Mode transition of air surface micro-discharge and its effect on the water activation and antibacterial activity
Mode transition of air surface micro-discharge and its effect on the water activation and antibacterial activity
复制标题
空气表面微放电模式转变及其对水活化和抗菌活性的影响
DOI：
10.1088/1361-6595/aba7ef
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发表时间：
2020
影响因子：
3.8
通讯作者：
Dingxin Liu
中科院分区：
文献类型：
--
作者：
Wang Xi;Wei Wang;Zhijie Liu;Zifeng Wang;Li Guo;Xiaohua Wang;Mingzhe Rong;Dingxin Liu
大气压介质阻挡放电等离子体的化学特性对环境温度、放电功率等因素非常敏感。有两种典型的模式，即臭氧模式和氮氧化物模式。在环境温度为5 °C和50 °C，放电功率保持在6 W左右的条件下，分别产生了臭氧模式和氮氧化物模式的空气表面微放电等离子体，并将等离子体废气通入去离子水中制备等离子体活化水（PAW）。通过比较两种模式下等离子体波中的活性物种及其杀菌效果，发现氮氧化物模式下等离子体波中H+、H2 O2、NO2-、NO3-和ONOO-的浓度约为臭氧模式下的2-3倍，而臭氧模式下等离子体波中O3的浓度约为氮氧化物模式下的28倍以上。氮氧化物模式下的杀菌效果比臭氧模式下高两个数量级。对于生物学效应，发现PAW处理耐甲氧西林金黄色葡萄球菌悬液导致氮氧化物模式下约4个对数的减少，这高于臭氧模式，导致推测PAW中以ONOO−为代表的活性氮物种可能是灭菌的关键物种。此外，通过调节放电功率可以实现臭氧模式和氮氧化物模式之间的转换。有趣的是，在5 °C & 9.5W和50 °C & 6 W两种条件下，气相和液相中活性物种的组成和浓度基本相同，表明环境温度对模式转变的影响与放电功率的影响一致。
The chemical characteristics of atmospheric pressure dielectric barrier discharge plasma generated in air are very sensitive to some factors, such as environment temperature and discharge power. There are two typical modes, namely the ozone mode and nitrogen oxides mode. In this paper, the air surface micro-discharge plasma in the ozone mode and nitrogen oxides mode are respectively generated at environment temperatures of 5 °C and 50 °C when discharge power is almost kept at 6 W, and the plasma-activated water (PAW) is prepared by means of passing the plasma exhaust gases into deionized water. By comparing the reactive species in PAW under these two modes and their sterilization effects, it is found that the concentrations of H+, H2O2, NO2 −, NO3 − and ONOO− in PAW for the nitrogen oxides mode are about 2–3 fold over those for the ozone mode, while the concentration of O3 in PAW for the ozone mode is more than 28 times that in the nitrogen oxides mode. The sterilization effect under the nitrogen oxides mode is two orders of magnitude higher than that in the ozone mode. For the biological effects, it is found that treatment of a methicillin-resistant Staphylococcus aureus suspension by PAW leads to approximately a four-log reduction in the nitrogen oxides mode, which is higher than that in the ozone mode, leading to speculations that the reactive nitrogen species represented by ONOO− in PAW may be the critical species in sterilization. Furthermore, the transition between ozone mode and nitrogen oxides mode can be achieved by adjusting the discharge power. Interestingly, both of the compositions and concentrations of the reactive species in gas and liquid phases under 5 °C & 9.5 W and 50 °C & 6 W conditions are roughly identical, indicating that the effect of environment temperature on the mode transition is consistent with that of discharge power.