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Inactivation of Bacteria in an Aqueous Environment by a Direct‐Current, Cold‐Atmospheric‐Pressure Air Plasma Microjet
Author(s) -
Liu Fuxiang,
Sun Peng,
Bai Na,
Tian Ye,
Zhou Haixia,
Wei Shicheng,
Zhou Yanheng,
Zhang Jue,
Zhu Weidong,
Becker Kurt,
Fang Jing
Publication year - 2010
Publication title -
plasma processes and polymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 74
eISSN - 1612-8869
pISSN - 1612-8850
DOI - 10.1002/ppap.200900070
Subject(s) - oxidizing agent , atmospheric pressure , plasma , atmospheric pressure plasma , chemistry , direct current , aqueous solution , current (fluid) , staphylococcus aureus , membrane , analytical chemistry (journal) , chromatography , environmental chemistry , bacteria , biochemistry , organic chemistry , thermodynamics , oceanography , physics , quantum mechanics , geology , power (physics) , genetics , biology
A direct‐current, cold‐atmospheric‐pressure air plasma microjet (PMJ) sustained in a quasi‐steady gas cavity in a liquid medium is used to inactivate Staphylococcus aureus ( S. aureus ) suspended in the liquid. The temperature and the pH value of the liquid change to steady‐state values of about 40 °C and 3.0–4.5, respectively, after 10 min of plasma treatment. The decrease in the pH is attributed to the reaction of NO x produced in the air plasma with water at the gas–liquid interface. The concentrations of NO 3 −and NO 2 −are measured to be 37 mg · L −1 and 21 mg · L −1 , respectively, after a 20 min of plasma treatment. Effective inactivation of S. aureus is found to start after the pH values decreases to about 4.5. This is attributed to the high oxidizing potential of the perhydroxyl radical (HOO • ) on the fatty acid in the cell membranes of the microorganisms in the liquid.