Oxygen Dielectric Barrier Discharge Research Articles

Surface activation of viscose textiles via air, argon, and oxygen dielectric barrier discharge plasma: influence of peak voltage

This paper discusses the use of atmospheric pressure dielectric barrier discharge (DBD) plasma treatment to enhance the surface qualities of viscose fabrics. The study explores the effects of different plasma gases, discharge voltages, and exposure times on the treated fabrics. The findings emphasize the importance of optimizing the plasma’s peak voltage to achieve the desired surface treatment outcomes. The document also presents data on colour strength, wettability, colour fastness, and tensile strength of the treated fabrics, as well as scanning electron microscopy (SEM) analysis of surface morphology and chemical analysis using fourier- transition infrared spectroscopy (FTIR) and energy dispersive X-ray (EDX). The results show that treatment at a peak voltage of 11.83 kV is more efficient, except for the tensile strength which is enhanced at a peak voltage of 8.92 kV. The oxygen plasma treatment significantly improves the colour strength, which exhibits an increase from 11 to 18. The intensified colour was attributed to the significant influence of electrostatic interactions between the charged hydroxyl groups of the oxygen plasma treated viscose textiles and the dye molecules, which enhance the printability. The oxygen DBD plasma exhibits a higher ability to enhance the properties of textiles when compared to air and argon plasmas. This study presents a sustainable, economical, secure, and ecologically friendly approach to explore new fabrics for specific uses.

Regeneration of oxygenated functional groups on thermally reduced graphene oxide nanosheets via diluted oxygen DBD cold plasma

Although stacked graphene oxide (GO) possesses abundant oxygenated functional groups, it suffers from limited specific surface area. This study aims to enhance the specific surface area of graphene oxide via thermal expansion and subsequently oxygenated functional groups using a dielectric barrier discharge (DBD) cold plasma. GO was synthesized via improved Hummer's method, followed by rGO reduction at 520 ℃. The rGO was treated by DBD cold plasma with N2 and O2 gases at various powers and exposure times. The resulting samples were characterized using several techniques, including TPD, FTIR, Boehm titration, BET, Raman spectroscopy, FESEM and EDS. The results showed that increasing O2 in the feed gas up to 47 % and plasma power enhanced oxygenated functional groups on plasma-functionalized rGO (PF-rGO). The exposure time significantly influenced the oxygen content of the functional groups; PF-rGO samples with 5 min exposure time exhibited superior specific surface area, water stability, and Cd2+ adsorption capacity compared to samples treated for 15 min. As plasma exposure time increased, layer stacking and oxygenated group density increased. Raman spectroscopy confirmed the enhancement of oxygen groups on the rGO surface treated with O2-N2 plasma. These findings provide valuable insights for designing and developing of graphene-based materials with tailored properties and enhanced performance for energy-related applications.

Kinetics of Paracetamol Degradation in Aqueous Solution by the Action of Dielectric Barrier Discharge in Oxygen

Kinetics of Paracetamol Degradation in Aqueous Solution by the Action of Dielectric Barrier Discharge in Oxygen

Kinetics of Paracetamol Degradation in Aqueous Solution by the Action of Dielectric Barrier Discharge in Oxygen

The kinetics of decomposition of paracetamol in its aqueous solution by the action of atmosphericpressure dielectric barrier discharge (DBD) in oxygen has been studied. Degradation rate constants, energy yields, and degrees of degradation have been determined for various discharge powers and paracetamol concentrations. It is shown that the degradation products are carboxylic acids, aldehydes, CO, and CO2.

Effect of non-thermal oxygen-DBD plasma treatment on reducing the phthalate leach and in improving the mechanical strength properties of polymethyl methacrylate denture base and denture liner

Phthalates and esters of aromatic carboxylic acids are used as plasticizers in certain denture soft-lining materials and tissue conditioners. The presence of phthalates is of concern, because they may induce undesirable biological effects such as hormonal disorders, reproductive toxicity, hepatocellular tumours, genital disorders owing to a capacity to bind oestrogen receptors. Despite the potential risk posed by phthalates, their use in denture and denture liner is unavoidable due to the lack of efficient substituent material. Varied curing cycles, solvent wash, thermal plasma treatment/curing, etc., are some of the methods used to eliminate the phthalate content. The use of varied curing cycles, thermal plasma curing etc., will harm the polymer matrix of the acrylic denture resulting in further complication of the acrylic-liner interface bond architecture such as increased wettability, formation of pores, formation of gas pockets, micro fractures at the edges, etc. Hence, in order to overcome the above mentioned, curing of the materials under non thermal Oxygen dielectric barrier discharge (NT-O2/DBD) plasma is suggested. Sets of research samples prepared and lined with PDMS liners (as per ISO 178) were treated with NT-O2/DBD plasma. The treated samples were subjected to mechanical strength tests and calorimetric phthalate leach test. The results indicated that NT-O2/DBD plasma reduced the phthalate content remarkably and improved the overall mechanical strength properties when compared to the controls (thermal plasma treated and heat cured samples).

Water Purification to Remove Naphthalene by Treatment with Dielectric-Barrier Discharge in Oxygen

Water Purification to Remove Naphthalene by Treatment with Dielectric-Barrier Discharge in Oxygen

Kinetics of 1,4-Dichlorobenzene Decomposition in an Atmospheric Pressure Dielectric Barrier Discharge in Oxygen

The kinetics of decomposition of 1,4-dichlorobenzene vapor in an atmospheric pressure dielectric barrier discharge in oxygen has been studied. It has been found that the degree of decomposition decreased with the gas flow rate and initial concentration and increased with the discharge power. The apparent rate constants of degradation have been determined, and the energy efficiency of the process has been estimated. The maximum degree of decomposition reached 90%, and the energy yield of decomposition was 2.7 × 10–3 molecules per 100 eV. The main gaseous products of the degradation were СО2, Сl2, carboxylic acids, and aldehydes. The degradation was accompanied by the formation of a polymer film on the reactor walls. Elemental analysis has shown that the film contains C (60 wt %), O (38%), and Cl (2.3%). The IR spectra show that the film contains fragments of carboxylic acids. A comparison of the experimental results with previously obtained data for 2,4-dichlorophenol has shown that the kinetic laws are similar for both of the compounds.

Activation of p53-Mediated Apoptosis Pathway in HSC3 Cancer Cell Irradiated by Atmospheric DBD Oxygen Plasma

Oral cancer cell HSC3 is inactivated by the direct irradiation of oxygen plasma generated by torch-type oxygen dielectric barrier discharge. Selective inactivation of the cancer cells is observed at the discharge voltage of 4.2 kV, where normal cells suffer no damages from the plasma. Inactivation mechanism of HSC3 cells irradiated by the plasma is considered as the apoptosis. Activation of mitogen-activated protein kinase and p53 proteins owing to the phosphorylation is one of the pathways to the cancer cell apoptosis.

The Destruction of Carbon Tetrachloride Dissolved in Water in a Dielectric Barrier Discharge in Oxygen

The kinetics of decomposition of tetrachloromethane (TCM) in its aqueous solutions and the kinetics of decomposition products formation was investigated under the action of DBD at atmospheric pressure in oxygen in a falling-flow reactor. The range of initial concentrations of TCM was 25–325 μmol/l, the discharge power—2–11 W and O2 flow rates—1–3 cm3/s. It is shown that the kinetics of the TCM decomposition can be described by the equation of pseudo-first kinetic order. The rate constant depended weakly on the discharge parameters and was ~ 5 s−1. The energy efficiency of the decomposition, depending on the parameters, was 0.1–1.3 molecules per 100 eV. When the residence time of the solution with the discharge zone is more than 1 s, it is possible to achieve almost 100% degree of TCM decomposition. It is shown that the main products of the TCM decomposition in the liquid phase are aldehydes and Cl− ions, and in the gas phase—the molecules CO and CO2. The results for energy efficiency are compared with the results obtained in other AOP’s processes (Fenton process, photocatalytic process, the radiation process by the action of high-energy electron flux). It is shown that the action of the DBD is more effective than the action of the above processes.

NUMERICAL STUDY OF GAS HEATING IN OZONE GENERATED BY DBD IN OXYGEN

The goal of the present work is to highlight the gas temperature effect in ozone generated by dielectric barrier discharge (DBD) in pure oxygen (O2). In this study, a one-dimensional fluid model was used to describe the discharge behavior. The study of the gas heating phenomena study in the frame of this paper is due to the gas heating effect. The gas temperature profile obtained in the DBD in oxygen was calculated by means of the heat transport equation. The results show that the rise of the gas temperature in the DBD inoxygen is more important near the dielectrics. The high value of gas temperature in this region is limited by the increase in the electric field and ion current density.

Modification of Metallic Multiwalled Carbon Nanotubes Properties by 50 Hz Atmospheric Pressure Dielectric Barrier Discharge Plasma

In this study, multiwalled carbon nanotubes (MWCNTs) were modified using low frequency (50 Hz) nonequilibrium plasma, which was generated separately by oxygen and nitrogen dielectric barrier discharge plasma (DBD) at atmospheric pressure. The MWCNTs were treated with oxygen and nitrogen DBD plasma at atmospheric pressure under three different applied voltages, because the MWCNTs surface was closely related to the plasma treatment voltage. The surface and electrical properties of pristine and treated MWCNTs were studied using Transmission Electron Microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy, while the electrical characteristics were measured using a Hall measurement and two-point probe. FTIR showed formation of oxygen-containing groups like C=O and COOH for the O2 DBD plasma, and addition of N–H vibration bending for the N2 DBD plasma. Raman spectroscopy revealed that the ratio of I D/I G increased with increasing discharge voltage of plasma. The ascended I D/I G may be ascribed to the production of several new defects owing to the introduction of oxygen- and nitrogen functional groups recognized by FTIR. The results of Hall measurement showed that the hall mobility increased with the increase of O2 and N2 DBD voltage. Highest hall mobility was measured for MWCNTs treated with nitrogen at 12 kV, which was 172.9 cm2/Vs. It was also found from the two-point probe IV curve that Ohmic behaviour of pristine MWCNTs tended to change to Schottky behaviour after DBD plasma treatment.

Surface modification of core-shell silk/PVA nanofibers by oxygen dielectric barrier discharge plasma: Studies of physico-chemical properties and drug release behavior

Bombyx mori silk fibroin (BMSF), a natural protein polymer, has increasingly gained research interest as promising biomaterial in drug delivery application due to its excellent biological and physiochemical properties. In this study, antibiotic loaded silk/PVA core-shell nanofibers has been prepared followed by surface modification using homogeneous oxygen (O2) dielectric barrier discharge (DBD) plasma at atmospheric pressure. Polyvinyl alcohol (PVA) is used as the shell material whereas amoxicillin trihydrate is loaded into the silk solution (AMOX-BMSF) and the mixture is used as core material for fabricating core-shell nanofibers. O2 DBD plasma treatment induces surface hydrophilicity in AMOX-BMSF/PVA nanofibers due to incorporation of polar functional groups onto the surface as revealed from X-ray photoelectron spectroscopy (XPS) analyses. The O2 DBD plasma treatment facilitates formation of hydrogen bonds on the surface of the nanofibers resulting in better mechanical behavior of the nanofibers. The DBD plasma treated nanofibers show relatively faster biphasic drug profile than the untreated nanofibers with prolonged antibacterial activities against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria. The results demonstrate that O2 DBD plasma surface modified AMOX-BMSF/PVA nanofibers can be explored as mechanically enhanced wound dressing in treatment of skin and wound Infections.

DESTRUCTION OF OIL HYDROCARBONS IN WATER SOLUTIONS WITH OXYGEN DIELECTRIC BARRIER DISCHARGE OF ATMOSPHERIC PRESSURE

This paper reports the experimental study of destruction kinetics of oil hydrocarbons (engine oil of the M8 trademark) dissolved in water by dielectric barrier discharge in oxygen at the atmospheric pressure. The range of initial concentrations of oil in the aqueous solution was (12- 91) mg/l. All experiments were carried out under the applied voltage of 7.9 kV and discharge current of 0.45 mA (rms values) with a frequency of 50 Hz. The inputted power was 0.35 W/cm3. The gas flow rate was 1 l/min. It was shown that the kinetics of oil decomposition can be formally described by the pseudo-first order law on oil concentration. The effective rate constant for decomposition of petroleum products was 0.0016 s-1. The rate of destruction in the investigated concentration range of M8 was varied in the range (3.8 - 28.9) · 10-6 mol / (l·min). The oil decomposition degree achieved 80 %, and the decomposition energetic yield was 0.16 molecules per 100 eV of inputted energy. The kinetics of the formation of ozone and carbon dioxide was examined as well. The obtained experimental data allowed to determine the degree of completeness of oil oxidation, which at the maximum was 54% (for carbon dioxide), this results indicates the formation of other carbon-containing compounds. The dynamics of the change in the pH of the treated solution is revealed. Under the experimental conditions, the pH was reduced from 6 to 4. It was found that the concentration of ozone formed in the reactor was deficiency for oil oxidative degradation. This results confirms that in the system are formed other active particles involved in the destruction of petroleum products, such as the OH* radicals and atomic oxygen. The possible mechanism of degradation processes is discussed.Forcitation:Grinevich V.I., Rybkin V.V., Lyubimov V.A., Gushchin A.A. Destruction of oil hydrocarbons in water solutions with oxygen dielectric barrier discharge of atmospheric pressure. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 8. P. 20-27.

Plasmachemical and heterogeneous processes in ozonizers with oxygen activation by a dielectric barrier discharge

Plasmachemical and heterogeneous processes of generation and loss of ozone in the atmosphericpressure dielectric barrier discharge in oxygen are studied theoretically. Plasmachemical and electronic kinetics in the stage of development and decay of a single plasma filament (microdischarge) are calculated numerically with and without allowance for the effects of ozone vibrational excitation and high initial ozone concentration. The developed analytical approach is applied to determine the output ozone concentration taking into account ozone heterogeneous losses on the Al2O3 dielectric surface. Using the results of quantummechanical calculations by the method of density functional theory, a multistage catalytic mechanism of heterogeneous ozone loss based on the initial passivation of a pure Al2O3 surface by ozone and the subsequent interaction of O3 molecules with the passivated surface is proposed. It is shown that the conversion reaction 2O3 → 3O2 of a gas-phase ozone molecule with a physically adsorbed ozone molecule can result in the saturation of the maximum achievable ozone concentration at high specific energy depositions, the nonstationarity of the output ozone concentration, and its dependence on the prehistory of ozonizer operation.

Atmospheric-pressure DBD plasma-assisted surface modification of polymethyl methacrylate: A study on cell growth/proliferation and antibacterial properties

This paper reports polymethyl methacrylate (PMMA) surface modification by atmospheric-pressure oxygen dielectric barrier discharge (DBD) plasma to improve its biocompatibility and antibacterial effects. The role of plasma system parameters, such as electrode gap, treatment time and applied voltage, on the surface characteristics and biological responses was studied. The surface characteristics of PMMA films before and after the plasma treatments were analyzed by water contact angle (WCA) goniometry, atomic force microscopy (AFM) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Also, acid–base approach was used for evaluation of surface free energy (SFE) and its components. Stability of plasma treatment or aging effect was examined by repeating water contact angle measurements in a period of 9 days after treatment. Moreover, the antibacterial properties of samples were investigated by bacterial adhesion assay against Escherichia coli. Additionally, all samples were tested for the biocompatibility by cell viability assay of mouse embryonic fibroblast. WCA measurements indicated that the surface wettability of PMMA films was improved by increasing surface free energy via oxygen DBD plasma treatments. AFM measurement revealed that surface roughness was slightly increased after treatments, and ATR-FTIR analysis showed that more polar groups were introduced on the plasma-treated PMMA film surface. The results also demonstrated an enhancement of antibacterial performance of the modified surfaces. Furthermore, it was observed that plasma-treated samples exhibited significantly better biocompatibility, comparing to the pristine one.

Comparison of effects on PBO fiber by air and oxygen dielectric barrier discharge plasma

Poly(p-phenylene-2,6-benzobisoxazole) (or PBO) fibers were treated with dielectric barrier discharge plasma (DBD) using air and oxygen gas, respectively. The treatment time was set as 12s, plasma power density of air-DBD plasma was used as 10 W/cm3, 20 W/cm3, 30 W/cm3, 40 W/cm3 and 50 W/cm3. The interlaminar shear strength (ILSS) between PBO fiber and bismaleimide (BMI) resin was improved by air-DBD plasma treatment and reached its highest value 57.1 MPa at 12s, 30 W/cm3. Meanwhile, the ILSS of PBO/BMI composites treated by oxy-DBD plasma at the same condition was only 51.2 MPa. The chemical and physical changes of PBO fiber caused by plasma were studied by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), respectively. The surface polarity and reactivity of PBO fiber were enhanced by plasma treatment, the surface was roughened as well. Otherwise, the single fiber tensile strength of PBO fibers were studied, proper parameters by plasma would not decline the mechanical property evidently. These phenomena were considered as the reason of the improved ILSS. Furthermore, the water absorption of PBO/BMI composites was tested, the composites showed good humid resistance and the plasma treatment declined the water absorption of PBO/BMI composites.

Features of phenol degradation in aqueous solution in dielectric-barrier discharge in oxygen

The kinetics of phenol degradation in aqueous solution in an atmospheric-pressure dielectric-barrier discharge in oxygen at different power inputs to the discharge has been investigated. On the basis of these data, the energy yields of degradation and their dependence on the discharge parameters and initial concentration have been determined. The problem of comparing the energy efficiencies of different types of discharges has been discussed. The decomposition of phenol has been shown to result in the formation of carboxylic acids and aldehydes in the solution and carbon dioxide in the gas phase.

Influence of inert gas addition on electric breakdown using dielectric barrier discharge in oxygen

This paper studies the influence of inert gas additions He, Ar, Kr and Xe on breakdown voltage within dielectric barrier discharge reactor with oxygen feed gas. The density-normalized effective ionization coefficients α eff / N are calculated for inert gas/O 2 mixtures, the critical reduced field E/N cr is obtained where the electron ionization exactly balances the attachment. Adding inert gases would lead to the decreasing critical reduced field strength E/N cr due to the enhancement of effective ionization coefficient. In addition, inert gas additions have shown to reduce the breakdown voltage. Moreover the numerical breakdown voltage values and the experimental data are plotted for the sake of comparison and results show that calculated results are in agreement with the experimental values. Parametric study offers substantial insight in plasma physics, as well as in ozone generation applications.

An analysis of the effect of inert gases on ozone generation using dielectric barrier discharge in oxygen

This paper studies the influence of inert gases He, Ar, Kr and Xe on ozone generation in a dielectric barrier reactor fed by oxygen feed gas. Results show that inert gas additions would lead to lower applied voltage, discharge power and reduced field. The electron energy distribution function shifts to the right though inert gas addition would lead to a lower reduced field with He, Ar and Kr addition, but it shifts to the left with Xe addition. The effective electron density decreases with inert gas content. With respect to Ar/O2, Kr/O2 and Xe/O2 mixture, conversion ratio of oxygen into ozone and ozone yield would increase with increasing Ar, Kr or Xe content, the growth rates follow the order of Xe > Kr > Ar. Such behaviors can be ascribed to the fact that Ar*, Kr* and Xe* could provide another effective pathway to produce oxygen atom through penning dissociation of O2 and metastable species due to their relatively low excitation threshold and considerable rate coefficients.

Degradation of plasma-treated poly(p-phenylene benzobisoxazole) fiber and its adhesion with bismaleimide resin

Degradation of poly(p-phenylene benzobisoxazole) (PBO) fiber which was modified by oxygen dielectric barrier discharge (oxy-DBD) plasma as well as its adhesion with bismaleimide (BMI) resin were studied in this paper. Surface changes of PBO fibers before and after plasma treatment were investigated by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and single fiber tensile strength (SFTS). Aging behaviors were obviously detected upon chemical changes while the morphology and surface roughness changed little. Oxygen content and O/C ratio of the fibers reduced a lot, which were from 24.83% and 0.350 to 20.88% and 0.268 after aging in air for 30 days, respectively. Furthermore, the adhesion of oxy-DBD plasma-treated PBO fibers reinforced BMI composites dropped dramatically in the first 5 aging days but had no obviously changes during 5–30 days, and the degradation ratio was about 18%. Otherwise, the damage to the tensile strength of single fibers caused by oxy-DBD plasma can be ignored with only 4.8% reduction and showed little change during the aging time (30 days). However, the aging effects did not recover the fiber surfaces to the original state, indicating that some permanent changes were generated in the fiber surfaces. Furthermore, the water absorption varied from different composites and all the samples had good humid resistance properties.