Dielectric Barrier Discharge System Research Articles

ZnCo2O4 composite catalyst accelerated removal of phenylic contaminants containing of Cr(VI) in dielectric barrier discharge reactor: Process and mechanism study

The degradation of phenylic contaminants (phenol, hydroquinone, nitrobenzene, p-nitrophenol) containing Cr(VI) has been investigated in a dielectric barrier discharge (DBD) system using a ZnCo2O4 composite catalyst. The ZnCo2O4 nanowires combined with multi-walled carbon nanotubes (MWNTs) on a sponge substrate in the discharge system can induce a decrease in the corona inception voltage and discharge becomes more stable resulting in an improvement in the energy utilization efficiency. With the synergistic degradation of phenylic species containing Cr(VI), the total elimination efficiency was further improved. The active substances (H2O2 and O3) were detected in the discharged solution, and some of them were consumed in the phenylic system. The effects of ·OH, O2·- and e− were also verified using free radical trapping experiments in which ·OH exhibited the main oxidation effect for the degradation of phenylic pollutants, and e−, H2O2 and H· affect the reduction of Cr(VI). The intermediate products were determined in order to analyze the degradation process of phenylic pollutants by the ZnCo2O4 composite catalyst in combination with the DBD system. The electron transfer process in the ZnCo2O4 composite catalyst during discharge was analyzed. Finally, the biotoxicity of the phenylic pollutants before and after degradation was compared.

Dielectric Barrier Discharge Plasma Coupled with Catalysis for Organic Wastewater Treatment: A Review

Dielectric barrier discharge (DBD) plasma in advanced oxidation technology can degrade organic pollutants in water under mild conditions. It has the advantages of universality, simple reaction conditions, and no secondary pollution. However, the light, electrons, and low-reactive substances generated during the discharge process cannot be fully utilized, which limits the further application of DBD plasma. Therefore, the DBD system coupled with catalysis can not only solve the above problem, but also transforms the low-active substances into high-active substances and improves the degradation rate of organic pollutants. Based on this fact, this review focuses on the characteristics and principles of DBD plasma coupled with photocatalysis, adsorption, Fenton oxidation, persulfate oxidation and composite technology to treat organic wastewater. This review puts forward some problems of DBD synergetic catalysis technology, and looks forward to the future development direction of this technology to treat organic pollutants in water.

Synergistic catalysis of Cu-CeO2@CA composite film in a circulating DBD plasma system and its effect on ciprofloxacin degradation

In this paper, degradation of ciprofloxacin (CIP) in a circulating dielectric barrier discharge (DBD) plasma system with Cu-CeO2@CA composite films addition was investigated. The Cu-CeO2@CA films were synthesized through hydrothermal method, and the samples were characterized by SEM, XRD, EDS, FT-IR and Raman spectra analysis. The obtained results show that there was synergistic effect of the DBD plasma and the Cu-CeO2@CA films on the CIP degradation and mineralization. The optimal performance was obtained under the condition of 5 wt% Cu-CeO2 nanoparticles doping in the composite film. Besides the effect of the DBD plasma, the Cu-CeO2@CA films could drive the O3 decomposition, photocatalysis and then the more reactive oxygen species (ROS) formation. The presence of the main active species and their contributions to the CIP degradation were determined by electron spin resonance (ESR) analysis and radical quenching experiments. Methods of UV–vis spectrum, three-dimensional fluorescence spectrum and liquid chromatography mass spectrometry (LC-MS) were used to analyze the CIP decomposition process. The prepared Cu-CeO2@CA composite films had certain stability in the four cycles of application and the film catalyst was convenient for recycling. The toxicity evaluation results indicated the decline of the solution toxicity after treating in the Cu-CeO2@CA/DBD system.

Study the Effect of Dielectric Barrier Discharge (DBD) Plasma on the Decomposition of Volatile Organic Compounds

Recently, research has focused on non-thermal plasma (NTP) technologies as a way to remove volatile organic compounds from the air stream, due to its distinctive qualities, which include a quick reaction at room temperature. In this work, the properties of the plasma generated by the dielectric barrier discharge (DBD) system and by a glass insulator were studied. Plasma was generated at different voltages (3, 4, 6, 7, 8 kV ) with a fixed distance between the electrodes of 5 mm, and a constant argon gas flow rate of (2.5) I/min. DBD plasma emission spectra were recorded for each voltage. The Boltzmann plot method was used to calculate the electron temperature in the plasma ( ), and the Stark expansion method was used to calculate the electron density ( ). The decomposition of organic compounds (cyclohexane) was also studied using DBD plasma. The results showed that the potential difference between the two electrodes has a clear effect on the plasma parameters, as the temperature of the electrons and the density of electrons increase with the increase in the potential difference between the two electrodes. The DBD plasma system proved to be a good way to decompose volatile organic compounds, as the results proved the emission of hydrogen gas as one of the dissociation products of cyclohexane.

Enhanced sulfadiazine degradation in a multi-electrode paralleling DBD plasma system coupled with ZnO/cellulose acetate films

Catalysis of the ZnO/cellulose acetate (CA) films in a multi-electrode paralleling dielectric barrier discharge (DBD) system for sulfadiazine (SDZ) degradation was investigated in this study. The catalysis was induced by the multiple physical and chemical effects produced during the DBD process. The obtained results on the reactive species formation revealed that the more O3, •OH as well as 1O2 could be formed by the addition of the ZnO/CA films into the DBD plasma system. The optimal additive conditions of the catalyst were 4 pieces of 3% the ZnO/CA films addition. There was a better catalytic effect of the ZnO/CA films than the equal amount of the nano ZnO powder addition. The ZnO/CA films still took on the catalytic activity after four cycles usage in the DBD plasma system. The possible degradation pathways were also speculated by analyzing the inorganic and organic intermediates formed during the SDZ degradation.

Inner surface modification of polyethylene tubing induced by dielectric barrier discharge plasma

Dielectric barrier discharge (DBD) offers an attractive alternative to conventional wet chemical approaches for surface modification of polymer materials while inducing adhesive or wettability properties in small diameter tubes. A DBD plasma apparatus was developed in this work to induce modification to the inner surface of microbore tubing with the capability for continuous treatment. This study investigates the effects of deposited plasma power and treatment time on surface roughness and wettability induced by the DBD system. The developed system successfully demonstrates the ability to generate a broad range of surface roughness, size and density of induced surface features, and contact angles. Additional evidence of mechanical adhesion of poly(lactic-coglycolic acid) to the induced surface features is also observed.

Catalytic Hydrogen Evolution from H2S Cracking over CrxZnS Catalyst in a Cylindrical Single-Layered Dielectric Barrier Discharge Plasma Reactor.

The use of non-thermal plasma technology in producing green fuels is a much-appreciated environmentally friendly approach. In this study, an Al2O3-supported CrxZnS semiconductor catalyst was tested for hydrogen evolution from hydrogen sulfide (H2S) gas by using a single-layered dielectric barrier discharge (DBD) system. The Al2O3-supported CrxZnS catalyst (x = 0.20, 0.25, and 0.30) was produced by using a co-impregnation method and characterized for its structural and photocatalytic characteristics. The discharge column of the DBD system was filled with this catalyst and fed with hydrogen sulfide and argon gas. The DBD plasma was sustained with a fixed AC source of 10 kV where plasma produced species and UV radiations activated the catalyst to break H2S molecules under ambient conditions. The catalyst (hexagonal-cubic-sphalerite structure) showed an inverse relationship between the band gap and the dopant concentration. The hydrogen evolution decreased with an increase in dopant concentration in the nanocomposite. The Cr0.20ZnS catalyst showed excellent photocatalytic activity under the DBD exposure by delivering 100% conversion efficiency of H2S into hydrogen. The conversion decreased to 96% and 90% in case of Cr0.25ZnS and Cr0.30ZnS, respectively.

Power dependence of reactive species generation in a water falling film dielectric barrier discharge system

The short-lived and long-lived reactive species generated in plasma-liquid interactions determine their potential applications in wastewater purification and plant growth stimulation. In this work, plasma-generated reactive species including hydroxyl radicals (∙OH), hydrogen peroxide (H2O2), ozone (O3), hydronium (H3O+), and nitrate (NO3-) were quantified in a water falling film dielectric barrier discharge system. The reaction kinetics of short-lived ∙OH were analyzed based on the quantification of ∙OH and degradation of salicylic acid, focusing on the contribution and utilization of ∙OH. The interconversion of ∙OH with H2O2 and O3 was also calculated. The accumulation rates of H3O+ and NO3- indicated the potential of this dielectric barrier discharge system in sustainable fertilizer production. In addition, the toxicity prediction of salicylic acid degradation intermediates and the cultivation of soybean seeds verified the feasibility of plasma-liquid interactions in organic wastewater recycling.

Short-time cold atmospheric pressure plasma exposure can kill all life stages of the poultry red mite, Dermanyssus gallinae, under laboratory conditions

In the present study, the acaricidal effects of cold atmospheric pressure plasma treatment on poultry red mites of different developmental stages have been investigated under laboratory conditions using a dielectric barrier discharge system. A total of 1890 poultry red mites and 90 mite eggs, respectively, were exposed to the plasma under various parameter settings with a single plasma pulse generated using the gas mixture of the ambient air at atmospheric pressure. The results showed that all developmental stages of the poultry red mite could be killed by cold atmospheric pressure plasma treatment. Plasma exposure to mite eggs resulted in a complete 100% hatch inhibition regardless of the parameter settings. Post-exposure mortality rates of larvae, nymphs and adults showed significant differences after utilization of plasma at 10 W for 1.0 s. In addition, the mortality rate increased with progressing time after plasma exposure. An average mortality rate of 99.7% was observed after 12 h in all mites exposed to plasma, regardless of the selected plasma parameter, developmental stage, and nutritional status of the mites. Cold atmospheric pressure plasma has an acaricidal effect on all developmental stages of Dermanyssus gallinae, suggesting that it could be developed to an effective method for the control of poultry red mites in laying hen husbandry.

Formation of honeycomb-Kagome hexagonal superlattice pattern with dark discharges in dielectric barrier discharge

A honeycomb-Kagome hexagonal superlattice pattern with dark discharges is observed in a dielectric barrier discharge system for the first time. The spatiotemporal structure of the honeycomb-Kagome hexagonal superlattice pattern with dark discharges is investigated by an intensified charge-coupled device and the photomultipliers show that it is an interleaving of three different sub-lattices, which are bright-spot, invisible honeycomb lattice, and Kagome lattice with invisible frameworks and dim-spots, respectively. The invisible honeycomb lattices and Kagome lattices are actually composed of dark discharges. By using the optical emission spectra method, it is found that the plasma parameters of the three different sub-lattices are different. The influence of the dark discharges on pattern formation is discussed. The results may have significance for the investigation of the dark discharges and will accelerate the development of self-organized pattern dynamics.

SF 6 catalytic degradation in a γ‐Al 2 O 3 packed bed plasma system: A combined experimental and theoretical study

Effective abatement of the greenhouse gas sulphur hexafluoride (SF6) waste is of great importance for the environment protection. This work investigates the size effect and the surface properties of γ-Al2O3 pellets on SF6 degradation in a packed bed dielectric barrier discharge (PB-DBD) system. Experimental results show that decreasing the packing size improves the filamentary discharges and promotes the ignition and the maintenance of plasma, enhancing the degradation performance at low input powers. However, too small packing pellets decrease the gas residence time and reduce the degradation efficiency, especially for the input power beyond 80 W. Besides, lowering the packing size promotes the generation of SO2, while reduces the yields of S-O-F products, corresponding to a better degradation. After the discharge, the pellet surface becomes smoother with the appearance of S and F elements. Density functional theory calculations show that SF6 is likely to be adsorbed at the AlIII site over the γ-Al2O3(110) surface, and it is much more easily to decompose than in the gas phase. The fluorine gaseous products can decompose and stably adsorb on the pellet surface to change the surface element composition. This work provides a better understanding of SF6 degradation in a PB-DBD system.

Influence of Dielectric Media on the Plasma Characteristics in DBD Discharge

The study of the surface plasma characteristics under atmospheric pressure is a new branch and tool in physics. Building generation dielectric barrier discharge (DBD) system at atmospheric pressure and studying its thermal characterizations. The discharge was produced by applying a high voltage of 20 kV with a frequency of 8 kHz. The thermal characterization was done by measuring discharge temperature for different horizontal surface areas and different types of insulating material. The results indicated that the effect of the area and the type of insulator affect the discharge (increasing or decreasing) according to the operation conditions because they affect, as expected, the DBD . The plasma temperature increased with the decrease of the surface area, which resulted in the increase of the discharge voltage across the gap; accordingly, the discharge across the gap grew.

Enhanced removal of Cr(Ⅵ) from wastewater by dielectric barrier discharge plasma coupled with TiO2/rGO nanocomposites: Catalytic performance and reduction mechanism

Dielectric barrier discharge (DBD) plasma system coupled with titanium dioxide/reduced graphene oxide (TiO2/rGO) nanocomposites for enhanced hexavalent chromium (Cr(Ⅵ)) reduction has explored. TiO2/rGO nanocomposites were prepared by a modified hydrothermal method. The characterization of morphology, structure and optical properties showed that the TiO2/rGO nanocomposites could be successfully synthesized with large specific surface area and high charge carrier separation rate. The effects of the discharge voltage, initial concentration and solution pH on the reduction of Cr(Ⅵ) in the alone DBD system were experimentally analyzed. The results exhibited that the reduction efficiency of 100 mg/L Cr(Ⅵ) was 100% after 55 min discharge treatment at the discharge voltage 22 kV and at pH = 2. Moreover, the results of the DBD-TiO2/rGO system showed that the Cr(Ⅵ) reduction efficiency was greatly improved from 72% to 100% after 40 min discharge treatment with adding 0.3 g/L TiO2/rGO-5 nanocomposite, indicating the TiO2/rGO nanocomposites exhibited greatly synergistic effect with DBD plasma. To illustrate the mechanism of Cr(Ⅵ) reduction in DBD combined with TiO2/rGO nanocomposites, quenching tests were performed by adding active species scavengers and the concentrations of H2O2 and O3 were also detected. Photogenerated electrons, •O2– and photo-generated H2O2 were found to play a vital role in accelerating the reduction of Cr(Ⅵ) to Cr(III).

Oxidative removal of hexane from the gas stream by dielectric barrier discharge reactor and effect of gas environment

The removal of hexane from a gas stream using a dielectric barrier discharge (DBD) reactor was conducted at ambient temperature and atmospheric pressure. The role of N2, dry and humidified air carrier gases were investigated in terms of removal efficiency and product selectivity. The oxygen concentration was also varied over the range of 0 – 21% at constant power and residence time in an N2O2 mixture for further insight into oxygen's role. A semi-empirical model of NTP-decomposition in the presence of O2, N2 and H2O is proposed. It was observed that hexane removal efficiency and product selectivity increased with increasing plasma power, regardless of the carrier gas used. The maximum removal efficiency (hexane) was 94.4% in the humidified air carrier gas. The introduction of water vapour with a relative humidity of 25% at 20 °C in the plasma DBD system significantly increased the hexane removal efficiency and CO2 selectivity (84.7%) while eliminating the production of solid residue and O3. This was probably due to the action of OH radicals. Increasing O2 concentration from 0 to 21% increased the removal efficiency and CO2 selectivity due to the generation of oxygen radicals. The results imply that the decomposition of hexane by non-thermal plasma DBDs is dominated by the effect of OH and O radicals. A semi-empirical model shows that the non-thermal plasma decomposition of hexane is first order. The DBD reactor has been demonstrated to be an effective and promising technology for removing hexane emissions from air streams. The effects of N2, O2 and H2O have been quantified, and mechanisms for their action proposed.

Plasma-catalytic biogas reforming for hydrogen production over K-promoted Ni/Al2O3 catalysts: Effect of K-loading

Biogas reforming for hydrogen production was achieved in a tabular dielectric barrier discharge (DBD) system using K-promoted Ni/Al2O3 catalysts with varying potassium loadings. The Ni–K/Al2O3 catalyst with 2 wt% K loading showed the best reforming performance with a CH4 conversion of 32% and a CO2 conversion of 23%, resulting in the highest energy efficiency of 0.67 mmol kJ−1 among the studied catalysts. In comparison to the unpromoted Ni/Al2O3 catalyst, the presence of 2 wt% potassium loading enhanced H2 production while suppressing CO formation, increasing the relative amount of H2 in the syngas. Furthermore, the Ni–K/Al2O3 catalyst (2 wt% K) exhibited the most pronounced plasma-catalytic synergy. The results of thermal gravimetry analysis (TGA) revealed that increasing potassium loading in the catalysts increased carbon production by generating more inactive and less active carbonaceous species (Cγ and Cβ) on the catalyst surfaces. This study demonstrates that by tuning the potassium loading of Ni/Al2O3 based catalysts, the performance of plasma-catalytic biogas reforming at low temperatures can be enhanced.

Study of Some Plasma Characteristics in Dielectric Barrier Discharge (DBD) System

In this present paper, an experimental study of some plasma characteristics in dielectric barrier discharge (DBD) system using several variables, such as different frequencies and using two different electrodes metals(aluminium (Al) and copper (Cu)), is represented. The discharge plasma was produced by an AC power supply source of 6 and 7 kHz frequencies for the nitrogen gas spectrum and for two different electrodes metals(Al and Cu). Optical emission spectrometer was used to study plasma properties (such as electron temperature ( ), electron number density ( ), Debye length ( ), and plasma frequency ( )). In addition, images were analysed for the plasma emission intensity at atmospheric air pressure.

Cold plasma treatment of porous scaffolds: Design principles

AbstractThree‐dimensional porous scaffolds have the potential to revolutionize a number of fields, including stem cell research, biomedical implants, tissue engineering, and regeneration, as well as energy technologies, filtration, and sensing. The ability to precisely engineer their surface properties is paramount to successful and enduring application. Plasma treatments promise to deliver homogeneous surfaces with tailored characteristics while generating few by‐products and not relying on the diffusion of liquids into a porous network. However, forming plasma inside complex interconnected pores is a significant challenge and requires much parameter fine‐tuning. This study uses numerical modeling to investigate key parameters which affect plasma breakdown and makes practical recommendations for achieving treatment homogeneity. We consider a dielectric barrier discharge (DBD) system, where nitrogen gas flows through a glass tube containing a porous scaffold, which is surrounded by a cylindrical electrode, with ground electrodes at either end of the tube. The parameters investigated include the scaffolds' pore size and porosity as well as electrode size and position. The results showed that homogeneous treatment is achieved by avoiding alternative breakdown pathways such as a poor seal between the scaffold and the glass containment tube, using a narrow supply electrode centered at the scaffold, and positioning ground electrodes as close as possible to the supply electrode without arcing. This strategy maximizes the electric field strength at a given voltage, allowing for higher pressures to be used, which in turn give a more homogeneous mean free path inside the pores.

In-duct grating-like dielectric barrier discharge system for air disinfection

In the context of spreading Coronavirus disease 2019 (COVID-19), the combination of heating, ventilation, and air-conditioning (HVAC) system with air disinfection device is an effective way to reduce transmissible infections. Atmospheric-pressure non-equilibrium plasma is an emerging technique for fast pathogen aerosol abatement. In this work, in-duct disinfectors based on grating-like dielectric barrier discharge (DBD) plasmas with varied electrode arrangements were established and evaluated. The highest airborne bacterial inactivation efficiency was achieved by ‘vertical’ structure, namely when aerosol was in direct contact with the discharge region, at a given discharge power. For all reactors, the efficiency was linearly correlated to the discharge power (R2 =0.929–0.994). The effects of environmental factors were examined. Decreased airflow rates boosted the efficiency, which reached 99.8% at the velocity of 0.5 m/s with an aerosol residence time of ~3.6 ms. Increasing humidity (relative humidity (RH)=20–60%) contributed to inactivation efficacy, while high humidity (RH=70%−90%) led to a saturated efficiency, possibly due to the disruption of discharge uniformity. As suggested by the plasma effluent treatment and scavenger experiments, gaseous short-lived chemical species or charged particles were concluded as the major agents accounting for bacterial inactivation. This research provides new hints for air disinfection by DBD plasmas.

Influence of Non-Thermal Plasma (DBD) On Infertility Male Semen with Low Sperm Motility and Dna Damage

Non-thermal plasma(Dielectric barrier discharge) has many uses including living tissue sterilization, inactivation of the bacteria, excimer formation, angiogenesis, and surface treatment. This research aim is to use cold plasma as a tool to search the effect of the dielectric barrier discharge system at room temperature on human sperm motility and DNA integrity. This work was performed on 60 human semen samples suffering from low motility; each sample was prepared by centrifugation method, then each semen sample was divided into two sections, the first section is before significant exposure to the plasma system (DBD) and the second section is after treatment with the DBD system at ambient temperature. Before and after exposure to non-thermal Plasma (DBD), DNA integrity and sperm motility were assessed, patients suffered from asthenospermia has a high level of DNA fragmentation than fertile male, ( 24.16±4.14) p<0.001 for untreated and after treatment the semen slide with dielectric barrier discharge the percentage decreases to (9.16±1.76) p>0.006, and the comet slide was (35.44±4.15) then the percentage decline to (19.86 ±2.44) these results have shown that cold plasma improves sperm motility and decreases from DNA damage in patients with medium and high level of DNA damage.

Promoting the reduction of CO2 to formate and formaldehyde via gas–liquid interface dielectric barrier discharge using a Zn0.5Cd0.5S/CoP/multiwalled carbon nanotubes catalyst

A Zn0.5Cd0.5S (ZCS) solid solution was prepared using a hydrothermal method, in which CoP nanowires were added as a co-catalyst and co-deposited with multiwalled carbon nanotubes (MWNTs) on sponge to prepare a series of ZCS/CoP/MWNTs/sponge electrodes. The microstructures of catalysts were analyzed to confirm ZCS and CoP were successfully loaded in MWNTs/sponge. The CO2 reduction products (formate and formaldehyde) produced via dielectric barrier discharge (DBD) using the different catalysts proved that the introduction of the CoP nanowires co-catalyst can enhance the catalytic activity of ZCS/MWNTs/sponge in the DBD system. Using 10% CoP and a ZCS/CoP concentration of 2.5 g·L−1, the resulting ZCS/CoP/MWNTs/sponge catalyst exhibited the best catalytic of CO2 reduction ability toward formate (7894.6 μmol·L−1) and formaldehyde (308.5 μmol·L−1) after 60 min of discharge, respectively. The proposed DBD catalytic mechanism for the reduction of CO2 was analyzed according to the Tafel slope, density functional theory calculations, photocurrent density and plasma reaction process. Furthermore, the application of the DBD catalytic technology for CO2 capture and reduction was shown to be efficient in a seawater system, and as such, it could be useful for marine CO2 storage and conversion.