Plasma for air and water sterilization (original) (raw)
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Air and Water Sterilization using Non-Thermal Plasma
2007 IEEE Pulsed Power Plasma Science Conference, 2007
The sterilization effect of plasma on air and water were investigated in this study * . For air sterilization, a small scale model of HVAC was designed and Dielectric Barrier Discharge plasma source was used for treatment of air. This PDRF (Pathogen Detection and Remediation Facility) consisted of a circulatory airflow system, a plasma chamber and a sampling system. Air sterilization experiments were performed and the inactivation of Escherichia coli was studied. Conventional water sterilization methods such as chlorination, ozonation, filtration, UV irradiation etc have several drawbacks. Pulsed plasma discharge for the destruction of microorganisms in waste water and potable water is a cost effective technique developed recently. The energy efficiency of different types of plasma discharges in water contaminated with Escherichia coli has been studied. The effect of initial concentration of bacterial solution on the inactivation efficiency has also been studied 1-4244-0914-4/07/$25.00 ©2007 IEEE.
Effect of Dielectric and Liquid on Plasma Sterilization Using Dielectric Barrier Discharge Plasma
PLoS ONE, 2013
Plasma sterilization offers a faster, less toxic and versatile alternative to conventional sterilization methods. Using a relatively small, low temperature, atmospheric, dielectric barrier discharge surface plasma generator, we achieved ≥6 log reduction in concentration of vegetative bacterial and yeast cells within 4 minutes and ≥6 log reduction of Geobacillus stearothermophilus spores within 20 minutes. Plasma sterilization is influenced by a wide variety of factors. Two factors studied in this particular paper are the effect of using different dielectric substrates and the significance of the amount of liquid on the dielectric surface. Of the two dielectric substrates tested (FR4 and semi-ceramic (SC)), it is noted that the FR4 is more efficient in terms of time taken for complete inactivation. FR4 is more efficient at generating plasma as shown by the intensity of spectral peaks, amount of ozone generated, the power used and the speed of killing vegetative cells. The surface tem...
Sterilization using dielectric barrier discharge at atmospheric pressure
Fourtieth IAS Annual Meeting. Conference Record of the 2005 Industry Applications Conference, 2005., 2005
A newly developed plasma method has advantages of low temperature operation, time-saving and non-toxicity over the conventional methods, such as dry heat, steam autoclave, γ-ray irradiation and ethylene oxide (EtO) gas. Dielectric barrier discharge (DBD) can be exposed to plasma under atmospheric pressure. The effect of sterilization of Bacillus subtilis and Eschelichia coli (E. coli) was investigated using DBD plasma under dry and wet conditions at atmospheric pressure. The results show that the plasma sterilization method is relatively high speed for Bacillus Subtilis spore compared with conventional methods. The wet plasma method showed higher performance compared with the dry method. These results suggest that H 2 O plays an important role in the sterilization using the DBD plasma.
Applied Biochemistry and Biotechnology, 2010
We developed and employed a new geometrical structure of dielectric barrier discharge in atmospheric pressure for bacterial broad spectrum sterilization. We utilized a plasma source having an AC power supply at 50 HZ and 5,400 V (rms value). We prepared suspensions of the Gram-negative bacteria species (Escherichia coli, Pseudomonas aeruginosa) and a Gram-positive of Bacillus cereus with Luria-Bertani broth media up to OD 600 nm =0.25 of McFarland standard. Afterglow of non-thermal atmospheric pressure plasma treated these suspensions. The influence of the atmospheric plasma afterglow on the species was assayed in different time durations 5, 10, and 15 min. The spectroscopic results of this investigation indicated that the survival reduction of the species can reach to 100% for P. aeruginosa in an exposure time of 10 min, E. coli and B. cereus in an exposure time of 15 min.
Inactivation of Bacteria in Flight by Direct Exposure to Nonthermal Plasma
IEEE Transactions on Plasma Science, 2000
Plasma treatment is a promising technology for fast and effective sterilization of surfaces, waterflow, and airflow. The treatment of airflow is an important area of healthcare and biodefense that has recently gained the interest of many scientists. In this paper, we describe a dielectric barrier grating discharge (DBGD) which is used to study the inactivation of airborne Escherichia coli inside a closed air circulation system. Earlier published results indicate approximately 5-log reduction (99.999%) in the concentration of the airborne bacteria after single DBGD exposure of 10-s duration. This paper investigates plasma species influencing the inactivation. The two major factors that are studied are the effect of charged and short-lived species (direct exposure to plasma) and the effect of ozone. It is shown that for a 25% reduction in direct exposure, the inactivation falls from 97% to 29% in a single pass through the grating. The influence of ozone was studied by producing ozone remotely with an ozone generator and injecting the same concentration into the system, as that produced by the DBGD plasma. The results show a 10% reduction in the bacterial load after 10-s exposure to ozone; thus, ozone alone may not be one of the major inactivating factors in the plasma.
Atmospheric pressure plasma jet effects on sterilization of e. coli and s. aureus
2011 Abstracts IEEE International Conference on Plasma Science, 2011
ABSTRACT form only given. In the recent days, since the epidemic spread of diseases, sterilization has become very important. Atmospheric pressure plasma jets which are used locally and effective results for sterilization procedures are popular. In this study, we produced atmospheric pressure plasma jet with helium flow and used for sterilization of Escherichia coli and Staphylococcus aureus. In the experiments, hundred-fold diluted 250 μlt McFarland bacteria were used in eppendorf tubes for plasma treatment. The effects of plasma treatment time (1, 2, 3 second), applied voltage frequency (5-10 kHz) and amplitude (Vpp 15-16 kV) on sterilization were investigated. Plasma current-voltage characteristics and optical emission results were given.
Inactivation of Escherichia coli by atmospheric pressure plasma jet in water
Journal of Water and Health
The main aim of this work is inactivation of Escherichia coli in water using a laboratory-scale radio-frequency atmospheric pressure Argon plasma jet. This bacterium is widely present in the environment, especially in drinking water, and its pathogenic effects are very harmful. For this purpose, an Argon flow rate of 3.5 slm, maximum plasma power of 200 W, and discharge frequency of 13.56 MHz was conducted to generate a uniform plasma plume for water treatment. 150 ml of drinking water contaminated by E. coli was exposed to the radiation of plasma placed about 3 cm within the water, the treatment time varied from 2 to 6 minutes at 100, 150, and 200 W of plasma input power. The temperature of the plume, discharge current and voltage, and electron density were all measured to characterize the plasma. Active species such as excited molecules, ions, and radicals produced in the plasma in water were detected using the optical emission spectroscopy method. The decreasing behavior of live ...
Features of the Sterilization by VUV/UV Irradiation of Low-Pressure Discharge Plasma
NATO Science for Peace and Security Series A: Chemistry and Biology, 2011
The review is devoted to peculiarities of sterilization of items by VUV/UV radiation of the discharge plasma both in case of the items immersed into the discharge plasma ("direct plasma" treatment), and in case of fl owing afterglow plasma ("remote plasma" treatment). The issues of infl uence of such factors as UV irradiation spectrum, substrate temperature on the UV sterilization effi ciency are also considered.
Low pressure plasma discharges for the sterilization and decontamination of surfaces
New Journal of Physics, 2009
The mechanisms of sterilization and decontamination of surfaces are compared in direct and post discharge plasma treatments in two low-pressure reactors, microwave and inductively coupled plasma. It is shown that the removal of various biomolecules, such as proteins, pyrogens or peptides, can be obtained at high rates and low temperatures in the inductively coupled plasma (ICP) by using Ar/O 2 mixtures. Similar efficiency is obtained for bacterial spores. Analysis of the discharge conditions illustrates the role of ion bombardment associated with O radicals, leading to a fast etching of organic matter. By contrast, the conditions obtained in the post discharge lead to much lower etching rates but also to a chemical modification of pyrogens, leading to their deactivation. The advantages of the two processes are discussed for the application to the practical case of decontamination of medical devices and reduction of hospital infections, illustrating the advantages and drawbacks of the two approaches.
Atmospheric-pressure, nonthermal plasma sterilization of microorganisms in liquids and on surfaces
Pure and Applied Chemistry, 2008
Gas discharge plasma inactivation of microorganisms at low (close to ambient) temperature is a promising area of investigation that is attracting widespread interest. This paper describes atmospheric-pressure, nonthermal plasma (NTP) methods for cold sterilization of liquids and thermal sensitive surfaces. These methods are based on the use of direct current (DC) gas discharge plasma sources fed with steady-state high voltage. Parameters characterizing the plasma sources used (plasma-forming gas, gas flow rate, electric power consumed, etc.) are given. The results for plasma sterilization of different microorganisms (vegetative cells, spores, fungi, biofilms) are presented. An empirical mathematical approach is developed for describing NTP inactivation of microorganisms. This approach takes into account not only the destruction of different components of the cells, but their reparation as well.