Microbubble-enhanced DBD plasma reactor: Design, characterisation and modelling

Wright, Alexander R.P.; Taglioli, Matteo; Montazersadgh, Faraz; Shaw, Alexander H.; Iza, Felipe; Bandulasena, Hemaka C.H.

doi:10.1016/j.cherd.2019.01.030

Cited by 43 publications

(20 citation statements)

References 56 publications

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“…Previous studies have demonstrated the effective chemical reaction rates from underwater plasma bubbles translating to remarkably enhanced chemical and biochemical activity for water purification, biomass conversion or biofilm reduction, owing to the high specific interfacial area, high inner pressure and relatively long residence times of plasma bubbles 29 , 49 , 50 . Wright et al modelled the bubbly flow, interfacial mass transfer, transport of species and chemical reactions in the microbubble-DBD reactor and they suggested that the enhanced mass transfer caused a rapid increase and higher final concentrations of reactive species in the liquid phase for the same input conditions to the reactor 51 . The smaller bubble size also influenced the mixing of the liquid, and the fluid velocities induced by the airlift-loop configuration were found to be one order of magnitude larger for smaller bubbles than for larger bubbles 51 .…”

Section: Multiphase Dischargesmentioning

confidence: 99%

Interactions of plasma-activated water with biofilms: inactivation, dispersal effects and mechanisms of action

Mai‐Prochnow

Zhou

Zhang

et al. 2021

npj Biofilms Microbiomes

142

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Biofilms have several characteristics that ensure their survival in a range of adverse environmental conditions, including high cell numbers, close cell proximity to allow easy genetic exchange (e.g., for resistance genes), cell communication and protection through the production of an exopolysaccharide matrix. Together, these characteristics make it difficult to kill undesirable biofilms, despite the many studies aimed at improving the removal of biofilms. An elimination method that is safe, easy to deliver in physically complex environments and not prone to microbial resistance is highly desired. Cold atmospheric plasma, a lightning-like state generated from air or other gases with a high voltage can be used to make plasma-activated water (PAW) that contains many active species and radicals that have antimicrobial activity. Recent studies have shown the potential for PAW to be used for biofilm elimination without causing the bacteria to develop significant resistance. However, the precise mode of action is still the subject of debate. This review discusses the formation of PAW generated species and their impacts on biofilms. A focus is placed on the diffusion of reactive species into biofilms, the formation of gradients and the resulting interaction with the biofilm matrix and specific biofilm components. Such an understanding will provide significant benefits for tackling the ubiquitous problem of biofilm contamination in food, water and medical areas.

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Section: Multiphase Dischargesmentioning

confidence: 99%

Interactions of plasma-activated water with biofilms: inactivation, dispersal effects and mechanisms of action

Mai‐Prochnow

Zhou

Zhang

et al. 2021

npj Biofilms Microbiomes

142

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“…Despite the fact that the highest ozone concentration was achieved with 60% duty cycle (Figure 3), it emerged that the optimum mixture of reactive species for bacterial inactivation was achieved at a 45% duty cycle during the 30-minute operation. The biocidal effects of ROS and RNS have been well established and their production rate depends on the duty cycle used and conditions within the plasma module [19,26]. For a 45% duty cycle, the disinfection level exceeded 5log reductions after a 30-minute treatment time demonstrating the effectiveness of this approach.…”

Section: Reactor Performancementioning

confidence: 99%

“…This is made possible by using a microporous nickel membrane as the sparger as well as the ground electrode (Figure 1(b)). The detailed design and characterization of the reactor have been described in a previous study [14,19], and therefore only a brief description is provided here. The formation of microbubbles in the vicinity of the plasma discharge.…”

Section: Microbubble-gas Plasma Reactor Configurationmentioning

confidence: 99%

“…The air-lift loop reactor technology implemented for low-cost mixing has been reported in the literature for pilot scale bioreactors (~250 L) demonstrating its potential for scale-up [20]. In addition, it would be possible to integrate fluidic oscillator mediated energy efficient microbubble generation technology to this reactor to enhance the mass transfer of reactive species [19]. Rehman et al demonstrated the advantages of using energy-efficient microbubbles in the treatment of wastewater on the basis of improved mass transfer coefficients, mixing efficiency and energy efficiency [31] and this technology has been tested at pilot scale waste water treatment plants.…”

Section: Effect Of Humic Acid On Inactivation Of E Colimentioning

confidence: 99%

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Effect of humic acid on E. coli disinfection in a microbubble-gas plasma reactor

Wright

Uprety

Shaw

et al. 2019

Journal of Water Process Engineering

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Final effluent from wastewater treatment plants may contain bacteria that can pose a range of environmental and health threats. A microbubble-gas plasma reactor capable of producing a number of both reactive oxygen species and reactive nitrogen species has been developed for inactivating bacteria in final effluents. At the optimum operating conditions, greater than 5-log reductions in E. coli viability was achieved in pure water after 30 minutes of operation with an energy consumption of 68 kJ/L. Addition of humic acid reduced the E. coli inactivation rate. At the highest concentration of humic acid tested (0.0015% w/w), E. coli inactivation was reduced by ~50% compared to that achieved in pure water for a 30-minute treatment time. Longer treatment times may be required for waste streams having a high organic content, but the disinfection levels achieved with a low power consumption demonstrate the potential of this approach for industrial use.

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“…The gas exits the reactor through a port in the centre of the top lid. Further details of the reactor used can be found elsewhere [32].…”

Section: Introductionmentioning

confidence: 99%

Influence of the On-time on the Ozone Production in Pulsed Dielectric Barrier Discharges

Montazersadgh

Wright

Ren

et al. 2019

Plasma

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Understanding the production mechanisms of ozone and other reactive species in atmospheric pressure dielectric barrier discharges (DBDs) has become increasingly important for the optimization and commercial success of these plasma devices in emerging applications, such as plasma medicine, plasma agriculture, and plasma catalysis. In many of these applications, input power modulation is exploited as a means to maintain a low gas temperature. Although the chemical pathways leading to ozone production/destruction and their strong temperature dependence are relatively well understood, the effect of the on-time duration on the performance of these modulated DBDs remains largely unexplored. In this study, we use electrical and optical diagnostics, as well as computational methods, to assess the performance of a modulated DBD device. The well-established Lissajous method for measuring the power delivered to the discharge is not suitable for modulated DBDs because the transients generated at the beginning of each pulse become increasingly important in short on-time modulated plasmas. It is shown that for the same input power and modulation duty-cycle, shorter on-time pulses result in significantly enhanced ozone production, despite their operation at slightly higher temperatures. The key underpinning mechanism that causes this counter-intuitive observation is the more efficient net generation rate of ozone during the plasma on-time due to the lower accumulation of NO2 in the discharge volume.

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Microbubble-enhanced DBD plasma reactor: Design, characterisation and modelling

Cited by 43 publications

References 56 publications

Interactions of plasma-activated water with biofilms: inactivation, dispersal effects and mechanisms of action

Interactions of plasma-activated water with biofilms: inactivation, dispersal effects and mechanisms of action

Effect of humic acid on E. coli disinfection in a microbubble-gas plasma reactor

Influence of the On-time on the Ozone Production in Pulsed Dielectric Barrier Discharges

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