農水食分野での高電圧・プラズマ利用

Takaki, Koichi; Takahashi, Katsuyuki

doi:10.7791/jspmee.9.108

Cited by 1 publication

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References 16 publications

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“…In recent years, interest in plasma activated water (PAW) has been growing, due to its potential applications in biomedical, food, and agricultural sciences, as well as associated technologies [1][2][3][4][5][6][7][8][9]. PAW is known to be composed of various kinds of reactive transient and long-lived species, and kinetic reactions for their production, conversion and losses have been investigated [10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Comparative study of discharge schemes for production rates and ratios of reactive oxygen and nitrogen species in plasma activated water

Tachibana¹,

Nakamura²

2019

J. Phys. D: Appl. Phys.

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Plasma activated water (PAW) containing reactive oxygen and nitrogen species (RONS) is of great interest for applications in the agricultural and food industries, where processing methods with large capacities and high energy-yields are required. In this work, we studied the differences between seven types of discharge schemes in terms of the production rates and concentration ratios of RONS using deionized water and tap water in comparison. We used N 2 and air as the feed gas with a variable admixture of water vapour. When O 2 was incorporated into the reaction system, the major products in the PAW became NO − 2 and NO − 3 , while small amounts of H 2 O 2 and NH + 4 were detected only in O 2 poor situations with water vapour. Of the major products, the condition of whether NO − 2 or NO − 3 becomes predominant is dependent on the extent of successive oxidation reactions from NO to NO 2 and NO 3 and the competing rates between gas phase reactions and dissolutions into water. In our tested discharge schemes, those with volumetric glow-like discharge structures produced NO − 3 rich PAW, while those with spark discharge structures over the water surface or in water were favourable for the production of NO − 2 rich PAW. In particular, a discharge scheme with a wire-in-nozzle structure operated in a spark-mode with a bubbling gas flow yielded PAW with the highest NO − 2 concentration, more than 70%, at a high energy-yield of 2 g kWh −1 . In the storage period, NO − 2 was converted into NO − 3 due to ionic reactions in aqueous solution, but the buffer action of tap water was observed to suppress the conversion for a fairly long period.Keywords: plasma activated water, reactive oxygen and nitrogen species, NO − 2 , NO − 3 , H 2 O 2 , NH + 4 , energy-yield

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