Atmospheric pressure argon surface discharges propagated in long tubes: physical characterization and application to bio-decontamination

作者：Kovalova Zuzana; Leroy Magali; Jacobs Carolyn; Kirkpatrick Michael J; Machala Zdenko; Lopes Filipa; Laux Christophe O; DuBow Michael S; Odic Emmanuel

来源：Journal of Physics D: Applied Physics , 2015, 48(46): 464003.

DOI：10.1088/0022-3727/48/46/464003

• bio-decontamination
• low-temperature plasma
• Escherichia coli DH-1
• atmospheric pressure argon pulsed corona discharge
• UV emission
• long dielectric tube

Pulsed corona discharges propagated in argon (or in argon with added water vapor) at atmospheric pressure on the interior surface of a 49 cm long quartz tube were investigated for the application of surface bio-decontamination. H2O molecule dissociation in the argon plasma generated reactive species (i.e. OH in ground and excited states) and UV emission, which both directly affected bacterial cells. In order to facilitate the evaluation of the contribution of UV radiation, a DNA damage repair defective bacterial strain, Escherichia coli DH-1, was used. Discharge characteristics, including propagation velocity and plasma temperature, were measured. Up to similar to 5.5 and similar to 5 log(10) reductions were observed for E. coli DH-1 bacteria (from 106 initial load) exposed 2 cm and 44 cm away from the charged electrode, respectively, for a 20 min plasma treatment. The factors contributing to the observed bactericidal effect include desiccation, reactive oxygen species (OH) plus H2O2 accumulation in the liquid phase, and UV-B (and possibly VUV) emission in dry argon. The steady state temperature measured on the quartz tube wall did not exceeded 29 degrees C; the contribution of heating, along with that of H2O2 accumulation, was estimated to be low. The effect of UV-B emission alone or in combination with the other stress factors of the plasma process was examined for different operating conditions.

• 出版日期2015-11-25
• 单位中国地震局