7th Asia-Pacific Conference on Plasma Physics, 12-17 Nov, 2023 at Port Messe Nagoya

Non-equilibrium cold plasma technologies for health and agricultural
applications

Ram Prakash1, Ramavtar Jangra1, Kiran Ahlawat1, Shikha Pandey1 and Abhijit Mishra1
1
Department of Physics, Indian Institute of Technology Jodhpur, Indiae-mail (speaker): ramprakash@iitj.ac.in
Dielectric Barrier Discharge (DBD) plasmas, sometimes
referred to as atmospheric pressure non-equilibrium cold
plasmas, have recently discovered a wide range of cuttingedge applications in biology, medicine, food, agriculture,etc. Such plasmas effectively destroy spores and biofilms,
which are highly challenging to inactivate, as well asbacteria, yeasts, moulds, and other potentially harmful
microbes including possible bioterrorism agents. Such
plasmas can be used to sterilise and remove biologicalcontaminants from surfaces, water, air, food, and evenliving tissues without endangering them or having anyother unintended consequences [1, and references therein].
Several synergistic mechanisms, including electric fields,
charged particles, UV rays, produced radicals, andreactive species, can be implicated in such plasma
treatments. However, plasma-induced processes are still
frequently viewed as an effective "black-box",
necessitating a deeper comprehension of thesemechanisms, as well as their functions andinterrelationships.
A Cold Plasma Group has been created at IIT Jodhpur,
which is working on non-equilibrium cold plasmas
interventions for health and agriculture applications. Veryrecently, we have come up with a Cold-plasma Detergentin Environment (CODE) device [2], a surface-DBD based
plasma activated water [3], a narrow band 222 nm
Excimer UV lamp, and a new geometry cold atmosphericpressure (CAP) plasma jet. These plasma devices are
made for particular usages related to quality indoor air, forselective generation of Nitrite and Nitrate for better
agriculture yield, for efficiently inactivating drug-resistantbacteria without apparent harm to exposed mammalianskin, and possible use in Endodontics, respectively.
The CODE device effectiveness to deactivate aerosolizedbacteria and viruses has been investigated in indoor spaces
up to 10 x 8 x 8 ft3 in size. In 90 minutes of continuous
operation of the device at the optimized parameters, thetotal microbial counts (TMCs) and total fungal counts(TFCs) are decreased to more than 99%. In 30 minutes
and 90 minutes of device operation in a contained space,
the MS2 phage virus and E. coli bacteria were completely
inactivated with more than 5 log reductions (99.999%).
Fig. 1 depicts the device's schematic view.

Fig.1 Schematic view of the DBD based Cold-plasma
detergent in environment device

The issues addressed are as follows: Enhanced quasineutral electric atmosphere, generated hydroxyl radicals
without UV, nil ozone and/or nil nascent oxygen, achievedsustenance time of negative ions ~25 sec, dimensionallyextendable source, environment friendly.
A low-pressure narrow band 222 nm Far UV-C excimer
lamp has also been designed and developed. Generally, at
low pressure, a very wide band of spectra having FWHM
of 8-15 nm is obtained. The confined gas gap and powersource have been optimized and generated a very narrow
band spectrum from the excimer source having a FWHMof 1.7 nm. The electrical to optical conversion efficiency
as high as 12.5% is obtained. Complete deactivation of
two types of microorganisms, i.e., gram-positive (S.
aureus) and gram-negative (E. coli) occurs at the UV doseof 3 mJ/cm2 and 12 mJ/cm2, respectively.

Fig.2. Developed narrow band 222 nm Far UV-C
excimer lamp
A surface dielectric barrier discharge-based cold plasma
source is also developed with the selective generation ofNitrate and Nitrite in the Plasma Activated Water (PAW).
It is inferred that the PAW is enriched with Nitrate andNitrite, once hydrogen peroxide is nil in the activatedwater. This type of PAW can be highly useful for
agricultural applications. A new geometry CAP helium
plasma jet as shown in Fig. 3 has also been designed anddeveloped for endodontics application.

Fig. 3.A new designed CAP Helium Plasma Jet
In this talk a review of these efforts will be presented andstrategies will be discussed for the multidisciplinary
approach to bring out the real fruits of this emerging areaof research.
References[1]. Ram Prakash, Afaque M Hossain, UN Pal, N Kumar,K Khairnar, M Krishna Mohan, Scientific Reports |7:17426 | (2017).
[2]. Ramavtar Jangra, Kiran Ahlawat, Ambesh Dixit andRam Prakash, Scientific Reports, |13:10295| (2023).
[3]. Shikha Pandey, Ramavtar Jangra, Kiran Ahlawat,
Ritesh Mishra, Abhijit Mishra, Sushma Jangra and Ram
Prakash, Phys Lett. A 474 (2023) 128832.