated and isotopically labeled compounds to identify and quantify plasma radicals and elucidate chemical reactions responsible for the dye degradation.