Aqueous-phase chemistry and bactericidal effects from an air discharge plasma in contact with water: evidence for the formation of peroxynitrite through a pseudo-second-order post-discharge reaction of H2O2 and HNO2
Aqueous-phase chemistry and bactericidal effects from an air discharge plasma in contact with water: evidence for the formation of peroxynitrite through a pseudo-second-order post-discharge reaction of H2O2 and HNO2
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DOI：
10.1088/0963-0252/23/1/015019
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发表时间：
2014-02-01
影响因子：
3.8
通讯作者：
Clupek, M.
中科院分区：
文献类型：
--
作者：
Lukes, P.;Dolezalova, E.;Clupek, M.
测量了气液界面处以及直接在液体中由气体放电等离子体产生的瞬态物质（羟基自由基、二氧化氮自由基、一氧化氮自由基）和长寿命化学产物（臭氧、过氧化氢、硝酸根离子、二氧化氮），测量结果取决于气体氛围（含氮或含氩的20%氧气混合物）以及等离子体处理水的pH值（通过pH值为3.3、6.9或10.1的缓冲液控制）。以苯酚作为化学探针以及大肠杆菌作为研究对象，评估了水相化学以及这些物质对空气中放电等离子体在水中的化学和杀菌效果的具体贡献。除了羟基化产物（邻苯二酚、对苯二酚、1,4 - 苯醌、羟基 - 1,4 - 苯醌）之外，苯酚的硝化和亚硝化产物（4 - 硝基苯酚、2 - 硝基苯酚、4 - 硝基邻苯二酚、4 - 亚硝基苯酚）证明了二氧化氮自由基、一氧化氮自由基和羟基自由基以及一氧化氮正离子在气液界面处由空气等离子体直接产生，以及在过氧亚硝酸盐（ONOOH）介导的等离子体活化水（PAW）中的放电后过程中产生。对等离子体活化水中过氧化氢和亚硝酸根离子放电后演变的动力学研究表明，其与过氧化氢和亚硝酸根离子之间的准二级反应高度吻合。在pH值为3.3的等离子体活化水中，确定了反应NO₂⁻ + H₂O₂ + H⁺ → ONOOH + H₂O的三级速率常数k = 1.1×10³ M⁻² s⁻¹，ONOOH的生成速率在10⁻⁸ - 10⁻⁹ M s⁻¹范围内。研究表明过氧亚硝酸盐化学显著参与了等离子体活化水的抗菌特性。通过苯酚的pH依赖性降解以及顺,顺 - 粘康酸的检测间接证明了等离子体活化水中存在臭氧，但臭氧对空气等离子体灭活细菌的贡献可忽略不计。
The formation of transient species (OH center dot, NO2 center dot, NO radicals) and long-lived chemical products (O-3, H2O2, NO3-, NO2-) produced by a gas discharge plasma at the gas-liquid interface and directly in the liquid was measured in dependence on the gas atmosphere (20% oxygen mixtures with nitrogen or with argon) and pH of plasma-treated water (controlled by buffers at pH 3.3, 6.9 or 10.1). The aqueous-phase chemistry and specific contributions of these species to the chemical and biocidal effects of air discharge plasma in water were evaluated using phenol as a chemical probe and bacteria Escherichia coli. The nitrated and nitrosylated products of phenol (4-nitrophenol, 2-nitrophenol, 4-nitrocatechol, 4-nitrosophenol) in addition to the hydroxylated products (catechol, hydroquinone, 1,4-benzoquinone, hydroxy-1,4-benzoquinone) evidenced formation of NO2 center dot, NO center dot and OH center dot radicals and NO+ ions directly by the air plasma at the gas-liquid interface and through post-discharge processes in plasma-activated water (PAW) mediated by peroxynitrite (ONOOH). Kinetic study of post-discharge evolution of H2O2 and NO2- in PAW has demonstrated excellent fit with the pseudo-second-order reaction between H2O2 and NO2-. The third-order rate constant k = 1.1 x 10(3)M(-2) s(-1) for the reaction NO2- + H2O2 + H+ -> ONOOH + H2O was determined in PAW at pH 3.3 with the rate of ONOOH formation in the range 10(-8)-10(-9) Ms-1. Peroxynitrite chemistry was shown to significantly participate in the antibacterial properties of PAW. Ozone presence in PAW was proved indirectly by pH-dependent degradation of phenol and detection of cis, cis-muconic acid, but contribution of ozone to the inactivation of bacteria by the air plasma was negligible.