Discharge Characteristics of Ar+EtOH Cold Plasma Jet under Nanosecond Pulse Excitation
Xia Wenjie1,2,3,4, Wu Jinxin1,2,3,4, He Bin1,2,3,4, Guo Zikai1,2,3,4, Wang Zhiyuan1,2,3,4
1. State Key Laboratory of Smart Power Distribution Equipment and System Hebei University of Technology Tianjin 300130 China; 2. School of Electrical Engineering Hebei University of Technology Tianjin 300130 China; 3. Hebei Key Laboratory of Bioelectromagnetics and Neural Engineering Tianjin 300130 China; 4. Tianjin Key Laboratory of Bioelectricity and Intelligent Health Tianjin 300130 China
Abstract：Atmospheric pressure cold plasma jet does not require vacuum equipment, is small in size, low in cost and easy and safe to operate. It can generate a variety of active species to react physicochemically and chemically with the surface of the treated material, and has been widely used in the fields of materials science, biomedicine and environmental engineering. Although He plasma jet has excellent performance but is expensive, and the alternative Ar plasma is easy to form unstable filamentary discharge, and the discharge temperature is high with the risk of burns. Scholars at home and abroad have proposed a variety of ways to realize the diffuse discharge of Ar plasma at atmospheric pressure, such as the use of pulsed power supply, reducing the air gap between the electrodes and doping a small amount of easily ionizable gases. In this paper, a small amount of ionizable gas ethanol is doped into Ar to transform the Ar plasma jet into a stable, dispersive plasma jet with low breakdown voltage and close to room temperature, and the effects of different parameters of the driving power supply, the size of the ethanol doping concentration, and the external environment on the discharge characteristics of the Ar+EtOH plasma jet are investigated under nanosecond pulse excitation. Firstly, two plasma jet source structures-with and without quartz shielding-were designed. Secondly, the Ar+EtOH atmospheric pressure cold plasma jet discharge and detection platform are built. Finally, the effects of different discharge parameters and ethanol doping concentration on the characteristics of Ar+EtOH plasma jets were systematically investigated by discharge image analysis, voltage-current characterization, and emission spectral analysis. The plasma diagnosis revealed that the diffusion discharge could not be realized with either too high (> 0.99%) or too low (<0.02%) ethanol doping concentration, and the lower limit of the ethanol doping concentration gradually increased from 0.02% to 0.08% with the increase of the applied voltage from 4 kV to 9 kV, whereas the upper limit of the ethanol doping concentration firstly increased to 0.99% at 6 kV, and then decreased to 0.73%. the dispersive discharge interval was expanded after shielding from ambient air effects. The increase in both voltage and frequency enhanced the discharge intensity of the plasma jet. As the voltage was increased from 4 kV to 9 kV, the discharge current amplitude was increased from 20 mA to 311 mA, the current onset time was increased from 340 ns to 102 ns, and the intensity of the Ar* (763 nm) emission line was increased from 0.087×104(au) to 5.66×104(au). When the frequency was increased from 1 kHz to 25 kHz, and the current amplitude was kept at about 108 mA, the current onset time was increased from 292 ns increased to 88 ns, and the Ar* emission intensity increased from 0.27×104(au) to 5.64×104(au). Low ethanol doping concentration (0.06%~0.28%) increased the discharge current amplitude from 85 mA to 116 mA and advanced the onset time from 240 ns to 108 ns, which may be due to Penning ionization between the ethanol molecule and the substable Ar*. However, excess ethanol doping significantly reduced the OH and Ar* concentrations, suggesting that the ethanol molecules consumed the substable Ar*. The following conclusions can be drawn from the experimental analysis: (1) The appropriate ethanol doping concentration is the key to realize the dispersive discharge of the argon plasma jet, and its optimal range is related to the applied voltage. (2) Shielding the ambient air increases the diffuse discharge interval by eliminating the electronegative oxygen effect. (3) Increases in both voltage and frequency increase the discharge intensity of the Ar+EtOH plasma jet, but frequency does not affect the amplitude of the discharge current, only the onset moment of the discharge current. (4) Low ethanol doping promotes plasma discharge through Penning ionization, while overdoping depletes the active component and reduces the discharge intensity of the jet.
[1] Lu Xinpei, Liu Dawei, Xian Yubin, et al.Cold atmospheric-pressure air plasma jet: physics and opportunities[J]. Physics of Plasmas, 2021, 28(10): 100501. [2] 宋鹏, 李政楷, 陈雷, 等. 大气压低温氦等离子体射流的诊断研究[J]. 光谱学与光谱分析, 2021, 41(6): 1874-1879. Song Peng, Li Zhengkai, Chen Lei, et al.Diagnosis of atmospheric pressure helium cryogenic plasma jet[J]. Spectroscopy and Spectral Analysis, 2021, 41(6): 1874-1879. [3] 张传升, 章程, 任成燕, 等. 聚丙烯基薄膜储能的影响机制及优化策略研究进展[J]. 电工技术学报, 2024, 39(7): 2193-2213. Zhang Chuansheng, Zhang Cheng, Ren Chengyan, et al.Research progress on influence mechanisms and optimization strategies for energy storage in poly- propylene-based films[J]. Transactions of China Electrotechnical Society, 2024, 39(7): 2193-2213. [4] Jiao Jianqiang, Xia Wenjie, Wu Jinxin, et al.Effect of oxygen on the discharge characteristics of argon doped ethanol plasma jet and its application in surface modification of polyimide films[J]. Plasma Sources Science and Technology, 2024, 33(9): 095002. [5] 李陈莹, 陈杰, 刘洋, 等. 基于等离子体射流的电力系统用硅橡胶绝缘材料憎水性提升装置研发[J]. 高压电器, 2020, 56(12): 257-263. Li Chenying, Chen Jie, Liu Yang, et al.Hydro- phobicity enhancement device developed for power equipment silicon rubber insulation materials using in power pystem based on plasma jet[J]. High Voltage Apparatus, 2020, 56(12): 257-263. [6] 张浩, 张基珅, 许德晖, 等. 等离子体活化水溶液用于癌症治疗的研究综述[J]. 电工技术学报, 2023, 38(增刊1): 231-246. Zhang Hao, Zhang Jishen, Xu Dehui, et al.Advances of plasma-activated solutions for cancer therapy[J]. Transactions of China Electrotechnical Society, 2023, 38(S1): 231-246. [7] 刘定新, 张基珅, 王子丰, 等. 等离子体活化介质技术及其生物医学应用[J]. 电工技术学报, 2024, 39(12): 3855-3868. Liu Dingxin, Zhang Jishen, Wang Zifeng, et al.Plasma-activated media technology and its biomedical applications[J]. Transactions of China Electrotech- nical Society, 2024, 39(12): 3855-3868. [8] 夏文杰, 刘定新. Ar等离子体射流处理乙醇水溶液的放电特性及灭菌效应[J]. 电工技术学报, 2021, 36(4): 765-776. Xia Wenjie, Liu Dingxin.Discharge characteristics and bactericidal effect of Ar plasma jet treating ethanol aqueous solution[J]. Transactions of China Electrotechnical Society, 2021, 36(4): 765-776. [9] 李天宇, 孙静, 高钰婷, 等. 等离子体催化及其在电力多元转换的应用研究进展[J]. 电工技术学报, 2024, 39(17): 5461-5481. Li Tianyu, Sun Jing, Gao Yuting, et al.Research progress on plasma catalysis and its applications in power-to-X[J]. Transactions of China Electrotechnical Society, 2024, 39(17): 5461-5481. [10] Naz M Y, Shukrullah S, Rehman S U, et al.Optical characterization of non-thermal plasma jet energy carriers for effective catalytic processing of industrial wastewaters[J]. Scientific Reports, 2021, 11: 2896. [11] Rashid M M, Chowdhury M, Talukder M R.Textile wastewater treatment by underwater parallel-multi-tube air discharge plasma jet[J]. Journal of Environmental Chemical Engineering, 2020, 8(6): 104504. [12] 丁蕴函, 王晓龙, 谭震宇, 等. 大气压He/O2等离子体活性粒子在水溶液中传质的氧含量效应[J]. 电工技术学报, 2023, 38(11): 2977-2988. Ding Yunhan, Wang Xiaolong, Tan Zhenyu, et al.Oxygen concentration effect on the mass transfer of reactive species of the atmospheric-pressure He/O2 plasma in aqueous solution[J]. Transactions of China Electrotechnical Society, 2023, 38(11): 2977-2988. [13] Liu Tiejian, Zeng Yuxuan, Xue Xin, et al.He-plasma jet generation and its application for E. coli steriliza- tion[J]. Journal of Spectroscopy, 2021, 2021: 6671531. [14] 陈慧敏, 段戈辉, 梅丹华, 等. 气体添加对水电极同轴介质阻挡放电直接分解CO2的影响[J]. 电工技术学报, 2023, 38(1): 270-280. Chen Huimin, Duan Gehui, Mei Danhua, et al.Effect of gas addition on CO2 decomposition in a coaxial dielectric barrier discharge reactor with water electrode[J]. Transactions of China Electrotechnical Society, 2023, 38(1): 270-280. [15] Adhikari B C, Lamichhane P, Lim J S, et al.Generation of reactive species by naturally sucked air in the Ar plasma jet[J]. Results in Physics, 2021, 30: 104863. [16] Shao Xianjun, Jiang Nan, Zhang Guanjun, et al.Comparative study on the atmospheric pressure plasma jets of helium and argon[J]. Applied Physics Letters, 2012, 101(25): 253509. [17] Gazeli K, Svarnas P, Held B, et al.Possibility of controlling the chemical pattern of He and Ar “guided streamers” by means of N2 or O2 additives[J]. Journal of Applied Physics, 2015, 117(9): 093302. [18] Walsh J L, Kong M G.Room-temperature atmospheric argon plasma jet sustained with sub- microsecond high-voltage pulses[J]. Applied Physics Letters, 2007, 91(22): 221502. [19] Balcon N, Aanesland A, Boswell R.Pulsed RF discharges, glow and filamentary mode at atmos- pheric pressure in argon[J]. Plasma Sources Science Technology, 2007, 16(2): 217-225. [20] Laimer J, Störi H.Recent advances in the research on non-equilibrium atmospheric pressure plasma jets[J]. Plasma Processes and Polymers, 2007, 4(3): 266-274. [21] Sun Wenting, Li Guo, Li Heping, et al.Characteristics of atmospheric-pressure, radio-frequency glow dischar- ges operated with argon added ethanol[J]. Journal of Applied Physics, 2007, 101(12): 123302. [22] Chang Zhengshi, Jiang Nan, Zhang Guanjun, et al.Influence of Penning effect on the plasma features in a non-equilibrium atmospheric pressure plasma jet[J]. Journal of Applied Physics, 2014, 115(10): 103301. [23] Xia Wenjie, Liu Dingxin, Xu Han, et al.The effect of ethanol gas impurity on the discharge mode and discharge products of argon plasma jet at atmospheric pressure[J]. Plasma Sources Science and Technology, 2018, 27(5): 055001. [24] Xia Wenjie, Liu Dingxin, Guo Li, et al.Discharge characteristics and bactericidal mechanism of Ar plasma jet with ethanol and oxygen gas admixtures[J]. Plasma Sources Science and Technology, 2019, 28(12): 125005. [25] 刘志杰, 陈旻, 刘定新. 大气压冷等离子体的理化特性检测方法综述[J]. 高电压技术, 2022, 48(10): 4196-4214. Liu Zhijie, Chen Min, Liu Dingxin.Review of detection methods for physicochemical characteristics of atmospheric pressure cold plasma[J]. High Voltage Engineering, 2022, 48(10): 4196-4214. [26] 邝勇, 章程, 胡修翠, 等. 纳秒脉冲液相放电耦合微气泡固氮影响因素分析[J]. 电工技术学报, 2023, 38(15): 3960-3971. Kuang Yong, Zhang Cheng, Hu Xiucui, et al.Factors influencing nitrogen fixation by microbubbles coupled with nanosecond-pulse liquid phase discharges[J]. Transactions of China Electrotechnical Society, 2023, 38(15): 3960-3971. [27] 易善婷, 刘峰, 方志. 大气压Ar/NH3/H2O等离子体射流放电特性[J]. 高电压技术, 2019, 45(6): 1936-1944. Yi Shanting, Liu Feng, Fang Zhi.Discharge charac- teristics of Ar/NH3/H2O plasma jet under atmospheric pressure[J]. High Voltage Engineering, 2019, 45(6): 1936-1944. [28] 田思理, 王瑞雪, 章程, 等. 氦等离子体射流子弹及活性粒子时空分布特征研究[J]. 中国电机工程学报, 2018, 38(1): 330-336, 371. Tian Sili, Wang Ruixue, Zhang Cheng, et al.Temporal and spatial study of plasma bullet and reactive species in a helium plasma jet[J]. Proceedings of the CSEE, 2018, 38(1): 330-336, 371. [29] 田富超, 陈雷, 裴欢, 等. 针环式电极大气压下氩气等离子体射流长度影响因素研究[J]. 光谱学与光谱分析, 2023, 43(12): 3682-3689. Tian Fuchao, Chen Lei, Pei Huan, et al.Study of factors influencing the length of argon plasma jets at atmospheric pressure with needle ring electrodes[J]. Spectroscopy and Spectral Analysis, 2023, 43(12): 3682-3689. [30] 杨静茹, 方志, 钱晨. 氩氧大气压等离子体射流放电特性的研究[J]. 真空科学与技术学报, 2014, 34(5): 454-460. Yang Jingru, Fang Zhi, Qian Chen.Discharge characteristics of atmospheric pressure argon/oxygen plasma jet[J]. Chinese Journal of Vacuum Science and Technology, 2014, 34(5): 454-460. [31] Rong Mingzhe, Xia Wenjie, Wang Xiaohua, et al.The mechanism of plasma plume termination for pulse- excited plasmas in a quartz tube[J]. Applied Physics Letters, 2017, 111(7): 074104. [32] Butcher D J.Review: recent advances in optical analytical atomic spectrometry[J]. Applied Spectro- scopy Reviews, 2013, 48(4): 261-328. [33] Xu Han, Liu Dingxin, Liu Zhijie, et al.Contrasting characteristics of gas-liquid reactive species induced by pulse-modulated RF and kHz sinusoidal plasma jets[J]. IEEE Transactions on Plasma Science, 2019, 47(2): 1336-1344. [34] Li Yao, Yang Dezheng, Qiao Junjie, et al.The dynamic evolution and interaction with dielectric material of the discharge in packed bed reactor[J]. Plasma Sources Science and Technology, 2020, 29(5): 055004. [35] Du Changming, Mo Jianmin, Li Hongxia.Renewable hydrogen production by alcohols reforming using plasma and plasma-catalytic technologies: challenges and opportunities[J]. Chemical Reviews, 2015, 115(3): 1503-1542. [36] Bundaleska N, Tsyganov D, Saavedra R, et al.Hydrogen production from methanol reforming in microwave “tornado” -type plasma[J]. International Journal of Hydrogen Energy, 2013, 38(22): 9145-9157. [37] Adámková B, Krčma F, Chudják S, et al.Pinhole discharge decomposition of ethanol[J]. Journal of Applied Physics, 2021, 129(14): 143304. [38] Zare M, Saleheen M, Mamun O, et al.Aqueous-phase effects on ethanol decomposition over Ru-based catalysts[J]. Catalysis Science & Technology, 2021, 11(20): 6695-6707. [39] Kumar A.Ethanol decomposition and dehydrogena- tion for hydrogen production: a review of hetero- geneous catalysts[J]. Industrial & Engineering Chemistry Research, 2021, 60(46): 16561-16576.
2025, Vol. 40 
