Efficacy and mechanism of inactivation of bacterial aerosols by non-thermal plasma
JIAO Yang1,2, JI Shuo1,2, YU Xin1,2, WANG He1,2, DANG Xiao-qing1, ZHANG Yu-fei1
1. School of Environment & Municipal Engineering, Xi'an University of Architecture & Technology, Xi'an 710055, China; 2. Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Key Laboratory of Environmental Engineering of Shaanxi Province, Xi'an 710055, China
Abstract：To address the issue of indoor bacterial aerosol transmission and ensure air biosafety, an experiment was conducted utilizing E. coli and Bacillus subtilis. as model strains, with non-thermal plasma employed as a means of sterilization. The study investigated the impact of input voltage, carrier gas flow rate, and initial concentration on the efficiency of bacterial aerosol inactivation. Analysis of OES, EPR, and biological characterization results revealed that reactive species (primarily including 1O2, O2-, ·OH) generated by non-thermal plasma during the inactivation process disrupted the bacteria's cell membrane leading to protein leakage, breakdown of lipids and nucleic acids ultimately resulting in complete bacterial inactivation. Increasing input voltage while decreasing flow rate could improve inactivation efficiency. However, when the initial concentration increased to a threshold, the improvement on the inactivation efficiency was negligible. The resistance of the two bacteria aerosols inactivated by non-thermal plasma was: Bacillus subtilis > E. coli. Specifically, Bacillus subtilis demonstrated an inactivation rate constant (k) of 0.0038L/J along with an energy efficiency value of 0.027 (kW∙h)/m3; whereas for E. coli these values were measured at 0.0043L/J and 0.021 (kW∙h)/m3 respectively indicating that non-thermal plasma was more effective against gram-negative bacteria such as E. coli.
[1] Mannan M, Al-Ghamdi S. Indoor air quality in buildings: A comprehensive review on the factors influencing air pollution in residential and commercial structure [J]. International Journal of Environmental Research and Public Health, 2021,18(6):3276. [2] 全海芹,高彦峰.室内空气污染及净化方法综述[J]. 环境科学与技术, 2022,45(S1):254-262. Quan H, Gao Y. Indoor air pollution and purification methods: A review [J]. Environmental Science & Technology, 2022,45(S1):254- 262. [3] Wang C, Prather K, Sznitman J, et al. Airborne transmission of respiratory viruses [J]. Science, 2021,373(6558):eabd9149. [4] 武艳,荣嘉惠,Luhung I.空调通风系统对室内微生物气溶胶的影响[J]. 科学通报, 2018,63(10):920-930. Wu Y, Rong J, Luhung I. Influence of air conditioning and mechanical ventilation (ACMV) systems on indoor microbial aerosols [J]. Chinese Science Bulletin, 2018,63(10):920-930. [5] Song L, Zhou J, Wang C, et al. Airborne pathogenic microorganisms and air cleaning technology development: A review [J]. Journal of Hazardous Materials, 2022,424(Pt B):127429. [6] Morawska L, Allen J, Bahnfleth W, et al. A paradigm shift to combat indoor respiratory infection [J]. Science, 2021,372:689-691. [7] Berry G, Parsons A, Morgan M, et al. A review of methods to reduce the probability of the airborne spread of COVID-19 in ventilation systems and enclosed spaces [J]. Environmental Research, 2022, 203:111765. [8] Xie Y, Zhu X, Zhang P, et al. Cost-effective instant air disinfection for building ventilation system by a combination of UV and micro-static electricity [J]. Chemical Engineering Journal, 2023,454:140231. [9] Yu X, Li S, Dang X, et al. Facile fabrication of three-dimensional MnO2 for trichloroethylene degradation by plasma catalysis [J]. Separation and Purification Technology, 2023,325,124680. [10] Liang Y, Wu Y, Sun K, et al. Rapid inactivation of biological species in the air using atmospheric pressure nonthermal plasma [J]. Environmental Science & Technology, 2012,46(6):3360-3368. [11] Ito E, Baek K, Jang D, et al. Instant inactivation of aerosolized SARS-CoV-2by dielectric filter discharge [J]. Plos One, 2022,17(5): e0268049. [12] Park J, Baek K, Kim S, et al. Development of high durability plasma filter for air circulating disinfection system [J]. Current Applied Physics, 2022,41:100-110. [13] Li S, Li Y, Yu X, et al. A novel double dielectric barrier discharge reactor for toluene abatement: Role of different discharge zones and reactive species [J]. Journal of Cleaner Production, 2022,368:133073. [14] 黄宇,李荣,崔龙,等.轨道交通列车内空气质量研究现状与展望[J]. 地球环境学报, 2020,11(4):345-363. Huang Y, Li R, Cui L, et al. Air quality standard and pollution of railway transit system [J]. Journal of Earth Environment, 2020,11(4): 345-363. [15] Zhou F, Niu M, Zheng Y, et al. Impact of outdoor air on indoor airborne microbiome under hazy air pollution: A case study in winter Beijing [J]. Journal of Aerosol Science, 2021,156:105798. [16] Li S, Yu X, Dang X, et al. Double dielectric barrier discharge incorporated with CeO2-Co3O4/γ-Al2O3 catalyst for toluene abatement by a sequential adsorption–discharge plasma catalytic process [J]. Journal of Cleaner Production, 2022,340:130774. [17] Matyakubov N, Nguyen D, Saud S, et al. Effective practical removal of acetaldehyde by a sandwich-type plasma-in-honeycomb reactor under surrounding ambient conditions [J]. Journal of Hazardous Materials, 2021,415:125608. [18] Mehta P, Barboun P, Go D, et al. Catalysis enabled by plasma activation of strong chemical bonds: A review [J]. ACS Energy Letters, 2019,4(5):1115-1133. [19] Wang Q, Yu J, Chen X, et al. Non-thermal plasma oxidation of Cu(II)-EDTA and simultaneous Cu(II) elimination by chemical precipitation [J]. Journal of Environmental Management, 2019,248: 109237. [20] Zhang L, Liu Z, Guo Y, et al. Kinetic model of grating-like DBD fed with flowing humid air [J]. Plasma Sources Science and Technology, 2024,33(2):025001. [21] Kim H, Teramoto Y, Negishi N, et al. A multidisciplinary approach to understand the interactions of nonthermal plasma and catalyst: A review [J]. Catalysis Today, 2015,256:13-22. [22] Yin R, Guo W, Wang H, et al. Singlet oxygen dominated peroxydisulfate activation by sludge-derived biochar for sulfamethoxazole degradation through a nonradical oxidation pathway: Performance and mechanism [J]. Chemical Engineering Journal, 2019,357:589-599. [23] He Z, Li Q, Xu Y, et al. Production of extracellular superoxide radical in microorganisms and its environmental implications: A review [J]. Environmental Pollution, 2023,338:122563. [24] Xu H, Zhu Y, Du M, et al. Subcellular mechanism of microbial inactivation during water disinfection by cold atmospheric-pressure plasma [J]. Water Research, 2021,188:116513. [25] Xia D, An T, Li G, et al. Synergistic photocatalytic inactivation mechanisms of bacteria by graphene sheets grafted plasmonic Ag-AgX (X=Cl, Br, I) composite photocatalyst under visible light irradiation [J]. Water Research, 2016,99:149-161. [26] Hernandez-Gordillo A, Arriaga S. Mesoporous TiO2 monoliths impregnated with CdS and CuO nanoparticles for airborne bacteria inactivation under visible light [J]. Catal Letters, 2022,152(3):629- 640. [27] 赵璐瑶,张佳丽,张轲,等.介质阻挡放电协同Ag-Cu/TiO2-CS复合光催化剂灭活生物气溶胶的实验研究[J]. 中国环境科学, 2024,44(5):2777-2785. Zhao L Y, Zhang J L, Zhang K, et al. Experimental study on the inactivation of bioaerosols by dielectric barrier discharge combined with Ag-Cu/TiO2-CS composite photocatalyst [J]. China Environmental Science, 2024,44(5):2777-2785. [28] Wen G, Liang Z, Xu X, et al. Inactivation of fungal spores in water using ozone: Kinetics, influencing factors and mechanisms [J]. Water Research, 2020,185:116218. [29] 蒋励铭,卞静,张晓晖,等.电化学活化过氧乙酸灭活水中大肠杆菌[J]. 中国环境科学, 2023,43(8):3966-3973. Jiang L, Bian J, Zhang X, et al. Inactivation of E. coli in water by electrochemical activation of peracetic acid [J]. China Environmental Science, 2023,43(8):3966-3973. [30] Farmer E E, Mueller M J. ROS-mediated lipid peroxidation and RES- activated signaling [J]. Annual Review of Plant Biology, 2013,64(1): 429-450. [31] Gao Q, Wang Z, Rao Y, et al. Oxygen vacancy mediated alpha-MoO3 bactericidal nanocatalyst in the dark: Surface structure dependent superoxide generation and antibacterial mechanisms [J]. Journal of Hazardous Materials, 2022,443(Pt B):130275. [32] Yin C, Meng F, Chen G. Spectroscopic characterization of extracellular polymeric substances from a mixed culture dominated by ammonia- oxidizing bacteria [J]. Water Research, 2015,68:740-749. [33] Badireddy A, Korpol B, Chellam S, et al. Spectroscopic characterization of extracellular polymeric substances from Escherichia coli and Serratia marcescens: Suppression using sub- inhibitory concentrations of bismuth thiols [J]. Biomacromolecules, 2008,9:3079-3089. [34] Zhang L, Wang H, Luo H. Uncovering the inactivation kinetics of Escherichia coli in saline by atmospheric DBD plasma using ATR FT-IR [J]. Plasma Processes and Polymers, 2020,17(9):1900197. [35] Stadtman E. Protein oxidation and aging [J]. Free Radical Research, 2009,40(12):1250-1258. [36] Luo H, Liang Z, Wang X, et al. Effect of gas flow in dielectric barrier discharge of atmospheric helium [J]. Journal of Physics D: Applied Physics, 2008,41(20):205205. [37] 杨金月,党小庆,李世杰,等.低温等离子体灭活微生物气溶胶的效果及影响因素[J]. 环境工程学报, 2022,16(12):3984-3992. Yang J, Dang X, Li S, et al. Inactivation effect of non-thermal plasma on bioaerosol and its influencing factors [J]. Chinese Journal of Environmental Engineering, 2022,16(12):3984-3992. [38] Ding H, Wang T, Sun Y, et al. Role and mechanism of cold plasma in inactivating alicyclobacillus acidoterrestris in apple juice [J]. Foods, 2023,12(7):1531. [39] Zhang L, Guo Y, Tie J, et al. Grating-like DBD plasma for air disinfection: Dose and dose-response characteristics [J]. Journal of Hazardous Materials, 2023,447:130780. [40] Park C W, Hwang J. Susceptibility constants of airborne bacteria to dielectric barrier discharge for antibacterial performance evaluation [J]. Journal of Hazardous Materials, 2013,244:421-428. [41] Wu Y, Liang Y, Wei K, et al. MS2 virus inactivation by atmospheric- pressure cold plasma using different gas carriers and power levels [J]. Applied and Environmental Microbiology, 2015,81(3):996-1002. [42] 吴戈辉,赵辉,万琪琪,等.紫外灭活水中3种致病性曲霉的效能及其光复活控制[J]. 中国环境科学, 2022,42(3):1173-1181. Wu G, Zhao H, Wan Q, et al. Inhibit the photoreactivation of three pathogenic Aspergillus spores in water by UV: kinetics and mechanism [J]. China Environmental Science, 2022,42(3):1173-1181. [43] 李凡,徐志凯.医学微生物学第9版[M]. 北京:人民卫生出版社, 2018:364. Li F, Xu Z. Medical microbiology ninth edition [M] Beijing: People's Medical Publishing House, 2018:364. [44] Liu L, Laghari A A, Meng G, et al. Photocatalytic disinfection of different airborne microorganisms by TiO2/MXene filler: Inactivation efficiency, energy consumption and self-repair phenomenon [J]. Journal of Environmental Chemical Engineering, 2022,10(3):107641.
