Use of Non-Thermal Atmospheric Pressure Plasma for Air Cleaning and Sterilization

Summary form only given. Drexel Plasma Institute has several plasma systems for air cleaning and sterilization. High-volume pulsed corona discharge system has been developed as a core of the mobile pilot plant to demonstrate promising technology for treatment of high volume low concentration (HVLC) industrial ventilation streams contaminated by volatile organic compounds (VOC). Gas phase organic compounds can be destroyed by oxidation to carbon dioxide and water. The effective way of oxidizing organics is to use highly reactive species, i.e. reactants with a high oxidizing potential, such as -OH, -O, -H, O₃, and H₂O₂. The hydroxyl radical is especially known to play an important role in oxidative purification and degradation of organic compounds. In non-thermal plasma, radicals, ions and other active species, which oxidize, reduce or decompose the pollutant molecules, are efficiently produced mainly via electron-impact dissociation, excitation and ionization of the background gas. For the compounds of interest in this project (methanol, acetone, dimethyl sulfide and alpha-pinene), high removal efficiencies were obtained with power levels competitive with the present technologies for the VOCs removal. The pilot plant can treat up to 350 m³/h of air. Experiments with the pilot plant were made with average plasma power up to 3.5 kW. Different designs of the laboratory and pilot plant pulsed coronas, as well as different analytical methods revealed many new peculiarities of the VOC abatement process. The experimental results for the removal efficiency will be presented with respect to energy consumption, residence time, water effect and initial concentration. In addition, generation of organic by-products which are hardly removable by plasma will be discussed. Non-thermal plasma of dielectric barrier discharge (DBD) and gliding arc (GA) is being used as an innovative method to sterilize indoor air in the event of a chemical o- biological terrorist attack. We have constructed a special pathogen detection and remediation facility (PDRF) for handling and processing bacterial and viral bio-aerosols and begun physiochemical modeling to understand and predict plasma´s decontamination effectiveness under the most extreme biological attack scenarios imaginable. PDRF was designed for operation with multiple changeable plasma devices, and two of them - DBD and magnetically rotated GA are put in operation already. Physiochemical modeling of plasma sterilization from airborne microorganisms is a relatively new concept and can provide us with a better understanding of destruction mechanisms of various microorganisms allowing a more efficient plasma reactor design