Air Cleaning
Objective 1.1. Investigations of plasma-catalyst interactions
Objective 1.2. Plasma-catalysis for exhaust air treatment
Objective 1.3. Plasma-photocatalysis for indoor air decontamination
EnvADWICE
Environmental Applications of electrical Discharges for Water and aIr Cleaning,
and agriculturE
Project funded by EU NextGenerationEU through the Recovery and Resilience Plan for Slovakia under the project No. 09I03-003-V03-00033 EnvAdwice
Electrical discharges that generate non-thermal (cold) plasmas (NTP) at ambient pressure are widely used in a growing number of applications, and have significant potential within various advanced industrial processes, environmental technologies, sustainable agriculture, and medicine. NTP plasma is considered a powerful tool for initiating reactive chemical processes in gases, liquids, and material surfaces. NTP is a partially ionized gas consisting of electrons, ions, excited and ground state molecules, atoms, and radicals. These applications are based on the cold plasma chemical effects, where particles and radicals generated in the plasma initiate processes in gases and liquids that occur neither in classical conditions, nor in equilibrium (thermal) plasma.
This project centers on the practical application of nonthermal plasma generated by electrical discharges. A primary focus of the project is air cleaning, explored in Work Package 1 (WP1), utilizing plasma both with and without supplementary catalysts. Water treatment and activation represent another crucial aspect, detailed in WP2, also leveraging nonthermal plasma technology. The project investigates the efficacy of different electrical discharge methods for generating the necessary plasma, using advanced optical and electrical diagnostic techniques. WP1 specifically examines the role of catalysts in enhancing plasma's effectiveness for air purification. WP2 delves into the mechanisms by which plasma interacts with and purifies water. A novel application of plasma-activated water is explored in WP3 for agricultural purposes. WP3 will specifically test the effects of plasma-treated water on seed germination and plant growth.
The project aims to bridge the gap between fundamental research on nonthermal plasma and its real-world applications. The findings from WP1, WP2, and WP3 will contribute to the development of sustainable and innovative environmental and agricultural solutions.
Besides scientific work packages, projects also includes WP4 (Administration and management), and WP5 (Dissemination and exploitation). Providing administrative and management support (WP4) for the effective fulfilment of the scientific objectives of the project is essential to meeting the scientific objectives. Within WP5, the project will ensure dissemination in open-access highly reputed scientific journals and at international conferences.
What we do
Water Cleaning
Objective 2.1. Investigations of electrical discharges interacting with water
Objective 2.2. Diagnostics of micropollutants and reactive particles in plasma-activated water
Objective 2.3. Plasma wastewater treatment
Green Agriculture
Objective 3.1. Electrical discharges with water for nitrogen fixation
Objective 3.2. Plant growth promotion by plasma-activated water
Objective 3.3. Towards optimization and scale-up of plasma-activated water systems
Experimental methods (How we do it)
To bring more light into the mutual interaction of electrical discharges and catalytic materials and to induce synergistic effects that can be exploited in environmental applications, we investigate the properties of discharges generated on surfaces, in capillary tubes, cavities, and pellets of materials with catalytic properties, by various electrical and optical diagnostic methods. The understanding of the mechanisms of plasma- catalysts interaction will lead us to testing exhaust gas cleaning and indoor air decontamination from odors, pollutants and pathogenic bio-aerosols.
The complexity of the system where the gas discharge is generated in contact with liquids or catalysts implies high demands on the diagnostic methods to study the electrical discharges, the treated gas, and the plasma activated water (PAW). Monitoring PAW-induced effects on microorganisms and plants requires another set of diagnostic methods. For simplicity, the applied techniques are divided into several groups, described in individual subsections.
Non-thermal plasma
Electrical discharges forming non-thermal plasma will be generated by different types of high voltage power supplies (DC, AC, or pulsed), depending on the specific application. Our lab is equipped with many power supplies (DC; AC; pulsed).
We investigate several configurations of electric discharges in contact with materials of different shapes, composition and catalytic properties (e.g. TiO2, ZrO2, BaTiO3, Pt) and their plasma chemical effects. Namely: 1) Discharges in capillary tubes to mimic automotive catalysts with a similar geometric structure. 2) Discharges in pellets for the elementary studies of plasma-catalyst interaction and chemical processes in plasma catalysis. Besides the laboratory scale plasma-catalytic systems for exhaust air cleaning, we will also test larger devices for indoor cleaning where plasma will be combined with TiO2 photocatalysis, ozonation and UV irradiation.
Diagnostics of plasma discharges
Electrical discharge characteristics will be measured by the high voltage probes and current monitors. The measured signals will be recorded by digital oscilloscopes. These measurements are needed for the calculation of the power input and energy efficiency of the plasma cleaning processes.
Optical emission spectroscopy, both time-integrated and nanosecond time-resolved will be used to investigate the physical characteristics of the studied discharges, both with and without water. We will attempt to determine the temperature of electrons, electron density or the reduced electric field strength. Intermediate reactive species will be identified.
Analysis of gases
We use several diagnostic methods for monitoring the concentrations of gaseous products. UV-Visible absorption spectroscopy will be used for the detection of NO, NO2, O3, and HNO2. Infrared absorption spectroscopy, which is more versatile than UV-Visible spectroscopy, allows us to analyse the plasma treated gases, e.g. HNO3, N2O, CO, CO2 and almost all volatile hydrocarbons can be detected. A Fourier transform infrared (FT-IR) spectrophotometer is be used. High sensitivity can be used when using 5 and 8 m long multi-pass absorption gas cells. To complement the gas analysis, gas chromatography equipped with FID and TCD detectors is used. This gas chromatograph is couples to a new mass spectrometer (MS). Using a combined GC-MS device, precise identification of many unidentified gaseous products is possible.
Analysis of liquids
One of the most efficient ways to activate water with plasma-generated reactive particles is making aerosol microdroplets, either by ultrasonic or mechanical nebulizers or by using high voltage nozzle that generates electrospray. We use several types of fast cameras that enable recording videos with a high frame rate, to visualize the nebulized and electrosprayed water microdroplets and to measure their size. We also employ an optical particle sizer for this need, which allows counting microdroplets and particles with sub-micron sizes and obtain their size distributions.
Plasma-activated water and water solutions are typically acidified and contain various reactive oxygen and nitrogen species delivered from the plasma discharge. We monitor the pH of PAW by calibrated pH meters its conductivity, total dissolved solids and oxidation-reduction potential. The concentrations of nitrites (NO2-), nitrates (NO3-) and hydrogen peroxide (H2O2) and ozone (O3) in PAW are detected by the colorimetric methods (UV/VIS absorption spectrophotometer and microplate-reader ). Fluorescence spectrometry is used for hydroxyl radicals (OH), peroxynitrites (ONOO-) and O3 detection.. We plan to apply calibration-free laser induced breakdown spectroscopy (LIBS) for the analysis of polluted water contaminants, either by drying the sample on pure Si substrate, or by using the droplet levitation technique. We are acquiring new infrastructure for detailed and even more precise and more reliable liquid diagnostics including the organic components and ions, such as high precision liquid chromatography (HPLC) and ion chromatography (IC).
Seeds and plants treatment
One of the key objectives of the project is to achieve improvement in the cultivation of agricultural seeds and enhance the growth on plants by using PAW. PAW is a source of nitrogen exploitable by plants in the form of nitrates, and also contains many reactive oxygen species stimulating various physiological processes, such as e.g. seed germination. We perform seed germination and early seedling growth in controlled laboratory conditions in pots, in hydroponic and aeroponic systems, as well as under outdoor conditions that simulate the field farming. We will monitor the water intake of PAW by the seeds and their imbibition rate. We will determine selected growth parameters (length of roots and shoots, number and quality of leaves, fresh and dry weight of seedlings and plants, key vitality indexes, photosynthesis parameters, antioxidant enzymes and growth factors, etc., in some cases in outdoor conditions even fruit and seed production) to determine an optimal dose and application of PAW. Lignification of the root tissues will be observed by optical and fluorescence microscopy on the lignin deposition on the free hand sections of the roots. The scientific aim is to understand the correlation between the seed germination induction and the quality of plant growth parameters.
Investigating water decontamination effects
Micropollutant water pollution represents a challenge for conventional wastewater treatment technologies. Micropollutants are typically of organic nature, include low concentration pharmaceutical contaminants (e.g. various drugs, hormones, antibiotics), trace pesticides from agriculture, microplastics, as well as associated microbes. Plasma effects on microorganisms in model wastewater on in bio-aerosols or on seed/seedling germination/early growth is tested on model bacteria and yeast. . For microbiological cultivation we will use a sterile box equipped with laboratory glass, balances, pipettes, vortex, autoclave and a thermostat for a controlled microbial growth. Antimicrobial effects are examined by cultivation methods by comparing with fluorescence microscopy visualization and various fluorescence staining methodsin reference and treated water. Chemical low concentration contaminants, their degradation and by-products will be thoroughly analyzed by various sensors, UV-vis absorption spectroscopy, HPLC, and ion chromatography.
Results
In this section we will present our results and outcomes related to/funded by EnvAdwice project.
Journal papers
Janda, M., Stancampiano, A., di Natale, F., Machala, Z., 2025. "Short Review on Plasma–Aerosol Interactions," Plasma Processes and Polymers 22, 2400275.
https://doi.org/10.1002/ppap.202400275
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Conference proceedings
Vazquez T, Lavrikova A, Wiedermann D, Babic J, and Machala Z, Indoor Air Cleaning By Non-Thermal Plasma And Photocatalysis, 25th Symposium on Applications of Plasma Processes (SAPP XXV) & the 14th EU-Japan Joint Symposium on Plasma Processing, Štrbské Pleso, Slovakia, January 31 - February 5, 2025, pp.74-76
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Veis P, Peralta J C, Shetty S J, Veis M, Dhanada V S, Neelmani and Urbina I A, Trace Elements Detection And CF Elemental Analysis Of Water By LIBS For Environmental Control- Comparison Of Surface Assisted, Acoustic Levitation And Ne Methods, 25th Symposium on Applications of Plasma Processes (SAPP XXV) & the 14th EU-Japan Joint Symposium on Plasma Processing, Štrbské Pleso, Slovakia, January 31 - February 5, 2025, p. 78
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Janda M, Polprasarn K, Pareek P, and Pai D: In-Situ Diagnostic Of Electrospray By Raman Light Sheet Microspectroscopy, 25th Symposium on Applications of Plasma Processes (SAPP XXV) & the 14th EU-Japan Joint Symposium on Plasma Processing, Štrbské Pleso, Slovakia, January 31 - February 5, 2025, p. 99-104.
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Kšanová J, Cimerman R, Oberste-Beulmann C, Galmiz O, Švec P, and Hensel K: Cyclic Plasma-Catalytic System Of Catalyst Deactivation And Regeneration Applied For VOC Removal, 25th Symposium on Applications of Plasma Processes (SAPP XXV) & the 14th EU-Japan Joint Symposium on Plasma Processing, Štrbské Pleso, Slovakia, January 31 - February 5, 2025, p. 147-148.
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Kimani B G, Mehrabifard R, Galmiz O, and Machala Z: Investigating The Combined Antiyeast Efficacy Of Plasma-Activated Water And Natural Phenolics On Planktonic Debaryomyces Hansenii, 25th Symposium on Applications of Plasma Processes (SAPP XXV) & the 14th EU-Japan Joint Symposium on Plasma Processing, Štrbské Pleso, Slovakia, January 31 - February 5, 2025, p. 205-208.
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Mišúthová A, Lukačová Z, Ghulam M, Mehrabifard R, Šerá B, and Machala Z, Effect Of Plasma-Activated Water On Physiological Parameters In Bean Plants (Phaseolus Vulgaris), 25th Symposium on Applications of Plasma Processes (SAPP XXV) & the 14th EU-Japan Joint Symposium on Plasma Processing, Štrbské Pleso, Slovakia, January 31 - February 5, 2025, p.215-218
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Tóth P, Janda M, and Smirnov S, Emission Spectra Of Transient Spark With Electrospray, 25th Symposium on Applications of Plasma Processes (SAPP XXV) & the 14th EU-Japan Joint Symposium on Plasma Processing, Štrbské Pleso, Slovakia, January 31 - February 5, 2025, pp.246-250
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Janda M, Tóth P, Smirnov S, Machala Z., Visualization of the transient spark discharge in contact with water supplied through the anode,
16th Frontiers in Low Temperature Plasma Diagnostics, Kerkrade, Netherlands, April 12-16, 2026, p. 62
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Destrieux A, Wiederman D, Babic J, Palko M, Palko M, Machala Z., Large scale air decontamination system using dielectric barrier discharge combined with UV activated TiO2, Central European Symposium on Plasma Chemistry 2025, Bucharest, Romania, September 1-5, 2025, p. x
presentation - 1st slide
Mišúthová A, Lukačová Z, Mehrabifard R, Machala Z, Cultivation of hydroponic Lettuce in PAW: effects on growth, pigmentation, and sensory quality, Plant Biology CS 2025, Bratislava, Slovakia, August 26 - September 28, 2025
Mišúthová A, Mehrabifard R, Lukačová Z, Machala Z, Effect of plasma-activated water on Lactuca sativa L. growth and development in hydroponic cultivation system, 10th Central – European Symposium on Plasma Chemistry : 21st International Conference on Plasma Physics and Applications, Central European Symposium on Plasma Chemistry 2025, Bucharest, Romania, September 1 - September 5, 2025
Mehrabifard R, Mišúthová A, Machala Z, Comparison of three plasma-activated water systems on the growth and germination of Lactuca sativa L. plants, 10th Central – European Symposium on Plasma Chemistry : 21st International Conference on Plasma Physics and Applications, Central European Symposium on Plasma Chemistry 2025, Bucharest, Romania, September 1 - September 5, 2025
Mišúthová A, Mehrabifard R, Ghulam M, Lukačová Z, Šerá B, Machala Z, Plasma-Activated Water Applications for Plant Growth Enhancement: Seed Priming, Hydroponics, and Outdoor Planting, International Workshop on Plasma Agriculture, Philadelphia (USA), Drexel University, June 8 - June 12, 2025
Mišúthová A, Mehrabifard R, Lukačová Z, Machala Z, Dual Role of Plasma-Activated Water in Hydroponic Lettuce: Nitrogen Supplementation and Growth Enhancement via ROS Signaling, 11th International Conference on Plasma Medicine & 10th International Workshop on Plasmas for Cancer Treatment, Gifu, Japan, May 31 - June 5, 2026
Machala Z, Destrieux A, Vazquez T, Lavrikova A, Purification of indoor air by non-thermal DBD plasma combined with photocatalysis, 14th Asian-European International Conference on Plasma Surface Engineering (AEPSE 2025), Phuket, Thailand, November 2-6, 2025, p. x.
Destrieux A, Vazquez T, Lavrikova A, Wiedermann D, Babic J, Machala Z, LARGE SCALE AIR DECONTAMINATION SYSTEM USING DIELECTRIC BARRIER DISCHARGE COMBINED WITH UV ACTIVATED TIO2, The 4th Plasma Nanotechnologies and Bioapplications Workshop, Češkovice, Czech Republic, October 20-23, 2025, p. x
Ahlawat K., Chithran A., Janda M., Machala Z., Plasma under Liquid via Microbubble Discharge: Enhanced Formation of Reactive Oxygen and Nitrogen Species, Central European Symposium on Plasma Chemistry 2025, Bucharest, Romania, September 1-5, 2025, p. 109
Vazquez T., Destrieux A., Lavrikova A., Wiederman D., Babic J., Palko M., Palko M., Janda M., Hensel K., Machala Z., Indoor air decontamination by non-thermal DBD plasma and photocatalysis, 36th International Conference on Phenomena in Ionized Gases, XXXVI ICPIG, Aix-en-Provence (France), July 20-25, 2025, p. 61.
Mehrabifard R, Chithran A, Kimani BG, Machala Z, Stability of reactive species produced in plasma-activated water by various atmospheric air discharges and their antimicrobial potential, International Conference on Phenomena in Ionized Gases 36th Edition (ICPIG 2025), Aix-en-Provence, France, July 20-25, 2025, p. 318
Janda, M., Pareek, P., Tóth, P., Smirnov, S., Generation of plasma activated water with biocidal effects by transient spark combined with electrospray, The 4th Plasma Nanotechnologies and Bioapplications Workshop, Češkovice, ČR, October 20-23, p. 82-83.
Galmiz, O., Kimani, B. G., Machala, Z. Surface activation and biofilm removal on polymeric tubing by atmospheric pressure plasma, Central European Symposium on Plasma Chemistry (CESPC) X, September 1-5, 2025, Bucharest, Romania
Hensel et al., Honeycomb Discharges – Their Physical Properties And Chemical Potential For Environmental Applications, International Plasma Technology Joint Conference 2025 (IPTJC2025), June 25–28, 2025, Ming Chi University of Technology, New Taipei, Taiwan
Machala, Z., Hassan, M. E., Pareek, P., Janda, M., Tuning the plasma-activated water by controlling the transport of reactive species from cold plasma into water bulk and aerosols, 26th International Symposium on Plasma Chemistry ISPC26, Minneapolis, MN, USA, June 15–20, 2025
Galmiz, O., Kimani, B. G., Cimerman, R., Machala, Z., Surface DBD in contact with liquids to produce reactive species in liquids and to decontaminate catheters, 26th International Symposium on Plasma Chemistry ISPC26, Minneapolis, MN, USA, June 15–20, 2025
Mehrabifard R., Kimani B.G., Machala Z., The effect of UVC radiation on plasma activated water on killing Ggram- negative bacteria, Final Meeting PlasTHER COST Action, Barcelona, Spain, June 17-20, 2025, p. x
Cimerman, R., Kšanová, J., Oberste-Beulmann, Ch., Galmiz, O., Švec, P., Hensel, K., Cyclic plasma-catalytic system applied for VOC removal with repetitive deactivation and regeneration of catalysts, 26th International Symposium on Plasma Chemistry ISPC26, Minneapolis, MN, USA, June 15–20, 2025
Machala Z, Hassan M.E., Janda M., Controlling the transport of reactive species from cold plasma into water bulk and aerosols, The 8th European Symposium on Electrohydrodynamic Atomization and Electrospinning 2025, Nicosia, Cyprus, 28 – 30 April, p. 82 (2025).
Janda M., Polprasarn K, Parek P, Pai D., In-situ Diagnostic of electrospray by Raman light sheet microspectroscopy, The 8th European Symposium on Electrohydrodynamic Atomization and Electrospinning 2025, Nicosia, Cyprus, 28 – 30 April, p. 25 (2025).
Janda M, Pareek P, Kimani B.G., Kelar-Tučeková Z, Machala Z., Activation and bio-decontamination of water by cold atmospheric plasma, towards green fertilizer with lower environmental impact, 13 International Conference on Toxic Cyanobacteria (ICTC13), 4-8 May 2025, Chania, Greece, p. 234
Veis P, Peralta J C, Shetty S J, Veis M, Dhanada V S, Neelmani and Urbina I A, Trace Elements Detection And Cf Elemental Analysis Of Water By Libs For Environmental Control- Comparison Of Surface Assisted, Acoustic Levitation And Ne Methods, 25th Symposium on Applications of Plasma Processes (SAPP XXV) & the 14th EU-Japan Joint Symposium on Plasma Processing, Štrbské Pleso, Slovakia, January 31 - February 5, 2025, p. 78
Mehrabifard, R., Chithran, A.,Kimani Gitura, B., Machala, Z., Reactive species stability in plasma-activated water generated by different atmospheric pressure plasmas MatFyz CONNECTIONS 2025, Bratislava, Slovakia, Nov 26, 2025, p.13
Ahlawat, K., Chithran, A., Janda, M., Machala, Z., Rapid Degradation of Coumarin via In Situ Hydroxyl Radical Generation Induced by Recycled Gas from a DBD Plasma Bubble Reactor MatFyz CONNECTIONS 2025, Bratislava, Slovakia, Nov 26, 2025, p.16
Destrieux, A., Lavrikova, A., Vazquez, T., Machala, Z., Large scale air decontamination system using dielectric barrier discharge combined with UV activated TiO2 MatFyz CONNECTIONS 2025, Bratislava, Slovakia, Nov 26, 2025, p.36
Janda, M., Veis, M., Pareek, P., Veis, P., Atikukke, S. Quantification of eroded Fe contamination in plasma activated water using Surface Assisted LIBS MatFyz CONNECTIONS 2025, Bratislava, Slovakia, Nov 26, 2025, p.38
Mišúthová, A., Lukačová, Z., Mehrabifard, R., Machala, Z., Plasma-activated water enhances growth, antioxidant activity and sensory quality of hydroponically grown lettuce MatFyz CONNECTIONS 2025, Bratislava, Slovakia, Nov 26, 2025, p.40
Jangra, R., Selvaraj, G., Hensel, K. Non-Thermal Plasma-Assisted VOC Decomposition: Influence of Catalyst Type, Electron Energy, and Gas Residence Time MatFyz CONNECTIONS 2025, Bratislava, Slovakia, Nov 26, 2025, p.47
Dissemination activities
Kick-off seminar, September 18, 2024
The kick-off internal seminar of the 'EnvADWICE' project was held on 18.9.2024
with the presentation of prof. Machala, who presented the project and its work
packages, objectives, and milestones to all members of the Environmental
Physics division, including all PhD. students, and some Bc. and MSc. students.
The focus was on WP2 - Water cleaning: "Production and Transport of Reactive
Oxygen / Nitrogen Species from Cold Plasma into Liquid Water Bulk /
Aerosols".
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Who we are
Team members
Pavel Veis (R4 level researcher).
Richard Cimerman (R2 level researcher).
Sahithya Atikukke (R2 level researcher).
Adriana Mišúthová (R2 level researcher).
Zlatka Kelar-Tučeková (R2 level researcher).
Ján Čatloš (project administrator).
Katarína Szárazová (laboratory technician).
Michal Amena (technician).
