Effect of Storage Temperature on pH and Conductivity of Reverse Osmosis Water Treated with Atmospheric Plasma

Figueira, Fernanda Ramos; Doria, Anelise C.O.C.; Khouri, Sônia; Maciel, Homero Santiago; Pessoa, Rodrigo Sávio; Ramos, Marco Antonio Ramírez

doi:10.1615/plasmamed.2018028327

Cited by 8 publications

(7 citation statements)

References 8 publications

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“…No change in pH and a significant reduction in ORP of PAW after seven days stored at room temperature was also observed by Joshi et al [35], with a subsequent loss of antibacterial effects. Similarly, plasma activated reverse osmosis water stored at 3 • C or 24 • C did not show any difference in pH values and conductivity after 96 h storage time [36]. The last studies are in agreement with our study that pH was found to be stable during the elongated storage time.…”

Section: Discussionsupporting

confidence: 92%

Temperature Stability and Effectiveness of Plasma-Activated Liquids over an 18 Months Period

Tsoukou

Bourke

Boehm

2020

Water

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Non-buffered plasma-activated liquids such as water and saline have shown bactericidal effects. In the present study, we investigated the anti-bacterial efficacy and stability of plasma-activated water (PAW) and plasma-activated saline (PAS), generated using a high voltage dielectric barrier discharge system. This study compares the potential of non-buffered plasma-activated liquids (PAL) for the inactivation of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) after storage of the solutions at five different temperatures for a storage time up to 18 months after their generation. The temperatures used were room temperature, 4 °C, −16 °C, −80 °C, −150 °C. Both PAW and PAS achieved 6 log reduction for both bacteria on the first day of their generation after 60 min contact time and they retained these effects after 18 months when stored at the lowest temperatures. Chemical analysis of PAL showed that plasma caused a drop in pH, generation of reactive oxygen species and nitrates, whereas no nitrites are detected in the system used. The concentrations of chemical species were affected by the storage at different temperatures and a thermocouple probe was used to investigate the freezing behaviour of the PAL.

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Section: Discussionsupporting

confidence: 92%

Temperature Stability and Effectiveness of Plasma-Activated Liquids over an 18 Months Period

Tsoukou

Bourke

Boehm

2020

Water

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“…ORP is reported to be the principal responsible for destructing microbiological systems' membrane integrity with the fundamental function of affecting the cells' inner and outer membranes [52]. Among the RONS generated in PAW, hydrogen peroxide (H 2 O 2 ) is mainly responsible for the formation of ORP [53] and has a rapid potential for disinfection of liquids [17,54,55].…”

Section: Effect Of Water Dynamic Plasma Activationmentioning

confidence: 99%

“…This plasma water activation technique is inexpensive and environmentally friendly since it is free of chemicals [9]. For this type of application, atmospheric non-thermal plasmas (ANTP) are used, namely, the dielectric barrier discharge (DBD) or the gliding arc plasma jet (GAPJ) [10][11][12][13][14][15][16][17]. The plasma used as a water activating agent can be applied directly submerged in the liquid or applied to millimeters of the liquid's surface [18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

“…Thinking about the construction of a bench device for water activation/treatment, which can be used in gynecological, dental, and medical clinics, it is more advantageous to use plasma applied to millimeters from the surface, which facilitates the architecture of building a device, without lose the effectiveness of inactivation of microbial species [8][9][10][11][12][13][14][15][16][17]. However, despite PAW's tremendous technological appeal, mainly due to its potent antimicrobial effects and wide application in clinical practice, some technical challenges need to be overcome.…”

Section: Introductionmentioning

confidence: 99%

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Antimicrobial Effect of Plasma-Activated Tap Water on Staphylococcus aureus, Escherichia coli, and Candida albicans

Chiappim

Sampaio

Miranda

et al. 2021

Water

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In this study, the potential antimicrobial activity of plasma-activated tap water (PAW) was evaluated against Staphylococcus aureus, Escherichia coli, and Candida albicans. For this, PAW was prepared in a gliding arc plasma system using two treatment conditions: stagnant water and water stirring by a magnetic stirrer, called moving water. Subsequently, their oxidation-reduction potential (ORP), pH, electrical conductivity (σ), and total dissolved solids (TDS) were monitored in different areas of the sample divided according to the depth of the beaker. It was observed that PAW obtained in dynamic conditions showed a more uniform acidity among the evaluated areas with pH 3.53 and ORP of 215 mV. Finally, standardized suspensions of Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 10799), and Candida albicans (SC 5314) were treated with PAW, and the reduction of viable cells determined the antimicrobial effect. Our results indicate that the tap water, activated by plasma treatment using gliding arc, is an excellent inactivation agent in the case of Staphylococcus aureus and Escherichia coli. On the other hand, no significant antimicrobial activity was achieved for Candida albicans.

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“…Many active and reactive biochemical substances and radicals arise in the water during the process of plasma activation [16]. In most cases, especially for distilled water [17], this is associated with a massive decrease in pH and a high increase of the oxidation potential.…”

Section: Introductionmentioning

confidence: 99%

Generation of Plasma-Activated Fluids for Successful Disinfection of Pseudomonas aeruginosa in Liquid Environments and Determination of Microbial Damage

Hummert,

Leenders,

Mellmann

et al. 2023

Plasma

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The application of the non-thermal atmospheric pressure plasma technology is a promising tool for microbial inactivation. During the activation process, many reactive substances and radicals arise associated with physicochemical changes in the fluid and massive pH drop. In this study, we analyzed and optimized plasma activation settings and conditions of water and liquids to obtain inactivation of the waterborne microorganism Pseudomonas aeruginosa in a liquid environment. The minimal electrical output was 60 Watt with 20 min activation time followed by 30 min contact time with 108 cells/mL. Using higher electrical power (>90 W) with a Lab Unit generating plasma-activated water, a shorter activation time (<10 min) was sufficient for bacterial inactivation. The organic and inorganic composition of the activated liquid with different mineral salt concentrations is of utmost importance for the yield of reactive species during the plasma activation process and consequently for the antimicrobial effect. Plasma-activated fluids with high organic and inorganic contents demonstrated lower inactivation efficiencies than low loaded fluids; yet antimicrobial efficacy could be achieved by increasing the electrical power and activation time. For sufficient inactivation of bacterial suspensions, at least half a volume unit of plasma-activated water had to be added after appropriately optimized activation. Further dilutions reduced the antimicrobial effect. PAW lost activity after being left standing for a prolonged time after activation, so for maximizing the antimicrobial effect a direct use after activation is recommendable. Bacterial inactivation was shown by the absence of colony forming units on culture media and, at the molecular level, damage to the membrane and inactivation of enzymes were observed. Plasma-activated fluids demonstrated a high potential in applications as microbiological disinfectant in liquids.

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Effect of Storage Temperature on pH and Conductivity of Reverse Osmosis Water Treated with Atmospheric Plasma

Cited by 8 publications

References 8 publications

Temperature Stability and Effectiveness of Plasma-Activated Liquids over an 18 Months Period

Temperature Stability and Effectiveness of Plasma-Activated Liquids over an 18 Months Period

Antimicrobial Effect of Plasma-Activated Tap Water on Staphylococcus aureus, Escherichia coli, and Candida albicans

Generation of Plasma-Activated Fluids for Successful Disinfection of Pseudomonas aeruginosa in Liquid Environments and Determination of Microbial Damage

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