Comparative study of discharge schemes for production rates and ratios of reactive oxygen and nitrogen species in plasma activated water
Comparative study of discharge schemes for production rates and ratios of reactive oxygen and nitrogen species in plasma activated water
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DOI：
10.1088/1361-6463/ab2529
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发表时间：
2019-05
期刊：
影响因子：
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通讯作者：
K. Tachibana;Toshihiro Nakamura
中科院分区：
文献类型：
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作者：
K. Tachibana;Toshihiro Nakamura
含有活性氧和活性氮（RONS）的等离子体活化水（PAW）在农业和食品工业中的应用引起了人们的极大兴趣，因为这些工业需要大容量和高能量产率的加工方法。在这项工作中，我们比较了使用去离子水和自来水的七种排放方案在 RONS 产率和浓度比方面的差异。我们使用氮气和空气作为原料气，并混合有不同的水蒸气。当O2进入反应体系时，PAW中的主要产物变成了 和 ，而少量的H2O2 和 仅在O2贫乏且有水蒸气的情况下才检测到。在主要产物中，是否占主导地位的条件取决于从NO到NO2和NO3的连续氧化反应的程度以及气相反应和溶解到水中之间的竞争速率。在我们测试的放电方案中，那些具有体积辉光放电结构的放电方案产生了丰富的PAW，而那些在水面或水中具有火花放电结构的放电方案则有利于产生丰富的PAW。特别是，采用线状喷嘴结构的放电方案，以火花模式和鼓泡气流运行，产生的 PAW 浓度最高，超过 70%，能量产量高达 2 g kWh−1。在储存期间，由于水溶液中的离子反应而转化为，但观察到自来水的缓冲作用在相当长的时间内抑制了转化。
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 N2 and air as the feed gas with a variable admixture of water vapour. When O2 was incorporated into the reaction system, the major products in the PAW became and , while small amounts of H2O2 and were detected only in O2 poor situations with water vapour. Of the major products, the condition of whether or becomes predominant is dependent on the extent of successive oxidation reactions from NO to NO2 and NO3 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 rich PAW, while those with spark discharge structures over the water surface or in water were favourable for the production of 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 concentration, more than 70%, at a high energy-yield of 2 g kWh−1. In the storage period, was converted into 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.