Characteristics of non-thermal low-frequency Ar–N₂ plasma and its application in microbial decontamination

Abstract Traditional methods to generate non-thermal Ar–N 2 plasma at low pressure conditions have predominantly utilized radiofrequency and direct current power supplies. These techniques have proven efficiency in various applications, including surface modification and microbial decontamination. However, high operational costs and the complex equipment have provoked interest in alternative approaches. This study investigates the characteristics and efficacy of Ar–N 2 plasma generated under vacuum conditions using a low-frequency alternating current power supply at 6 and 9 kHz. The plasma was produced in a capacitively coupled system, with key parameters such as electron density, electron temperature, and the electron energy distribution function (EEDF) were assessed using a single Langmuir probe. Results indicate that the increased driving frequency from 6 to 9 kHz led to a decrease in electron temperature, and electron density at higher pressure, when nitrogen was introduced into the argon plasma. EEDF is shifted from a bi-Maxwellian to a Maxwellian-like shape with increased frequency at fixed power and gas pressure. Additionally, a significant degradation of Xanthomonas campestris pv . vesicatoria from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>6</mml:mn> </mml:msup> </mml:mrow> </mml:mrow> </mml:math> to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>4</mml:mn> </mml:msup> </mml:mrow> <mml:mrow> <mml:mtext> CFU</mml:mtext> </mml:mrow> <mml:mstyle scriptlevel="0"/> <mml:mrow> <mml:mtext>m</mml:mtext> </mml:mrow> <mml:mrow> <mml:msup> <mml:mrow> <mml:mtext>l</mml:mtext> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:mrow> </mml:math> was observed following the antimicrobial treatment, suggesting its potential applications in agriculture, material processing, and sterilization.