코로나방전플라즈마제트장치의 조업특성과 살균력

Abstract

A corona discharge plasma jet (CDPJ) treatment system was fabricated and its operation characteristics were determined. Also the microbial inactivation efficacy of CDPJ was evaluated in order to explore its potentialities as a nonthermal sterilization technology. The system consisted of power supply, transformer, electrode assembly, air blower,and sample treatment plate. Plasma was generated by corona discharge between tungsten lid electrodes with air stream blowing at high speed resulting in downward plasma ejection as a jet. Higher currents and, consequently,greater power were required for the plasma generation as the frequencies increased. Plasmas were generated at a current greater than 1.0 A and frequencies over 32.5 kHz. Stable plasma jets were acquired when the current and the frequency exceeded 1.5 A and 40.0 kHz. Plasma jet length was extended with the current strength. The maximum temperature increased after a 2 min treatment was less than 25oC regardless of the current strength, indicating that the technology belonged to the non-thermal processing category. The CDPJ inactivation effect against Escherichia coli increased with the current strength. More than 4.5 log reduction was achieved by 1 min treatment at 1.5A. The inactivation pattern fitted to a 2-stage 1st order reaction model.