Double jet atmospheric pressure plasma as a decontaminating agent

Abstract

Atmospheric pressure plasmas jet are recently of high interest due to the promising biomedical applications <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1,2</sup> . Double atmospheric pressure plasma jet system was used to disinfect date-palm fruits. The double jet was formed by blowing argon gas though ceramic alumina tube. It has two capillaries of 1 mm inner diameter for each and 31.5 mm outer diameter. The two capillaries are separated by 3.8 mm. The generated double jet plasma was characterized electrically, spectroscopically and photographically. A high voltage ∼20 kHz sinusoidal wave was applied to a copper ring electrode surrounding the tube. The two jets were ignited simultaneously and homogeneous plasma is formed as indicated from the current waveform. Photographic investigation shows that the double plasma jet length increases with the increase in argon gas flow rate to reach optimum length at 3.5 l/min. However, the double jet shrinks with higher flow rates. The presence of OH, O radicles, excited nitrogen molecules and argon species were detected in the double jet spectra, at 3 mm from jet nozzle. The presence of reactive species nominated the double jet to be as sterilized tool. Therefore, the double jet plasma was successfully used to inactivate A. niger spores, inoculated onto sterilized date palm discs at different flow rate from 0.5 to 4.5 l/min. with optimum efficacy measured at 3.5 l/min which is probably related to the higher amount of reactive species, OH and O radicals.