Arc Discharge System Research Articles

Arc Discharge Synthesis of Chitosan‐Mediated Copper Nanoparticles for Heterogeneous Catalysis in 4‐Nitrophenol Degradation

AbstractCopper nanoparticles (Cu‐NPs) have garnered substantial interest in the field of nanotechnology due to their exceptional physical and chemical properties and cost‐effectiveness. However, challenges such as particle aggregation and rapid copper oxidation affect nanoscale production. This study systematically investigates the synthesis of colloidal Cu‐NPs using chitosan (Cts) as a stabilizer and reducing agent in the arc discharge system, comparing it to distilled water as a medium. Confirmation of the purity, size, and morphology of the Cu‐NPs is achieved through various physicochemical characterization methods. X‐ray diffraction patterns confirm the synthesis of highly pure face‐centered cubic (fcc) crystal Cu‐NPs. UV–vis analysis reveals absorption peaks at 572–585 nm, indicating pure copper. Fourier‐transform infrared spectroscopy shows peaks at 638 and 597 cm−1, corresponding to Cu─Cts bonds. Transmission electron microscopy images depict spherical nanoparticles ranging from 15 to 45 nm, with smaller sizes at higher Cts concentrations. The catalytic activity of Cu‐NPs in the degradation of 4‐nitrophenol to 4‐aminophenol is assessed, with Cu‐NPs synthesized in distilled water demonstrating superior catalytic properties compared to 0.10 wt.% Cts. This study highlights the efficacy of the arc discharge method in producing pure, uniformly sized Cu‐NPs with potential applications in catalysis.

The effect of magnetic field variations on the spectral properties of tornado plasma

At atmospheric pressure and at a frequency of 9.1 kHz, a constructed magnetically stabilized tornado gliding arc discharge (MSGAD) system was utilized in this study to generate a non-thermal plasma with an alternating voltage source from 2,4,6,8 to 10 kV. Argon gas was used to generate the arc plasma with an adjustable flow rate using a flow meter regulator to stabilize the gas flow rate to 2 L/min. A gliding plasma discharge is achieved by a magnetic field for the purpose of a planned investigation. The influence of the magnetically stabilized tornado gliding arc discharge parameters such as magnetic field and applied voltage on microscopic tornado plasma parameters was studied. The electron temperature1was measured using a Boltzmann plot and the electron1density was1determined by the Stark1broadening method. The electron temperature ranged from 0.818 eV to 1.495 eV, and the electron density varied from 1.37 × 1018 cm−3 to 2.49 × 10 18 cm−3 at a magnetic coil with 350 turns. Subsequently, the electron temperature increased to a range of 1.029 eV–1.794 eV, and the electron density reached a range of 1.53 × 1018 cm−3 to 2.89 × 1018 cm−3 at a magnetic coil with 500 turns. It can be observed that the plasma properties exhibit a rise as the number of turns of the coil and the applied voltage increase.

Effect of Working Gas and Applied Voltage on the Estimation of Power and Electron Density in Gliding Arc Discharge (GAD) System

Abstract: Atmospheric pressure gliding arc plasma is generated by a 50 Hz (0-13 kV) AC power supply. The electrical properties of the produced plasma are investigated with the help of an oscilloscope. In this work, the relationship between applied voltage, breakdown voltage, and discharge current is studied for air, argon, oxygen, and nitrogen gases. Similarly, the effect of the nature of gases on breakdown voltage and discharge current is studied. The power consumed by the discharge for different gases is obtained by current-voltage characteristics. It is found that among air, nitrogen, argon, and oxygen, argon consumes minimum and nitrogen consumes maximum power. Specifically, at the maximum applied voltage of 10.2 kV, oxygen and nitrogen consume approximately 56-57% more power than argon. Electron density, one of the most essential plasma parameters, is evaluated and compared using an electrical approach for several fading gases. The electron density is found to be increasing with the increase in applied voltage, and the value of electron density is found to be larger in argon discharge. Keywords: Gliding arc discharge, I–V characteristics, Power consumption, Discharge voltage, Electron density.

Underwater Arc Discharge Treatment Using a High-Voltage Arc-Robust Supply

Underwater arc discharge is one of the most effective water treatment methods because of the effects of intense shockwaves and high ultraviolet radiations. In this paper, a high-voltage underwater arc discharge system is proposed to study the inactivation of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Escherichia coli</i> bacteria, which has an arc-robust feature. It consists of a high-voltage capacitor charger and a discharge circuit. The high-voltage capacitor charger is developed by an LCCL resonant converter to reach a current supply scheme that is inherently protected and robust against arc discharge. The detailed mathematical analysis and the design optimization of the resonant converter are presented. The discharge circuit is developed by a two-step spark gap scheme using an ultrafast highvoltage trigger circuit, providing a reliable system operation independent of the water conductivity. The proposed underwater arc discharge system is applied to 500ml of pollutant water to study the system’s performance on the inactivation of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E. Coli</i> bacteria. The proper microbiological tests are carried out, showing the effectiveness of the proposed underwater arc discharge system. The complete inactivation of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E. Coli</i> bacteria is achieved in an extremely short treatment time. Moreover, the experimental results are presented, which validate the desired performance of the proposed underwater arc discharge system.

Improvements in Germination and Growth of Sprouts Irrigated Using Plasma Activated Water (PAW)

The extensive use of chemical fertilizers to increase crop yields in agricultural fields has had a negative impact on the environment. To produce more food on less land and fulfill the growing global demand for food, farmers will need innovative and environmentally friendly technology. Several studies have cited the positive effects of plasma-activated water (PAW) on seeds in their research findings. This study investigates the effects of PAW on four distinct seed species: phapar (Fagopyrum esculentum), barley (Hordeum vulgare), mustard (Brassica nigra), and rayo (Brassica juncea). Deionized (DI) water was treated for 5 or 10 min using the gliding arc discharge (GAD) system, which was operated by line frequency in the air. Water analysis indicates that the physiochemical parameters (electrical conductivity, pH, nitrate, nitrite, and ammonia concentration) of PAW were significantly different from DI water. Despite exposure to GAD for a certain period of time, the temperature of DI water did not alter significantly. All calculated germination parameters were significantly enhanced for seeds treated with PAW compared to the control. In addition, they displayed a significant increase in total seedling length and exhibited greater vigor. Seeds immersed in PAW absorbed significantly more water than seeds soaked in DI water, enabling rapid water penetration into the seed and early seedling emergence. This puts plasma agriculture ahead of conventional farming methods.

Arc and pulsed spark discharge inactivation of pathogenic P. aeruginosa, S. aureus, M. canis, T. mentagrophytes, and C. albicans microorganisms.

There is a strong and ever-escalating need for sterilization tools that are effective against a broad range of pathogenic microorganisms. To address this issue, this study evaluates the inactivation potential of arc and pulsed spark plasma discharges on Pseudomonas aeruginosa, Staphylococcus aureus, Microsporum canis, Trichophyton mentagrophytes, and Candida albicans microorganisms. Our results show that the electrical discharge plasma systems are effective in the inactivation of pathogenic microorganisms. The inactivation of the considered strains was greatly affected by the type of microorganisms. Higher viability losses of the pathogenic strains were observed in bacterial strains than in the fungal strains. Moreover, in the case of fungal strains, the population of C. albicans was decreased the most, followed by Trichophyton mentagrophyte, while the population of Microsporum canis was decreased the least. Besides, the arc discharge system was compared with the pulsed spark discharge system. It can be obtained from the results that the pulsed spark discharge treatment successfully enhanced the reduction of the pathogenic cells more than the arc discharge treatment. The higher efficiency of the pulsed spark discharge is due to the generation of discharge streamers on the water surface. The SEM analyses showed that electrical discharge plasmas produced serious damage to pathogenic eukaryotic and prokaryotic microorganisms. Also, the plasma-induced changes in pH values and temperature values were measured. The pulsed spark discharge-treated samples have more significant changes in pH value while arc discharge-treated samples have larger temperature changes.

A new model for the synthesis of graphite encapsulated nickel nanoparticles when using organic compounds in an arc-discharge system

Herein we propose a new “three-step” model of synthesizing graphite encapsulated nickel nanoparticles (Ni-GEM), including the pyrolysis reaction of organic compounds which the conventional two-step model ignores. According to the results of XRD, Raman, and TEM, we found that the Ni-GEM synthesized by using both PF resin and benzene vapor as the carbon sources has two favorable characteristics: thicker shells (~5–10 nm) and smaller particle sizes (~30 nm), which are much better than those using only PF resin or PF resin mixed with cyclohexane vapor (thinner shell less than 5 nm and larger particle sizes ~50 nm). Benzene decomposes into large aromatic molecules and tiny graphitic flakes at 1200–3500K, while cyclohexane prefers to decompose and form small hydrocarbon molecules at 1000K. As a result, the two compounds go through two different reaction paths. Benzene will decompose and directly attach onto the surface of Ni nanoparticles, forming smaller sized but thicker shell structured Ni-GEM, while cyclohexane will lead to the formation of amorphous carbon coating on the Ni-GEM. By including the above two distinct hydrocarbon pyrolysis reactions, this study modifies the conventional model and successfully explains the formation processes of Ni-GEM with very different morphologies. Furthermore, the new model may help in controlling the morphologies of other GEM nanoparticles with a number of core-metals.

Synthesis of multiwall carbon nanotubes in presence of magnetic field using underwater arc discharge system

In present work, we have used the underwater arc-discharge to synthesize carbon nanotubes (CNTs). Copper rod and graphite rode are used as a cathode and anode, respectively for CNTs synthesis. In addition to the DC current of 50 amp, a perpendicular magnetic field is also applied across the electrodes while producing CNTs. The CNTs are characterized using X-ray diffraction (XRD), FTIR and RAMAN spectroscopy. We have found that the MWCNTs synthesized in the presence of both electric and magnetic field have a smaller diameter compared to conventional arc discharge method.

Efficient chemical vapour deposition and arc discharge system for production of carbon nano-tubes on a gram scale.

Three indigenous systems-the underwater arc discharge setup, the inert environment arc discharge system, and the chemical vapor deposition (CVD) system-for the gram-scale production of carbon nanotubes were designed and fabricated. In this study, a detailed description of the development and fabrication of these systems is given. Carbon nanotubes were synthesized by using all the three systems, and comparative analyses of the morphology, composition, and purity were done. The synthesized materials were characterized using scanning electron microscopy, X-ray diffraction (XRD), and Raman spectroscopy. The scanning electron microscopy images show agglomerated tubed fiberlike structures in samples from the arc discharge setup, whereas samples from the CVD system do not show any tubelike structures decorated around the carbon nanotubes. Structural investigations done using powder XRD revealed the presence of the hexagonal crystallographic phase. Furthermore, the presence of the G and 2D bands reveals sp2 hybridization and confirms the presence of carbon nanotubes in samples. In conclusion, carbon nanotubes synthesized via the CVD system is of high quality and quantity. Moreover, the CVD is a cheap, easy to operate, and energy-saving synthesis method compared with the other two methods.

Deuterium ion beam formation in a vacuum arc discharge system with a deuterated cathode

The formation of deuterium ion beams in a vacuum arc with a deuterium-saturated zirconium cathode was studied using a MevvaV.Ru vacuum arc ion source. The multi-aperture ion-optical system of the source was replaced by a string ion-optical system to measure and compare the current–voltage characteristics and current density distributions over the beam cross-section obtained with the two systems. The study shows that the string system with a deuterated cathode provides a beam current 1.4–1.5 times higher than the multi-aperture system does, all other things being equal, and that the beam divergence with the string system is also higher. The total pulse current of deuterium ions in the beam ranges to about 1 A.

Ion beam measurements for the investigation of TiN thin films deposited on different substrates by vacuum arc discharge

Titanium nitride thin films were deposited on different substrates using vacuum arc discharge system. Simultaneous ion beam analysis measurements including elastic backscattering (EBS) and nuclear reaction analysis (NRA); were applied for both composition analysis and thickness measurements of the prepared TiN films. Experimental conditions have been optimized to avoid overlapping of peaks of different nuclear reactions products, especially those related to interaction between ion beam and light elements present in totally different substrates. Independent compliment measurements utilizing time-of-flight elastic recoil detection analysis (TOF-ERDA), scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) measurements were also applied to verify the experimental findings obtained by EBS and NRA measurements. The results have shown that all prepared TiN films have N/Ti ratio of around 1, with low levels of contamination elements.

Reforming of CO2-containing natural gas with steam in AC gliding arc discharge for hydrogen production

ABSTRACTIn this study, a low-temperature gliding arc discharge system was used to investigate the effects of steam content and operational parameters, i.e. total feed flow rate, applied voltage, and input frequency, on the reforming performance of CO2-containing natural gas. The addition of steam less than 10% was found to enhance both selectivities for hydrogen and carbon monoxide with a significant reduction of power consumptions. The highest hydrogen selectivity and yield with the lowest power consumptions were achieved at a steam content of 10 mol%, a total feed flow rate of 100 cm3/min (corresponding to a very short residence time of 1.37 s), an applied voltage of 13.5 kV and an input frequency of 300 Hz. Under these optimum conditions, the oxidative dehydrogenation reactions to produce hydrogen were dominant with the minimum activities of all undesired reactions of cracking and coupling. Both of the short residence time (1.37 s) with a low bulk temperature (lower than 200°C) in the plasma zone under atmospheric pressure, indicate that the studied plasma reactor (gliding arc system) is superior to conventional catalytic reactors for reforming of natural gas.

Fabrication of graphene from graphite by a thermal assisted vacuum arc discharge system

In this study, graphene was fabricated on copper foils using a high temperature furnace embedded in a vacuum arc discharge method. Combining the advantages of chemical vapor deposition and vacuum arc discharge, single-layer graphene can be fabricated at 600 °C base temperature from the mini furnace embedded with a fast heating via the photon radiation from the vacuum arc to 1100 °C on the substrates' surface. The optimal fabrication condition was determined through a series of experiments on ambient pressure, processing time, arc currents, and the cooling process. Observations by scanning electron microscopy, Raman spectroscopy, and optical microscopy showed that the main products were single-layer graphene, which has a uniform thickness across the entire substrate. The results demonstrated that the combination of a vacuum arc with a thermal method that uses graphite as a carbon source provides a low-cost and straight forward method to synthesize graphene films for graphene-based applications.

Fullerenes synthesis by combined resistive heating and arc discharge techniques.

The two main electrode techniques for fullerenes production; the direct arc technique and the resistive heating of graphite rod were employed in this work. One of the electrodes was resistively heated to high temperature and subjected to arc discharge along its length by the second graphite rod. Fullerenes solid were extracted from carbon soot samples collected from an installed arc discharge system using the solvent extraction method. The fullerenes solid obtained from carbon soot collected for 2 min of arc discharge run when one of the electrodes was resistively heated at different voltages all gave higher yields (maximum of 67 % higher, at 150 A arc current and 200 Torr chamber pressure) compared to when no resistive heating was carried out. Scanning electron microscopy and ultraviolet visible spectroscopy analysis carried out on all fullerenes solid indicated the presence of fullerenes. The enhancement of fullerenes production by combined resistive and direct arc techniques shows prospect for possible use at industrial level for large scale production.

Preparation of carbon nanoparticles by plasma arc discharge under fluidized dynamic equilibrium

Continuous preparation of carbon nanoparticles by dielectric barrier discharge (DBD)-induced non-thermal plasma arc discharge with large spacing in a modified fluidized bed is presented. Discharge arc is generated via the inducement of DBD which provides conductive media in order to realize a large spacing arc discharge. Three kinds of flow conditions defined as full circulation, fluidized dynamic equilibrium, and full collection are determined by the relationship of critical fluidized velocity and the real gas velocity after some modification of the fluidized bed. Movement model of carbon nanoparticles has been proposed to illustrate the flow conditions. A visualized and comprehensive refinement of aggregating processes has been exhibited and proved by high-resolution transmission electron microscopy. Simplified equivalent electrical conductive model of the arc discharge system is successful to generally and perspicuously figure out the discharge process which is impeded by the generated carbon nanoparticles. Effects of flow conditions and flow ratio of carrier gas/carbon source on morphology and yield of nanoparticles have been analyzed by morphology observation and yield calculation along with modeling the process.

Low-cost foil metallization using arc discharge for passivated emitter and rear solar cells

For the cost reduction of passivated emitter and rear cells (PERC), we propose a new rear contact formation method, in which an aluminum foil and an arc discharge system are used. The arc discharge system consists of inexpensive parts and does not contain any sophisticated part such as a laser ablation apparatus. Therefore, this system can save the cost of the rear contact forming process. We applied this technique to a test production of PERC. It is found that the arc discharge system can provide a similar performance to that attained by a conventional PERC production method.

Gas Flow Dependence on Dynamic Behavior of Serpentine Plasma in Gliding Arc Discharge System

Gliding arc discharge systems have been used in various applications. However, the power of conventional gliding arc plasmas is relatively high and the system requires an additional discharge for its ignition and a resistor for current protection, which causes further total energy consumption. We have proposed ultraviolet (UV)-assisted gliding arc discharge systems supported by time-resolved understanding for electrical characteristics and dynamic behavior of serpentine plasmas. In this paper, we report on gas flow dependence on dynamic behavior of serpentine plasmas in a gliding arc discharge system with the irradiation of a low-pressure mercury lamp. Time-resolved evaluation was carried out using the results of synchronized measurement for serpentine plasmas with a high-speed camera, a high-voltage probe, and a current sensor. Waveforms and mean values of the applied voltage, current, power, impedance, and energy for serpentine plasmas in the UV-assisted gliding arc discharge system were studied. The power and impedance per unit plasma length were also evaluated.

Efficient Synthesis of Endohedral Metallofullerenes in 3-Phase Arc Discharge

Endohedral metallofullerenes and, in particular, trimetallic nitride endohedral metallofullerenes exhibit unique properties that differentiate them from other carbon nanomaterials. Future applications of these species are restricted due to high cost and low productivity of existing synthesis methods, which are primarily based on the use of a Krätschmer-Huffman two electrode in-line arc discharge reactor with packed electrodes. We have developed an alternative way for the synthesis of metallofullerenes that employs a 3-phase arc discharge system. The method has been validated and optimized for the synthesis of trimetallic nitride endohedral metallofullerenes, including Lu3N@C80. Experimental results have shown more than 400% increase in Lu3N@C80 yield and productivity, while eliminating the use of high cost process gases (i.e., helium). Moreover, a metal oxide powder feed and solid graphite electrodes are introduced to avoid the need for packed electrodes and to extend reactor run times.

Synthesis Gas Production by Combined Reforming of CO2-Containing Natural Gas with Steam and Partial Oxidation in a Multistage Gliding Arc Discharge System

In this research, the effect of multistage gliding arc discharge system on the process performance of combined natural gas reforming with steam and partial oxidation has been investigated. The simulated natural gas used in this study contains 70% methane, 5% ethane, 5% propane, and 20% carbon dioxide. An increase in stage number of gliding arc reactors from 1 to 3, at a constant feed flow rate, enhances all reactant conversions and H2 yield with a substantial reduction of energy consumption. However, at a given residence time, an increase in stage number from 1 to 3 shows no effect on any hydrocarbon reactant conversions or the selectivities for H2 and CO but has a drastic reduction of energy consumption. For either the constant feed flow rate or the constant residence time, 3 stages are found to be an optimum stage number of gliding arc reactors for synthesis gas production from the reforming of CO2-containing natural gas with steam and partial oxidation, in terms of the lowest specific energy consumptio...

An electron source with a multiarc plasma emitter for obtaining submillisecond pulsed megawatt beams

An electron source with a plasma emitter based on an arc-discharge system with six cathodes and a common cylindrical hollow anode is described. Upon synchronous initiation of vacuum-arc discharges, the space of the hollow anode is filled by dense low-temperature plasma, the emission boundary of which is stabilized by a fine-structure metal grid with a 150-cm2 area. The arc-current amplitude for each cathode amounts to 100–300 A. Under the action of a constant accelerating voltage applied between the plasma emitter and grounded accelerating electrode combined with the drift tube, electrons are extracted from plasma and accelerated. At a working pressure of 0.04 Pa, an electron beam with a maximum current amplitude of 1 kA has been obtained at an initial accelerating voltage of 80 kV and pulse duration (FWHM) of 100 μs, which has been transported in a longitudinal magnetic field of 0.035 T over a distance of 80 cm.