Dielectric Barrier Discharge Research Articles

Comparative transcriptomic insight into orchestrating mode of dielectric barrier discharge cold plasma and lactate in synergistic inactivation and biofilm-suppression of Pichia manshurica

Pichia manshurica is a representative species of biofilm-forming yeasts which usually induces the spoilage of fermented food. This study aims to investigate the synergistic inactivating and anti-biofilm effect of dielectric barrier discharge cold plasma (DBD) and lactate on Pichia manshurica (P. manshurica) and the underlying mechanism by comparison of survival rate, growth curve, biofilm-forming capacity and transcriptome of P. manshurica treated with control (CK), lactate (LA), DBD, and combination of DBD and lactate (DBD-LA). Results showed that CK and LA hardly influenced the growth and biofilm formation of P. manshurica. DBD and DBD-LA reduced survival rate to 35% and 10% immediately after treatment, respectively. Also, with growth curve remaining plateau, DBD-LA completely inhibited the growth and biofilm formation of P. manshurica, while DBD moderately reduced the growth density and biofilm. Comparative transcriptomic analysis revealed that single DBD treatment intervened in the functions and pathways associated with DNA replication and cell adhesion (down-regulated expression of flocculation protein-related genes and up-regulated expression of β-1,4-D-glucan cellobiohydrolase-related genes). Lactate reinforced the inactivating and anti-biofilm effect of DBD by stimulating redox reaction and suppressing functions and pathways involving synthesis and metabolism of lipid and membrane, cation binding and organelle assembly. This study demonstrated the potential of synergistic combination of DBD and lactate in efficient control of biofilm-related spoilage of food by yeast.

Optimizing germination in tomato (Solanum lycopersicum) seeds through non-thermal plasma treatment

Abstract This study explores the efficacy of non-thermal plasma (NTP) treatment in enhancing the germination of tomato (Solanum lycopersicum) seeds. The experimental setup utilized a dielectric barrier discharge (DBD) system with specific parameters, including voltage, frequency, and treatment duration. Optical emission spectroscopy (OES) was employed to characterize the reactive oxygen and nitrogen species (RONS) generated during plasma treatment. Seeds subjected to plasma for durations ranging from 60 to 300 s were assessed for various germination parameters, including germination percentage, mean germination time, and seedling vigor. Our findings demonstrate significant improvements in germination efficiency, particularly evident at 120 and 180 s of exposure, where germination percentages increased by 113.0% and 83.3%, respectively, compared to control (untreated) seeds. Moreover, seeds subjected to NTP showed reduced mean germination times and enhanced synchronization in germination compared to the control group. Optical characterization revealed the presence of reactive species that likely contribute to the improved seed performance. These findings highlight the promise of non-thermal plasma as an eco-friendly method for improving seed germination in agriculture.

Theoretical kinetics with one-dimensional fluid model and experimental investigation on coaxial XeCl excilamps

Abstract This paper presents a one-dimensional homogenous model of high power-density XeCl excilamp pumped by dielectric barrier discharge (DBD) with larger discharge gap and lower Cl2 density in Xe/Cl2 mixture, to research the electrical and chemical discharge characteristics leading to the production of XeCl* molecules for the optimal discharge parameters. The peaked wavelength 308 nm from the emission band of XeCl* exciplex molecules, show great promise as photochemotherapy for biomedicine applications. The temporal evolutions of the plasma voltage, current density and the species densities have been analyzed. The model validity has been checked by comparing with the experimental results. It is shown that the XeCl excilamp is a capacitive discharge during the entire voltage cycle and the accumulation of charge deposited in the dielectric surfaces play an extreme role in promoting the extinction of this discharge and the generation of next discharge. The UV radiant efficiency of the DBD XeCl excilamp depends on effect of the discharge behavior on the amplitude of the applied voltage, the total gas pressure, and the Cl2 density. XeCl excilamp has an optimized pressure around 150 mbar with the maximum radiant efficiency of 8.5% for 308 nm from XeCl* molecules and 1.3% for 172 nm from Xe2* molecules. According to the corrected simulation, the radiant efficiency of the optimum pressure is 6.0% for XeCl*molecules. Cl2 density in DBD-based XeCl excilamp strongly influence the balance of electron production and loss due to the dominant dissociative attachment process of electrons to Cl2 molecules, which have significant dependence on the UV light output efficiency. It is demonstrated that the highest XeCl* density occurs near the dielectric during the current pulse. Therefore, electrical and radiant characteristics of XeCl excilamps can be considered as the basis to design the high power-density exciplex lamps in practical applications.

Sublethal injury and recovery of Escherichia coli O157:H7 after dielectric barrier discharge plasma treatment.

Dielectric barrier discharge (DBD) plasma can be used to control food spoilage and food pathogens. However, DBD plasma may induce sublethal injury in microorganisms, constituting a considerable risk to food safety. This research was designed to investigate the sublethal injury and recovery of Escherichia coli O157:H7 after DBD plasma treatment. The results indicated that the sublethal injury ratios of cells rose along with the augmentation of treatment time and input power of DBD plasma under mild treatment conditions, whereas injury accumulation ultimately culminated in cell death. The highest sublethal ratio of 99.3% was obtained after DBD plasma treatment at 18W for 40s. When solutions such as phosphate buffered saline (PBS), peptone water, glucose solution, and tryptic soy broth (TSB) were used for cell recovery, TSB was proven to be the most efficacious, facilitating the completion of recovery within 2h. The repair ratio of injured cells increased as the recovery pH (3.0-7.0) and temperature (4-37 ºC) increased. Moreover, Mg2+ and Zn2+ were demonstrated to be necessary for the recovery process, while Ca2+ presented a weak effect. Understanding the sublethal injury of bacteria resulting from DBD plasma treatment and their repair conditions can provide useful insight into avoiding the occurrence of sublethal injury as well as inhibiting the occurrence of recovery during food processing and storage.

Study on the parameters of non-thermal plasma degradation process based on the combination of simulation and experiment

The destruction of benzene in a dielectric barrier discharge (DBD) reactor was studied in this work. The effects of specific energy density, initial concentration and oxygen content on benzene degradation efficiency were investigated by experiment and matrix correlation analysis. The results showed that specific energy density was the most important factor on benzene removal with a Pearson's coefficient of 0.7, meanwhile both initial concentration and oxygen content presented the inverse influence. In addition, a model to study the plasma discharge process was developed by COMSOL simulation software and surface reactions were included in the model. The behavior of the plasma was described by the coupled equations of electron density, heavy matter density and electron mean energy, and the drift-diffusion equation was calculated. When the peak voltage is 30 kV, the terminal current obtained by the simulation is 0.03 A, and the corresponding output current measured by the experiment is 0.013 A. Simulated and experimental current change trends are the same, indicating that the method simulation is correct and reasonable.

Polymerization of Sodium 4-Styrenesulfonate Inside Filter Paper via Dielectric Barrier Discharge Plasma

This work explores the polymerization of sodium 4-styrenesulfonate (NaSS) inside filter paper using dielectric barrier discharge (DBD) plasma and its application in the environmental field. The plasma-based technique, performed under mild conditions, solves common problems associated with conventional polymerization inside porous materials. The polymerization process was monitored using Fourier-transform infrared (FTIR) spectroscopy, which confirmed the consumption of double bonds, particularly in NaSS samples containing the optimal concentration of crosslinker divinyl benzene (DVB) (0.25% wt). Our work demonstrates the effectiveness and promise of DBD plasma as a substitute polymerization approach, especially for those in porous materials.

Development of pilot-scale plasma bubble reactors for efficient antibiotics removal in wastewater

Plasma bubble (PB) is a promising technology to control antibiotic wastewater pollution. However, the practical implementation of PB technology at the industrial-scale is still underdeveloped. In addition, the influence of different discharge modes for PB on wastewater treatment is largely unknown. This study designed pilot-scale PB reactors with different discharge modes to investigate the degradation effect of norfloxacin (NOR) and tetracycline (TC) in bulk tap water. Results indicate that the dielectric barrier discharge (DBD) mode with low average discharge power demonstrates superior degradation ability and higher production of O3(g) and .O2−(aq) compared to the spark mode which exhibits the high-intensity spark discharge in the tip area of the tube. After 40 min of treatment in a Double DBD reactor, 97.4% and 100% of NOR and TC are removed from 2 L tap water, attributed to the accumulation of antibiotic molecules by PBs and the in-situ generation of O3(g) and .O2−(aq) produced by plasma. Furthermore, a larger-scale PB reactor is developed by creating an array of four DBD reactors, effectively degrading 8 L mixed antibiotics solution. This study provides valuable insights for PB reactor design and the degradation performance of antibiotic wastewater, which will contribute to the further development of synergistic systems for plasma degradation.

DBD plasma induced SMOSI and encapsulation for regulation of Brønsted-Lewis acid sites of Cr-MOFs@ZrO2

Dielectric barrier discharge (DBD) plasma for the synthesis of Zr-MOFs followed by the calcination and combination with Cr-MOFs was presented to prepare a Brønsted-Lewis bifunctional catalyst for the conversion of glucose to 5-hydroxymethylfurfural (HMF). The strong electric field on the catalyst surface formed by DBD plasma induced the enhancement of strong metal oxide support interaction (SMOSI), which could be indicated by XPS. SMOSI could change the embedding degree of metal micro-particles. SMOSI accompanied with the encapsulation of Zr metal nanoparticles could regulate the acid sites of the catalysts. Lewis acid played an important role in the isomerization of glucose to fructose, while Brønsted acid played a key role in the further conversion of glucose. The strong Brønsted acid sites determined the conversion of glucose to HMF. Cr-MOFs@ZrO2-D with the DBD plasma method afforded a higher Brønsted to Lewis acid ratio, compared with Cr-MOFs@ZrO2-S with the hydrothermal method. Glucose conversion of 97.9 % and HMF yield of 38 % were obtained with DMF solvent system and Cr-MOFs@ZrO2-D at 150 °C for 2h. This research provided a new method for preparing Zr-MOFs by DBD plasma and a new idea to comprehensively understand the role of Brønsted and Lewis acid sites in glucose conversion.

Streamer propagation dynamics in a nanosecondpulsed surface dielectric barrier discharge in He/N2mixtures

Streamer propagation dynamics in a nanosecondpulsed surface dielectric barrier discharge in He/N2mixtures

Plasma‐Activated Hydrogel Synergies With Paclitaxel to Enhance the Anticancer Efficacy

ABSTRACTCold atmospheric plasma‐activated hydrogel (PAH) exhibits excellent loading and slow‐release capacity for plasma‐generated reactive species. In this study, plasma‐activated pluronic F127 hydrogel (PAH‐PF127) was obtained using surface dielectric barrier discharge (SDBD), and the anticancer effects of PAH‐F127 synergies with the clinical drug paclitaxel (PTX) were investigated. The results indicated that PAH‐PF127 could load plasma‐generated long‐lived reactive species efficiently, and in vitro research revealed that PAH‐PF127 exerts significant anticancer effects by inducing intracellular oxidative stress, and synergies with 50 μg/mL (low‐dose) PTX could easily replace 200 μg/mL (high‐dose) PTX alone. These results suggested that PAH‐PF127 has the potential to address the toxic side effects of high‐dose drugs and expand the application of plasma technology in anticancer treatment.

Physico-chemical and biological characterization of urban municipal landfill leachate and treatment by ozone process

Thewaste production nationwide is increasing every year, on account of therapid urbanization and growing populations, also consumption modes. Algerian political authorities have chosen Technical Landfill Centres (TLC) as a competitive and safe technique of waste management.However, storing these wastes in a bad way poses several environmental challenges, especially in the Department of Saïda, the latter have significant groundwaters. The major problem registered on this Landfill is the leachate resulting from the degradation of buried wastes which were disposed off the outside of the leachate basinand present a source of pollution for the local groundwaters by heavy metals and pathogenic germs.The present paper investigates the leachate treatment ozone process produced by Dielectric Barrier Discharge (DBD) under high potential.The experimental resultsobtained allowed us to show the efficiency of the treatment process by ozone based on the micro pollutant analysis (COD, BOD5 , TOC, heavy metals) and microbial analysis, after ozonation treatment.The results show that 80% of micro pollutants are eliminated and 100% destruction of all bacteria which reveals the high efficiency of the process.

Ion Chemistry in Dielectric Barrier Discharge Ionization: Recent Advances in Direct Gas Phase Analyses.

Dielectric barrier discharge ionization (DBDI) sources, employing low-temperature plasma, have emerged as sensitive and efficient ionization tools with various atmospheric pressure ionization processes. In this review, we summarize a historical overview of the development of DBDI, highlighting key principles of gas-phase ion chemistry and the mechanisms underlying the ionization processes within the DBDI source. These processes start with the formation of reagent ions or metastable atoms from the discharge gas, which depends on the nature of the gas (helium, nitrogen, air) and on the presence of water vapor or other compounds or dopants. The processes of ionizing the analyte molecules are summarized, including Penning ionization, electron transfer, proton transfer and ligand switching from secondary hydrated hydronium ions. Presently, the DBDI-MS methods face a challenge in the accurate quantification of gaseous analytes, limiting its broader application in biological, environmental, and medical realms where relative quantification using standards is inherently complex for gaseous matrices. Finally, we propose future avenues of research to enhance the analytical capabilities of DBDI-MS.

Essentials and Pertinence of Cold Plasma in Essential Oils, Metal–Organic Frameworks and Agriculture

ABSTRACTCold atmospheric pressure plasma (CAPP) comprises an ensemble of ionized gas, neutral particles, and/or reactive species. Electricity is frequently used to produce CAPP via a variety of techniques, including plasma jets, corona discharges, dielectric barrier discharges, and glow discharges. The type and flow rates of the carrier gas(es), temperature, pressure, and vacuum can all be altered to control the desired properties of the CAPP. Since a few decades ago, CAPP has become a widely used technology with applications in every walk of life. The plasma activated liquid mediums like water, ethanol, and methanol have been merged as novel sterilizers. With recent advancements in material science, particularly work on metal–organic frameworks (MOFs), essential oils, and agricultural technologies, CAPP has become a vital component of these advancements. Likewise, CAPP has been found as a green and benign technology to induce early seed germination and plant development. This review covers the critical components of CAPP, the production of reactive oxygen and nitrogen species, and mechanisms by which CAPP‐based technologies are applied to agricultural products, MOFs, and essential oils.

Degradation of sulfamethoxazole in a falling film dielectric barrier discharge system: Performance, mechanism and toxicity evaluation

The ubiquitous presence of sulfonamides (SAs) in wastewater poses serious risks to human health and ecosystem safety. This study evaluated the performance of a falling film dielectric barrier discharge (DBD) system on the removal of five SAs, namely sulfamethoxazole (SMX), sulfisoxazole (SIZ), sulfathiazole (STZ), sulfadiazine (SDZ) and sulfamerazine (SMR). Removal efficiencies >99 % were observed for all target SAs within 30 min of treatment, with pseudo-first order rate constants varying between 0.17 and 0.27 min−1. Superior removal efficiencies were achieved under acidic conditions compared to neutral and alkaline conditions. Using SMX as a model compound, mechanistic investigations revealed that the synergy of reactive oxygen species (ROS) and reactive nitrogen species (RNS) led to its efficient degradation, with peroxynitrites (ONOO−/ONOOH) and hydroxyl radical (OH) playing pivotal roles. SMX degradation pathways encompassing nitration/nitrosation, hydroxylation, deamination, CS and SN bond cleavage were proposed. The toxicity evaluation results demonstrated that the solution toxicity diminished following the plasma treatment under specific conditions. In particular, the solution treated with air or oxygen discharge enhanced the growth of wheat seedlings, suggesting the potential for reusing plasma-treated wastewater in agriculture. This study enhances our understanding of the underlying mechanisms involved in the plasma degradation of SAs and reveals the significant potential of plasma technology as a sustainable approach for treating wastewater.

Investigation of highly efficient CO2 hydrogenation at ambient conditions using dielectric barrier discharge plasma

The increasing utilization of CO2 for synthesizing high-value fuels or essential chemicals is a potentially effective approach to mitigating global warming and climate change. Compared to thermal catalytic CO2 conversion under hash operating conditions (400∼500°C, 10 MPa), non-thermal plasma can overcome kinetic barriers and trigger reactions beyond thermal equilibrium at ambient temperature and pressure. In this study, the effects of operating conditions (discharge frequency, input power, and gas flow rate) and geometrical parameters (discharge length, discharge gap, and dielectric materials) have been extensively analyzed using typical cylindrical dielectric barrier discharge (DBD) plasma. The discharge characteristics changed by operating conditions (including waveforms of applied voltage and current) are compared, indicating higher applied voltage and lower gas flow rate can strengthen the filamentary discharges. The results demonstrate CO2 conversion rate increases with the increase of applied voltage and the decrease of CO2/H2 ratio, achieving its maximum value of 43.0% at 20 mL/min. The highest energy efficiency of 3771.9 μg/kJ for CO generation is obtained at the applied voltage of 5.5 kV and gas flow rate of 40 mL/min, respectively. Besides, the constructure of plasma reactor also impacts the performance of CO2 conversion. On the one hand, the discharge gap has a significant role in the variation of CO2 conversion and product selectivity, which is attributed to the electric field density and corresponding electron-induced reaction. On the other hand, the circulating water-cooling jacket was used to find out the influence of reaction temperature, which switched the product from CO to CH4. This work will pave the way for a sustainable alternative towards future CO2 conversion and utilization.

Effect of cold plasma on the physicochemical characteristics of granular cold water swelling maize starch

Granular cold water swelling (GCWS) starch is a physically modified starch with several potential applications in instant foods. Recently, some studies have revealed the beneficial effects of cold plasma (CP) treatment on improving the functional properties of starch. However, the effects of CP on GCWS has not been addressed yet. Therefore, this study assessed the influence of dielectric barrier discharge (DBD) cold plasma treatment time (1, 2, 3, and 4 min) on various attributes of GCWS maize starch. Increasing the CP treatment time increased the water absorption, solubility, viscosity, and freeze-thaw stability of GCWS maize starch, while, decreased its relative crystallinity and turbidity. FTIR results indicated that the functional groups along backbone remained unchanged upon CP treatment. Morphological analysis revealed that the starch granules preserved their integrity during CP treatment. However, increasing the duration of CP treatment resulted in the formation of micro-cavities and fissures on the surface of GCWS starch granules. The textural and rheological characteristics of GCWS starch pastes were improved by CP treatment. It seems that CP treatment might lead to an interconnected structure within the starch network and reinforce the starch paste.

Improved ultrafiltration performance through dielectric barrier discharge/sulfite pretreatment: Effects of water matrices and mechanistic insights

The feasibility of utilizing a dielectric barrier discharge (DBD)/sulfite-ultrafiltration system was investigated in various real water bodies, aiming to clarify the mechanism behind alleviating membrane fouling while synchronously degrading perfluorooctanoic acid (PFOA) during the treatment process of Yangtze River water. The results demonstrated that the DBD/sulfite pretreatment exhibited remarkable rates of membrane flux mitigation (>84.10%) and efficient degradation rates of PFOA (>85.13%), which decreased with increasing pH from 3.0 to 11.0. The presence of anions, cations, and natural organic matter slightly hindered the membrane fouling mitigation and PFOA degradation by quenching free radicals; however, the addition of SO42− had a negligible impact. The mitigation of membrane fouling was attributed to the significant involvement of various radicals, including hydroxyl radical (•OH), sulfate radical (SO4•−), electron (e−/eaq−), su-peroxide anion radicals (•O2−), and other radicals such as SO3•−, exhibiting respective contributions of 33.25%, 28.49%, 20.56%, 11.32%, and 6.39% in a synergistic redox effect. The pretreatment effectively reduced standard blocking and cake filtration fouling mechanisms by creating a sparse fouling layer on the membrane surface while increasing its roughness. Additionally, the main active species that played a significant role in the degradation of PFOA were identified as SO4•−, •OH, and eaq−. These species contributed approximately 43.63%, 24.39%, and 20.65% respectively to the degradation process. By employing mass spectrometry and density functional theory, a proposed pathway for PFOA degradation was established, effectively reducing the toxicity associated with its degradation byproducts. This study provides innovative insights into membrane-based water treatment technologies that effectively tackle both membrane fouling mitigation and PFOA degradation.

Application of Atmospheric Cold Plasma (ACP) for Processing of Raw Bovine Colostrum: Investigation of Antimicrobial Efficacy of Different ACP Treatments

As a rich source of bioactive components, bovine colostrum (BC)1 can be used to produce valuable nutraceuticals. Achieving this goal with common thermal pasteurization processes is challenging due to the heat-sensitive nature of raw BC. This research aimed to investigate the potential of atmospheric cold plasma (ACP) as a novel non-thermal process in inactivating the microbial population in BC. Raw BC was treated with different ACP treatments, including direct dielectric barrier discharge (DBD) in both static and continuous modes, indirect DBD, corona discharge, and gliding arc discharge. The occurrence of creaming and curdling of BC during the treatments was one of the challenges of this research, which was the most and least severe during static and continuous treatments, respectively. The continuous and the indirect DBD treatments were the most and least effective in terms of microbial inactivation. The inactivation of natural microflora with the continuous ACP at the voltage of 15 kV for 20 min was approximately 98%. The indirect DBD treatment led to an increase in the microbial population of BC. In addition, the initial microbial population significantly affected the antimicrobial efficacy of ACP. Treatment voltage and time had a significant effect on the creaming and curdling, natural microflora population, and the total coliform population of the treated samples. The voltage of 14.5 kV and the exposure time of 14.2 min were determined as optimal treatment conditions by response surface methodology (RSM) to achieve the maximum reduction of microbial population, without pH changing of ACP-treated BC. The optimal treatment conditions of ACP reduced the total plate count and total coliform count of raw BC by 1.41 and 3.55 log CFU/ml, respectively, with a minor change in pH. These results promise the potential of ACP technology for BC processing.

New perspectives of atmospheric pressure dielectric barrier discharges for the deposition of thin films: From uncontrolled amorphous plasma-polymer layers to chemically patterned and crystalline (in)organic coatings

New perspectives of atmospheric pressure dielectric barrier discharges for the deposition of thin films: From uncontrolled amorphous plasma-polymer layers to chemically patterned and crystalline (in)organic coatings

Dielectric Barrier Discharge plasma-assisted construction of LDH containing multiple defects for photocatalytic degradation of tetracycline

Dielectric Barrier Discharge plasma-assisted construction of LDH containing multiple defects for photocatalytic degradation of tetracycline