Atmospheric plasma generates oxygen atoms as oxidizing species in aqueous solutions
Atmospheric plasma generates oxygen atoms as oxidizing species in aqueous solutions
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DOI：
10.1088/0022-3727/49/40/404002
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发表时间：
2016-10-12
影响因子：
3.4
通讯作者：
Benedikt, Jan
中科院分区：
文献类型：
--
作者：
Hefny, Mohamed Mokhtar;Pattyn, Cedric;Benedikt, Jan
一个远程微尺度大气压等离子体射流（mu APPJ）与他，他/H2O，他/O-2，和他/O-2/H2O气体混合物被用来研究运输的活性物种从气相到液体和以下的水相化学。以苯酚为化学探针，通过测定H2 O2浓度和pH值，对μ APPJ在水中引起的影响进行了定量研究。这些结果与反应物种的绝对密度的分析和对流/扩散运输和重组反应的等离子体射流的流出物中的建模相结合。此外，修改后的等离子体射流被用来表明，发射的光子在水化学的作用是可以忽略不计的这些等离子体源。最快的苯酚降解测得的He/O-2等离子体，其次是He/H2O，He/O-2/H2O，和He等离子体。在He/O-2等离子体情况下，O原子进入液体的建模定量通量与苯酚降解速率高度可比，并且显示出反应性物种从等离子体进入液体的非常高的转移效率，其中超过一半的离开喷嘴的O原子进入液体。结果表明，He/O-2等离子体的高氧化效应主要是由于O原子的溶剂化，而OH自由基在等离子体与其他气体混合物在水中诱导的氧化效应中占主导地位。这些发现有助于以定量的方式了解冷大气等离子体与水溶液的复杂相互作用，并将使人们更好地了解这些等离子体与水或含有生物大分子、微生物甚至真核细胞的缓冲溶液的相互作用。此外，mu APPJ He/O-2等离子体源似乎是一个理想的工具，用于在水溶液中生成O原子，用于将来研究其反应性。
A remote microscale atmospheric pressure plasma jet (mu APPJ) with He, He/H2O, He/O-2, and He/O-2/H2O gas mixtures was used to study the transport of reactive species from the gas phase into the liquid and the following aqueous phase chemistry. The effects induced by the mu APPJ in water were quantitatively studied using phenol as a chemical probe and by measuring H2O2 concentration and pH values. These results were combined with the analysis of the absolute densities of the reactive species and the modeling of convective/diffusion transport and recombination reactions in the effluent of the plasma jet. Additionally, modified plasma jets were used to show that the role of emitted photons in aqueous chemistry is negligible for these plasma sources. The fastest phenol degradation was measured for the He/O-2 plasma, followed by He/H2O, He/O-2/H2O, and He plasmas. The modeled quantitative flux of O atoms into the liquid in the He/O-2 plasma case was highly comparable with the phenol degradation rate and showed a very high transfer efficiency of reactive species from the plasma into the liquid, where more than half of the O atoms leaving the jet nozzle entered the liquid. The results indicate that the high oxidative effect of He/O-2 plasma was primarily due to solvated O atoms, whereas OH radicals dominated the oxidative effects induced in water by plasmas with other gas mixtures. These findings help to understand, in a quantitative way, the complex interaction of cold atmospheric plasmas with aqueous solutions and will allow a better understanding of the interaction of these plasmas with water or buffered solutions containing biological macromolecules, microorganisms, or even eukaryotic cells. Additionally, the mu APPJ He/O-2 plasma source seems to be an ideal tool for the generation of O atoms in aqueous solutions for any future studies of their reactivity.