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Non-thermal plasma has been an emerging technology for water treatment for decades. In this study, we have designed and fabricated a bubbling plasma batch reactor using an atmospheric pressure dielectric barrier discharge with a hydrophobic porous membrane. The reactor performance is assessed for purifying synthetic contaminated water samples containing chemical contaminant sulfamethoxazole (SMX), a widely used antibiotic, and biological contaminant E. coli K12. The SMX decontamination tests indicate that the degradation process is not first-order and the reaction rate dwindle with increasing initial concentration. The yield at 50% removal achieves its highest value of 8.12 g/kWh for 50 mg/L SMX sample. For inactivation of E. coli K12 tests, the inactivation process is also not first-order, and the pathogen is completely inactivated for 10 2  CFU/mL and 10 4  CFU/mL cases after 10 min and 45 min of plasma treatment, respectively. For the 10 8  CFU/mL sample, a 5-log reduction is achieved after 60 min of treatment. The developed plasma reactor can achieve fast deployment in point of use, low cost for manufacturing, and simple for maintenance. Moreover, it can be used for in-situ water purification in future long duration crewed space missions as well as tackling with water pollution issues on our planet., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Specialized chemicals are used for intensifying food production, including boosting meat and crop yields. Among the applied formulations, antibiotics and pesticides pose a severe threat to the natural balance of the ecosystem, as they either contribute to the development of multidrug resistance among pathogens or exhibit ecotoxic and mutagenic actions of a persistent character. Recently, cold atmospheric pressure plasmas (CAPPs) have emerged as promising technologies for degradation of these organic pollutants. CAPP-based technologies show eco-friendliness and potency for the removal of organic pollutants of diverse chemical formulas and different modes of action. For this reason, various types of CAPP-based systems are presented in this review and assessed in terms of their constructions, types of discharges, operating parameters, and efficiencies in the degradation of antibiotics and persistent organic pollutants. Additionally, the key role of reactive oxygen and nitrogen species (RONS) is highlighted. Moreover, optimization of the CAPP operating parameters seems crucial to effectively remove contaminants. Finally, the CAPP-related paths and technologies are further considered in terms of biological and environmental effects associated with the treatments, including changes in antibacterial properties and toxicity of the exposed solutions, as well as the potential of the CAPP-based strategies for limiting the spread of multidrug resistance.

Lipopolysaccharide (LPS) is an endotoxin composed of a polysaccharide and lipid component. It is intrinsically responsible for the pathogenicity of Gram-negative bacteria and is involved in the development of bacterial sepsis. Atmospheric pressure non-thermal plasma is proposed as a potential new approach for the treatment of infected tissue such as chronic wounds, with both antibacterial and wound-healing activities extensively described. Using both the RAW264.7 murine macrophage cell line in vitro assays and the Galleria mellonella insect in vivo toxicity model, the effect non-thermal plasma exposure on LPS-mediated toxicity has been characterised. Short (60 s) non-thermal plasma exposures of Pseudomonas aeruginosa conditioned growth media, membrane lysates and purified P. aeruginosa LPS, resulted in a substantial detoxification and reduction of LPS-induced cytotoxicity in RAW264.7 murine macrophages. Non-thermal plasma exposure (60 s) of purified P. aeruginosa LPS led to a significant (p < 0.05) improvement in the G. mellonella health index (GHI) score, a measure of in vivo toxicity. These findings demonstrate the ability of short plasma exposures to significantly reduce LPS-induced cytotoxicity both in vitro and in vivo; attenuating the toxicity of this important virulence factor intrinsic to the pathogenicity of Gram-negative bacteria., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Chronic lung infection with bacteria from the Burkholderia cepacia complex (BCC), and in particular B. cenocepacia, is associated with significant morbidity and mortality in patients with cystic fibrosis (CF). B. cenocepacia can spread from person to person and exhibits intrinsic broad-spectrum antibiotic resistance. Recently, atmospheric pressure non-thermal plasmas (APNTPs) have gained increasing attention as a novel approach to the prevention and treatment of a variety of hospital-acquired infections. In this study, we evaluated an in-house-designed kHz-driven plasma source for the treatment of biofilms of a number of clinical CF B. cenocepacia isolates. The results demonstrated that APNTP is an effective and efficient tool for the eradication of B. cenocepacia biofilms but that efficacy is highly variable across different isolates. Determination of phenotypic differences between isolates in an attempt to understand variability in plasma tolerance revealed that isolates which are highly tolerant to APNTP typically produce biofilms of greater biomass than their more sensitive counterparts. This indicates a potential role for biofilm matrix components in biofilm tolerance to APNTP exposure. Furthermore, significant isolate-dependent differences in catalase activity in planktonic bacteria positively correlated with phenotypic resistance to APNTP by isolates grown in biofilms., (Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.)

Atmospheric pressure non-thermal plasma (APNTP) has been gaining increasing interest as a new alternative antibacterial approach. Although this approach has demonstrated promising antibacterial activity, its exact mechanism of action remains unclear. Mechanistic elucidation of the antimicrobial activity will facilitate development and rational optimisation of this approach for potential medical applications. In this study, the antibacterial efficacy of an in-house-built APNTP jet was evaluated alongside an investigation of the interactions between APNTP and major cellular components in order to identify the potential cellular targets involved in plasma-mediated bacterial destruction mechanisms. The investigated plasma jet exhibited excellent, rapid antibacterial activity against a selected panel of clinically significant bacterial species including Bacillus cereus, meticillin-resistant Staphylococcus aureus (MRSA), Escherichia coli and Pseudomonas aeruginosa, all of which were completely inactivated within 2 min of plasma exposure. Plasma-mediated damaging effects were observed, to varying degrees, on all of the investigated cellular components including DNA, a model protein enzyme, and lipid membrane integrity and permeability. The antibacterial efficacy of APNTP appears to involve a multiple-target mechanism, which potentially reduces the likelihood of emergence of microbial resistance towards this promising antimicrobial approach. However, cellular membrane damage and resulting permeability perturbation was found to be the most likely rate-determining step in this mechanism., (Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.)

Cercospora leaf spot disease is a serious problem for lettuce cultivation worldwide. Cercospora lactucae-sativa, the causative agent of leaf spot disease on lettuce, was treated with non-thermal atmospheric pressure gliding arc (GA), tesla coil (TC) and dielectric barrier discharge (DBD) plasmas for the in vitro fungal inactivation of both mycelial growth and conidial germination. The fungus was exposed to the three plasmas individually for 5, 10, 15 and 20 min. The results showed that DBD plasma inactivated fungal growth during all exposure periods, and the highest inhibitory effect was caused by exposure to DBD plasma for 20 min, at 93.33% inhibition. The germination of fungal conidia was completely inactivated after exposure to all three non-thermal plasmas for 5 min, as observed 4 and 24 h after incubation. The pathogenesis of C. lactucae-sativa on lettuce after plasma treatments for 5 min was examined by spraying an inoculation of the treated conidia on lettuce. The results showed that all three plasmas reduced the disease incidence and severity compared to the non-treated control. Therefore, the non-thermal atmospheric pressure GA, TC and DBD plasmas have antifungal potential for the inactivation of C. lactucae-sativa, making them an interesting novel technology for plant disease control. [ABSTRACT FROM AUTHOR]

Antibacterial activity of atmosferic pressure non-thermal plasma (APNTP) was assessed for bacterial, yeast and mold strains. This investigation is to be considered preliminary: a second step is envisaged in which the efficacy of the technique and the device will be assessed directly on food of animal and plant origin. The strains (ATCC or wild type) of Listeria innocua, Escherichia coli, Salmonella thyphimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Proteus mirabilis (bacteria); Alternaria alternata, Aspergillus flavus, Cladosporium herbarum, Fusarium graminearum, Geotrichum candidum, Penicillium roqueforti, Rhizopus nigricans (moulds); Candida parapsilosis and Candida albicans (yeasts) were subjected to plasma plume generated by the action of electric fields with a gas mixture (oxygen and helium) delivered for 5 min at a distance of 2 cm. Types of experiments were listed as following: microorganism at concentration 1×10^8 and 1×104 cfu on PCA (Plate Count Agar); Listeria innocua and Salmonella thiphymurium at concentration 1×10^4 cfu on semi-synthetic and synthetic medium; mycetes (moulds and yeasts) at concentration 1×10^8 and 1×10^4 cfu on SDA (Sabouraud Dextrose Agar). The results obtained on the bacteria subjected to atmospheric cold plasma were evident on all the strains tested except for Proteus mirabilis (1×10^8 cfu), most evident at a concentration of 1×10^4 cfu, not only on culture media PCA but also on semi-synthetic medium and jelly meat-PCA medium. In spite of bacterial results, treatment with plasma plume did not decrease or inhibit of fungal growth. That means plasma plume was neither fungicidal nor fungistatic activities.

Transient spark (TS), a DC-driven self-pulsing discharge generating a highly reactive atmospheric pressure air plasma, was employed as a rich source of NOx. In dry air, TS generates high concentrations of NO and NO2, increasing approximately linearly with increasing input energy density (Ed), reaching 1200 and 180 ppm of NO and NO2, at Ed = 400 J/L, respectively. In humid air, the concentration of NO2 decreased down to 120 ppm in favor of HNO2 that reached approximately 100 ppm at Ed = 400 J/L. The advantage of TS is its capability of simultaneous generation of the plasma and the formation of microdroplets by the electrospray (ES) of water directly inside the discharge zone. The TS discharge can thus efficiently generate plasma-activated water (PAW) with high concentration of H2O2−(aq), NO2−(aq) and NO3−(aq), because water microdroplets significantly increase the plasma-liquid interaction interface. This enables a fast transfer of species such as NO, NO2, HNO2 from the gas into water. In this study, we compare TS with water ES in a one stage system and TS operated in dry or humid air followed by water ES in a two-stage system, and show that gaseous HNO2, rather than NO or NO2, plays a major role in the formation of NO2−(aq) in PAW that reached the concentration up to 2.7 mM. [ABSTRACT FROM AUTHOR]

This study evaluates the effectiveness of non-thermal plasma at atmospheric pressure (NTP APPJ) for treating PFAS - contaminated water in different matrices. Successful removal of several perfluoroalkyl carboxylic acids (PFCAs) (C6 to C4), perfluroalkane sulfonic acids (PFSAs) (C8 to C4) and perfluropolyethers (PFPEs) (GenX and ADONA) PFAS compounds was achieved in laboratory scale experiments. In the deionized water (DW), high removal efficiencies (> 90%) were observed for longer-chain PFAS, PFOS (99.89%), PFHxA (94.61%) and ADONA (94.83%), while shorter- chain compounds had lower removal rates. Real water samples (tap water and synthetic effluent) showed lower overall degradation percentages (8–50%) depending on compound and matrix. Short-chain PFAS displayed around 10% removal in tap water, while PFOS and GenX achieved 50% and 32% removal, respectively. Complex matrix effects influence degradation rates. Byproducts from the plasma treatment were investigated, revealing distinct degradation mechanisms for various PFAS compounds. For PFSAs and PFCAs, degradation involved electron transfer, bond breaking and subsequent reactions. Conversely, ADONA and GenX degradation initiated with ether-group cleavage, followed by additional transformation processes. Plasma-based technology shows potential for degradation of PFAS, especially for newer substitute compounds like ADONA and GenX. However, further research is needed to optimize plasma performance for complete mineralization of PFAS. This study also proposes a degradation mechanism for ADONA, marking a novel investigation into ether-group PFAS degradation with potential implications for further research and understanding toxicological implications. [Display omitted] • Application of atmospheric pressure plasma jet on PFAS contaminated water. • Study of degradation and byproducts of long and short-chain PFAS by plasma treatment of different water matrices. • Novel substances GenX and ADONA plasma treatment and possible ADONA degradation pathway and byproducts. [ABSTRACT FROM AUTHOR]

Plasma medicine is the utilization of gas ionization that might be beneficial for the treatment of burn wounds, a healthcare problem with a significant mortality rate. Due to a lack of information on the impact of plasma flux in immune cells and a high prevalence of bacterial infection in burn wounds, non-thermal argon-based plasma flux was tested on macrophages (RAW246.7) and in mouse models of burn wounds with or without Staphylococcus aureus infection. Accordingly, plasma flux enhanced reactive oxygen species (ROS), using dihydroethidium assay, and decreased abundance of NF-κB-p65 (Western blot analysis) in non-stimulating macrophages. In parallel, plasma flux upregulated IL-10 gene expression (an anti-inflammatory cytokine) in lipopolysaccharide (LPS)-induced inflammatory macrophages, while downregulating the pro-inflammatory cytokines (IL-1β and IL-6). Additionally, plasma flux improved the migratory function of fibroblasts (L929) (fibroblast scratch assay) but not fibroblast proliferation. Moreover, once daily plasma flux administration for 7 days promoted the healing process in burn wounds with or without infection (wound area and wound rank score). Additionally, plasma flux reduced tissue cytokines (TNF-α and IL-6) in burn wounds with infection and promoted collagen in burn wounds without infection. In conclusion, plasma flux induced anti-inflammatory macrophages and promoted the burn-wound healing process partly through the decrease in macrophage NF-κB. Hence, plasma flux treatment should be tested in patients with burn wounds. [ABSTRACT FROM AUTHOR]

A multi-stage dielectric barrier discharge (DBD) was used to elucidate the reaction pathway for synthesizing Mg3N2 from MgO, nitrogen, and hydrogen using atmospheric pressure plasma. Recently, ammonia has been considered as a promising carbon-free material for hydrogen storage and carrier owing to its high hydrogen density. However, the extensive use of ammonia as an energy carrier has problems with respect to transportation and storage because of its toxicity, odor, and combustibility. Therefore, we consider that Mg3N2 can solve these problems and focus on Mg3N2 synthesis by nitridation of MgO using a DBD in a N2 and H2 atmosphere instead of directly synthesizing ammonia. By investigating the Mg3N2 synthesis pathway using a multi-stage atmospheric pressure plasma, it is considered that H atoms and NH radicals reduce MgO and promote nitriding. [ABSTRACT FROM AUTHOR]

Various reactive oxygen and nitrogen species are accompanied by electrons, ultra-violet (UV) radiation, ions, photons, and electric fields in non-thermal atmospheric pressure plasma. Plasma technology is already used in diverse fields, such as biomedicine, dentistry, agriculture, ozone generation, chemical synthesis, surface treatment, and coating. Non-thermal atmospheric pressure plasma is also considered a promising technology in environmental pollution control. The degradation of organic and inorganic pollutants will be massively advanced by plasma-generated reactive species. Various investigations on the use of non-thermal atmospheric pressure plasma technology for organic wastewater purification have already been performed, and advancements are continuing to be made in this area. This work provides a critical review of the ongoing improvements related to the use of non-thermal plasma in wastewater control and outlines the operational principle, standards, parameters, and boundaries with a special focus on the degradation of organic compounds in wastewater treatment. [ABSTRACT FROM AUTHOR]

A knock intensity mitigation effect resulting from the application of dielectric barrier discharge (DBD) was experimentally demonstrated. The DBD was utilized to reform fuel–air premixtures. A rapid compression and expansion machine (RCEM) was used for the demonstration experiment. A rectangular combustion channel was installed in the RCEM's cylinder to observe flame propagation and end-gas auto-ignition behavior. The effect of the DBD was investigated by installing a plug-shaped DBD reactor in the combustion chamber. Part of the fuel-air mixture was reformed by the DBD and diffused in the chamber, and the combustion behavior was observed by a color and a monochrome high-speed camera with several different interference filters. In ordinary end-gas auto-ignition, a hot flame rapidly appears throughout the end-gas region, and generates strong pressure oscillation; whereas, in the present study, when the DBD was applied, the magnitude of the pressure oscillation decreased and a blue flame was generated in the end gas before full end-gas auto-ignition. The onset time of the blue flame, and the interval between the onset and the hot flame's appearance, depended on the fuel and initial temperature. The effect was investigated in the case of a primary reference fuel, surrogate gasoline, and n-butane lean mixture; however, though the magnitude of the effect varied, the mitigation effect was demonstrated for every fuel-air mixture. The proposed method is therefore expected to mitigate knocking in internal combustion engines and contribute to greater thermal efficiency. [ABSTRACT FROM AUTHOR]

In this work, a spark‐like plasma discharge is ignited in pure CO2 and in CO2/H2 mixtures to investigate CO formation. Power pulsing is used to limit arc formation to sustain a high current transient "spark‐like" plasma consisting of a mixed mode discharge comprising an initial current pulse ("spark") followed by a longer‐lived glow mode thorough each half cycle of the applied voltage. In pure CO2, the efficiency ranged between 20–50 % for CO2 conversions between 9–18 % for gas residence times of 100–600 ms. Adding H2 as a co‐reactant was investigated for a wide range of mixture ratios. The outlet gas was found to produce O2‐free mixtures of CO/H2/CO2. Conversion rates in CO2/H2 mixtures are found to be similar to pure CO2 at equivalent residence times. The primary role of H2 as a co‐reactant is therefore found to be the removal of O2 formed during dissociation of CO2. The energy cost of this dilution resulted in reduced efficiency for CO2 conversion (from 41 to 18 %), which is correlated to the efficiency drop found for pure CO2 conversion at lower flows. Opportunities for optimising this small volume "unit‐cell" spark reactor are encouraged by the results presented. This approach could enable deployment of serial or parallel combinations of such reactors capable of dealing cost‐effectively with the conversion of the larger CO2 and CO2/H2 volumes required in future industry applications. [ABSTRACT FROM AUTHOR]

Abstract Non-thermal plasma is getting more popular in industrial applications, mainly treatment of material surfaces. Hydrophobic coatings often suffer mechanical instability and do not function well after abrasion/scratching. In this study, non-thermal plasma jet generated at atmospheric pressure in ambient condition was applied to the hydrophobic treatment of glass surface using two precursors. Tetramethylsilane (TMS) was used to promote hydrophobicity and (3-Aminopropyl)triethoxysilane (APTES) was used to get durable mechanical strength of the coating although it is hydrophilic in character. An alternating current (AC) high voltage (operating frequency: 11.5 kHz) was used to generate plasma jet for producing a coating layer onto the soda-lime glass sample. Water contact angle of 139° and a stable mechanical strength were achieved at an optimal TMS/APTES ratio of 4.8. The coating thickness, strength and water contact angle were varied by changing treatment time, applied voltage, and carrier gas (argon) flow rate. The coating layer were characterized by atomic-force microscopy (AFM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), water contact angle (WCA), scratch test and UV/visible spectroscopy. Highlights • Robust coating on the glass by APPJ conjugated with two precursors • Coating strength depended on the flow rate, voltage, time and TMS/APTES ratio. • The coating exhibited good durability, mechanical strength and thermal stability. [ABSTRACT FROM AUTHOR]

Abstract: Plasma catalysis, the combination of non‐thermal plasma and catalyst, is a promising approach for optimizing chemical conversions as the removal of gas trace components. The various technological opportunities for the generation of atmospheric non‐thermal plasma combined with the variety of usable catalysts result in a huge amount of different experimental approaches. The aim of the presented review is to give an overview of plasma catalytic reactor designs currently discussed in literature as well as to point out technological differences and potential for up‐scaling. [ABSTRACT FROM AUTHOR]

The current and potential applications of atmospheric pressure plasmas in medicine generate an increasing need to develop safe and reliable plasma devices for patient treatment. This paper shows how the estimation of safety risks, the stability of the generated plasma, and the effectiveness in the aimed application can orientate the design process of a specific atmospheric pressure plasma device intended for clinical use. A promising plasma jet device operated with air is optimized, leading to a configuration with a more advanced design that reduces the temperature of the effluent, prevents the material degradation and improves the isolation of the high voltage components. The effects of the plasma jet treatment are investigated by chemical analysis of demineralized water and inactivation tests on E. coli cultures. [ABSTRACT FROM AUTHOR]

We review new trends of agricultural applications of atmospheric‐pressure plasmas for decontaminating agricultural products and enhancing seed germination and growth of plants and beneficial microorganisms. We classify the decontamination techniques into three kinds of treatments, which are gas‐phase, in‐liquid, and plasma‐activated liquid treatments, and introduce recent studies mainly after 2010, discussing the inactivation mechanism of microorganisms in each treatment. Likewise, we categorize the enhancement techniques into the same three kinds of treatments, and introduce the growth enhancements in detail, discussing the mechanisms and future prospects. [ABSTRACT FROM AUTHOR]

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The common utilization of antimicrobial agents in medicine and veterinary creates serious problems with multidrug resistance spreading among pathogens. Bearing this in mind, wastewaters have to be completely purified from antimicrobial agents. In this context, a dielectric barrier discharge cold atmospheric pressure plasma (DBD-CAPP) system was used in the present study as a multifunctional tool for the deactivation of nitro-based pharmacuticals such as furazolidone (FRz) and chloramphenicol (ChRP) in solutions. A direct approach was applied to this by treating solutions of the studied drugs by DBD-CAPP in the presence of the ReO 4 − ions. It was found that Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS), generated in the DBD-CAPP-treated liquid, played a dual role in the process. On the one hand, ROS and RNS led to the direct degradation of FRz and ChRP, and on the other hand, they enabled the production of Re nanoparticles (ReNPs). The produced in this manner ReNPs consisted of catalytically active Re+4, Re+6, and Re+7 species which allowed the reduction of –NO 2 groups contained in the FRz and ChRP. Unlike the DBD-CAPP, the catalytically enhanced DBD-CAPP led to almost FRz and ChRP removals from studied solutions. The catalytic boost was particularly highlighted when catalyst/DBD-CAPP was operated in the synthetic waste matrix. Re-active sites in this scenario led to the facilitated deactivation of antibiotics, achieving significantly higher FRz and ChRP removals than DBD-CAPP on its own. • A unique catalytic-reaction-discharge system was proposed. • The system combined dielectric barrier discharge and rhenium nanoparticles. • A simultaneous decomposition and reduction of antimicrobial agents were observed. • Catalytic boost enabled removal of Furazolidone and Chloramphenicol from wastewater. [ABSTRACT FROM AUTHOR]

The synergistic antimicrobial effects of plasma-processed air (PPA) and plasma-treated water (PTW), which are indirectly generated by a microwave-induced non-atmospheric pressure plasma, were investigated with the aid of proliferation assays. For this purpose, microorganisms (Listeria monocytogenes, Escherichia coli, Pectobacterium carotovorum, sporulated Bacillus atrophaeus) were cultivated as monocultures on specimens with polymeric surface structures. Both the distinct and synergistic antimicrobial potential of PPA and PTW were governed by the plasma-on time (5⁻50 s) and the treatment time of the specimens with PPA/PTW (1⁻5 min). In single PTW treatment of the bacteria, an elevation of the reduction factor with increasing treatment time could be observed (e.g., reduction factor of 2.4 to 3.0 for P. carotovorum). In comparison, the combination of PTW and subsequent PPA treatment leads to synergistic effects that are clearly not induced by longer treatment times. These findings have been valid for all bacteria (L. monocytogenes > P. carotovorum = E. coli). Controversially, the effect is reversed for endospores of B. atrophaeus. With pure PPA treatment, a strong inactivation at 50 s plasma-on time is detectable, whereas single PTW treatment shows no effect even with increasing treatment parameters. The use of synergistic effects of PTW for cleaning and PPA for drying shows a clear alternative for currently used sanitation methods in production plants. Highlights: Non-thermal atmospheric pressure microwave plasma source used indirect in two different modes—gaseous and liquid; Measurement of short and long-living nitrite and nitrate in corrosive gas PPA (plasma-processed air) and complex liquid PTW (plasma-treated water); Application of PTW and PPA in single and combined use for biological decontamination of different microorganisms.

Porous ZnO nanocrystalline films have drawn research attention due to improvement in gas sensing, adsorption, photocatalytic, and photovoltaic applications. However, scalable synthesis of porous nanostructures has been a challenge. Here, This paper reports a very easy, fast, and scalable one-step process for synthesis and deposition of porous ZnO nanocrystalline film by low-temperature atmospheric pressure plasma. The plasma is generated with radio frequency power using a metallic zinc wire as a precursor. Nanostructures have been synthesized and agglomerate to form a porous film at the substrate. Energy band structure of the deposited film has been investigated to understand the corresponding band alignment, which is relevant to many applications. An in-depth study of the grown nanostructured ZnO film has been included and characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, kelvin probe measurement, ultra-violet/visible absorption, and photoluminescence. [ABSTRACT FROM AUTHOR]

Carbon dioxide conversion upon dilution by argon and nitrogen at atmospheric pressure has been studied using a barium titanate packed bed, non-thermal plasma reactor. The results show that the packed bed reactor with the BaTiO 3 ferroelectric packing material directly contacting to electrodes provided a higher CO 2 conversion and energy efficiency than a dielectric barrier discharge reactor with and without packed materials using electrodes covered by dielectric layers. In the packed bed reactor, the CO 2 conversion increased from 19% in pure CO 2 to 36% upon diluting the CO 2 with 80% argon and to 35% with 80% nitrogen at a specific energy input ( SIE ) of 36 kJ L −1 . The energy efficiency was approximately constant at ca . 0.24 mmol kJ −1 for pure CO 2 dissociation upon increasing SIE , but decreases upon dilution by Ar and is more pronounced by N 2 . In addition to the major products of CO and O 2 , up to 100 ppm of ozone was produced in a CO 2 /Ar plasma, but not in a CO 2 /N 2 plasma where some nitrogen oxides (N 2 O, NO and NO 2 ), were observed with a total maximum concentration of 3120 ppm. Possible mechanisms are presented for the effect of Ar and N 2 on the dissociation of CO 2 and for the formation of O 3 , N 2 O and NO x based on discharge processes in the plasma and the subsequent chemistry. Electrical characterisation of the pure CO 2 , CO 2 /Ar and CO 2 /N 2 plasmas was also undertaken. The results suggest the formation of by-products can be controlled by varying the dilution gas fraction and operating conditions. [ABSTRACT FROM AUTHOR]

Non-thermal plasma (NTP) is an emerging technology of great interest because the elimination of pathogens and spoilage microorganisms and their probable use in various industrial sectors such as food and health. In this study was to evaluate the inactivation of non-thermal plasma on the survival of Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 51811 and Saccharomyces cerevisiae. Treatments of different microorganisms were conducted with cells exposed NTP generated dielectric barrier reactor (DBD) able to produce atmospheric pressure plasmas. These devices operate at 13.56 MHz and are driven by a specifically built radio frequency (RF) resonant converter. The reactors, which operate at atmospheric pressure in a He-air gas mixture at a 1.5 L min-1 flow rate, applying a 850 V voltage at different exposure times (10, 20, 40, 60, 80, 100 and 120 s). All the strains showed a reduction in viability of < 0.001 log CFU mL-1 after to exposed to plasma. The cells showed membrane damage, these effects being the main cause for microbial inactivation, caused by the action of Non-thermal plasma, which leads to membrane and/or cell wall breakdown with consecutive DNA denaturation, these being the main factors inducing microorganism death. [ABSTRACT FROM AUTHOR]

Non-thermal plasma (NTP) can induce cancer cell death which is supposed to be mediated by oxidative stress. In this work, the contribution of hydrogen peroxide (H2O2) in NTP induced lung cancer cell damage is quantitatively studied. Our results also show signification production of H2O2 in plasma activated medium (PAM). NTP treatment induce critical raising of cell death, apoptosis, and DNA double-strand breaks (DSBs) in A549 cell. NTP treatment also cause mitochondrial dysfunction and intracellular ROS production in A549 cells. Furthermore, catalase efficiently protect cells from NTP induced A549 cell damage. This work clarified the contribution of H2O2 to plasma induced cancer cell damage. [ABSTRACT FROM AUTHOR]

Results of simulation of streamers propagating along atmospheric-pressure air plasma jets formed by pulsed discharges in thin dielectric tubes are presented. The specific feature of these jets is substantial gas heating by the discharges. The hot gas, emerging from the tube, is cooled at mixing with surrounding air. The streamers are guided along the jet axis, the channel with reduced gas density. Spatial profiles of various plasma parameters inside the jet are calculated. The densities of produced oxygen and nitrogen atoms near the jet axis are one-two orders larger, while the widths of radial profiles of these species are several times smaller than those in typical helium plasma jets. [ABSTRACT FROM AUTHOR]

The combination of a sub-microsecond pulsed dielectric barrier discharge with Pd/γ-AlO catalyst was investigated for the oxidation of low concentration of methane, propene, and toluene in air at atmospheric pressure. The systematic comparison of the plasma-catalysis with the thermal-catalysis and the plasma-alone have been made for temperature window of 20-400 °C and energy deposition in the range 23-148 J L. To emphasis the reactivity of plasma produced species on the activation of the catalyst, two reactor configurations were used [in-plasma catalysis (IPC), and post-plasma catalysis (PPC)]. Fourier transform infrared spectrometer was used to follow the VOCs conversion and to quantify the mineralized products. The plasma-catalyst combination leads to higher VOCs conversion and decreases the catalyst activation temperature in both IPC and PPC configurations. For hybrid system, the light-off temperature is always lower than those observed for catalytic oxidation. In addition, the formation of the by-products such as formaldehyde, formic acid, and ozone was reduced significantly. A significant synergetic effect of hybrid plasma-catalytic system is not really observed in the presence of CH and CH. However, for CH oxidation the synergetic effect was demonstrated at low temperature (<150 °C) for the IPC configuration. [ABSTRACT FROM AUTHOR]

It has been recently demonstrated that non-thermal plasmas (NTP) can function as nanoparticle processing reactors by selectively heating particles, inducing chemical reactions and structural transformations. However, lacking in prior studies is direct comparison between NTP particle-processing and more traditional, equilibrium thermal processing. With tandem differential mobility analysis, we studied the sintering of metallic nano-aggregates as they traversed through an atmospheric pressure NTP. As a reference, sintering experiments with a tube furnace were also conducted. Silver and bismuth nano-aggregates were synthesized via gas phase reactors for experiments and were selected to represent high and low melting point metals, respectively. We found that the silver aggregate sintering behavior was similar in the plasma and the furnace systems. With increasing plasma power/furnace temperature, the sintering process can be divided into to an aggregate compaction stage, a constant mobility stage and a vaporization stage. The mobility size shift of the silver aggregates was used to estimate their equivalent temperatures in the plasma. With an aggregate sintering model, an equivalent particle sintering temperature was estimated to be 165–270 °C in the plasma as the silver aggregate mobility diameter decreased from 100 nm to 95-65 nm. In contrast to silver, due to the early onset of particle vaporization, the three stages of bismuth aggregate sintering were not as clearly discernible. The constant mobility stage was only observed in a narrow range of plasma powers for the 100 nm aggregates and was not evident for the 20 nm aggregates. Additionally, distinct patterns of bismuth particle mobility shifts were observed during plasma sintering and furnace sintering, with the plasma reactor being a more effective sintering unit. The reducing environment within the plasma and the partial oxidation of the bismuth aggregates could be the reason for the effectiveness of plasma sintering. Further measurements of the particle transmission efficiency through the plasma reactor shows that it is particle size and material dependent. • We characterized the sintering behaviors of metallic nano-aggregates in a non-thermal plasma reactor and a furnace reactor. • Silver aggregates behave similarly in the two reactors, but bismuth aggregates are more effectively sintered by the plasma. • One can estimate an equivalent particle sintering temperature in the plasma reactor through mobility shift measurements. [ABSTRACT FROM AUTHOR]

Oxidation of adsorbed toluene was investigated in a dielectric barrier discharge reactor at atmospheric pressure coupled with Ag–Mn/γ-Al 2 O 3 catalysts. Gas flow-through and gas circulation systems were compared in the same reactor with the same operating conditions. After 90 min of plasma treatment, the mineralization of adsorbed toluene reached 68% in the O 2 flow-through system with some emission of desorbed toluene. For the O 2 circulation system, the mineralization of adsorbed toluene increased to 78% without any emission of desorbed toluene. Furthermore, compared to the gas flow-through system, the CO 2 selectivity in the gas circulation system was improved in both air and oxygen plasma. Moreover, the circulation system was more efficient than the gas flow-through system for O 3 decomposition, resulting in better mineralization of adsorbed toluene and CO 2 selectivity. [ABSTRACT FROM AUTHOR]

A dielectric barrier discharge (DBD) plasma jet of neon (Ne) at atmospheric pressure and room temperatures was arranged under a high frequency ac power supply. We achieved to obtain an atmospheric pressure glow-like discharge in this study. Not only have the effects on various microorganism been reported, but also atmospheric pressure plasma using Ne has been introduced. The microorganism inactivation by means of the non-thermal plasma were studied with eight kinds of typical microorganism, i.e., Esherichia coli, Micrococcus luteus, Staphylococcus aureus, Salmonella typhimurium, Bacillus subtilis, Listeria monocytogenes, Candida albicans and Candida glabrata. Treatment time was selected as 60 s. According to the Ne emission spectra of the plasma jet and the inactivation results of microorganism after the plasma treatment, it can be discussed that the reactive species in the Ne plasma had an important role in the inactivation of microorganism. [ABSTRACT FROM AUTHOR]

This paper described a novel and green approach on catalytic ammonia synthesis using non-thermal plasma (NTP). The process studied in this paper involves the synthesis and absorption of ammonia under atmospheric pressure and low temperature. The effects of operational parameters including applied voltage, frequency, gas component and flow rate on ammonia synthesis under NTP conditions are studied in this paper. In addition, different selected catalysts and absorbents were investigated under different conditions of NTP treatment and the ammonia efficiency was reported and analyzed. Ru catalyst with carbon nanotube support, along with Cs promoter and micro porous absorbents including Molecular Sieve 13X and Amberlyst 15 yield the highest ammonia efficiency in this process. Results further indicated that frequency and applied voltage of 10,000 Hz and 6000 V, with N:H feed ratio of 3:1 provided the optimized efficiency of ammonia synthesis of 2.3 gNH/kWh. [ABSTRACT FROM AUTHOR]

In this work, the treatment of a typical insulating materials epoxy resin for improving surface hydrophobicity using an atmospheric pressure plasma jet (APPJ) in Ar/trimethyl silane (TMS) is conducted. For meeting the large area treatment requirement of complicated shape insulating surface, a jet linear array consisting of five jet units is developed. The surface properties of the epoxy resin before and after the treatments are studied using contact angle measurement, scanning electron microscopy and fourier transformed infrared spectroscopy. The effects of treatment time and TMS content on the water contact angle are investigated, and the treatment conditions for the maximum contact angle are obtained. It is found that dense mesh structure is formed on the surface and silicon-containing groups are introduced into the surface after treatments. The modified surfaces show a remarkable increase in water contact angle, and the surface hydrophobicity is improved accordingly. The maximum contact angles are obtained at treatment time of 300s and TMS content of 0.04%. [ABSTRACT FROM AUTHOR]

This study investigated the degradation of a model organic compound, reactive blue (RB-19), in aqueous solution using a needle-plate non-thermal plasma (NTP) reactor, which was operated using three gas atmospheres (Ar, air, O 2 ) at room temperature and atmospheric pressure. The relative discharge and degradation parameters, including the peak to peak applied voltage, power, ozone generation, pH, decolorization rates, energy density and the total organic carbon (TOC) reduction were analyzed to determine the various dye removal efficiencies. The decolorization rate for Ar, air and O 2 were 59.9%, 49.6% and 89.8% respectively at the energy density of 100 kJ/L. The best TOC reduction was displayed by Ar with about 8.8% decrease, and 0% with O 2 and air atmospheres. This phenomenon could be explained by the formation of OH• and O 3 in the Ar and O 2 atmospheres, which are responsible for increased mineralization and efficient decolorization. A one-dimension model was developed using software COMSOL to simulate the RB-19-ozone reaction and verify the experiments by comparing the simulated and experimental results. It was determined that ozone plays the most important role in the dye removal process, and the ozone contribution rate ranged from 0.67 to 0.82. [ABSTRACT FROM AUTHOR]

The remediation of soil, contaminated by organic pollutants, in a cylinder-to-plane dielectric barrier discharge reactor at atmospheric air pressure was reported. Two model organic pollutants were selected; a solid pollutant (2,6-dichloropyridine) and a liquid pollutant ( n-dodecane). The effects of the contaminant's initial concentration and state, the energy consumption, and the soil type on the pollutant removal efficiency were investigated. To that scope, various contaminated samples of both quartz sand and loamy sandy soil were treated by plasma for various treatment times and initial 2,6-dichloropyridine/ n-dodecane concentrations. The results revealed that (1) the removal efficiency of 2,6-dichloropyridine was higher compared to that of n-dodecane at a given plasma treatment time and (2) the removal efficiency increased with the energy density increasing, but decreased as the soil heterogeneity, organic matter and pollutant concentration were enhanced. The main removal mechanism proposed is the evaporation of pollutant molecules coupled with their oxidation by plasma species in the gas and solid/liquid phase. [ABSTRACT FROM AUTHOR]

Methane oxidation was investigated in a pulsed dielectric barrier discharge at atmospheric pressure coupled with Pd/Al 2 O 3 catalysts. Comparison between plasma, catalytic, and plasma-catalysis (both in-plasma and post-plasma catalysis) systems were performed in the temperature range of 25–500 °C and specific input energy up to 148 J/L. For plasma-alone experiments, CH 4 conversion reached a maximum of 67% and the main products obtained were CO, CO 2 , O 3 , and HNO 3 . The plasma catalytic treatment leads to an increase of the CH 4 oxidation even at low temperature. It is evidenced that, compared to plasma alone, both Al 2 O 3 and Pd/Al 2 O 3 catalysts coupled plasma discharge increase the CH 4 conversion. Moreover, for all plasma-catalytic systems, the CH 4 conversion plots were shifted toward lower temperature as the specific input energy increases. Although the difference is low, the in-plasma catalysis configuration seems to be more efficient compared to post-plasma catalysis. In all cases, CH 4 oxidation in presence of Pd/Al 2 O 3 catalyst becomes more selective in CO 2 formation than the reaction in plasma alone. [ABSTRACT FROM AUTHOR]

A dielectric barrier discharge (DBD) reactor was fabricated and operated in two steps. In the first step (oil mist collection) oil mist aerosols were collected and in the second step (oil mist-to-gas conversion), without supplying oil mist particles but with supplying only clean air flow, collected oil mist particles were converted to gas species. An aerodynamic particle sizer, a scanning mobility particle sizer system, and a real-time gas analyzer were used to measure particle and gas concentrations at the inlet and outlet of the DBD reactor. The oil mist collection efficiency decreased from 78% to 21% but the oil mist-to-gas conversion efficiency increased from 6% to 95%, with increasing frequency from 1 kHz to 10 kHz. Low frequency caused higher amplitude of oscillating particle movement between the electrodes, resulting in higher collection efficiency. At a higher frequency, more electrons were generated, which resulted in the formation of more reactive oxygen species and thus increased subsequent oxidation. Increased surface temperature of the DBD reactor with higher frequency also contributed to higher oil mist-to-gas conversion efficiency. The DBD reactor can be applied to reduce oil mists generated in metal working and cooking processes. [ABSTRACT FROM AUTHOR]

The antimicrobial effects and mechanism of helium atmospheric-pressure plasma jet (APPJ) treatment on Staphylococcus aureus biofilms are evaluated in vitro. The S. aureus biofilms are more resistant to the plasma treatment than adherent bacteria. The APPJ-treated S. aureus biofilms disclose a depth/layer-related intra-bacterial ROS accumulation effect. Plasma exposure may induce bacterial oxidative stress and trigger the production of intracellular reactive oxygen species (ROS) in the biofilms, which possibly contributes to bacteria death in addition to direct etching from the exterior of bacteria. The findings provide insights into the mechanism of biofilm inactivation by plasma reactive species and plasma-induced intracellular ROS. [ABSTRACT FROM AUTHOR]

Compared with other non-thermal plasma sources, the atmospheric-pressure plasma jet (APPJ) has advantages on simple structure, low temperatures, strong chemical activities, and convenient handling, all of which have attracted much attention. The power sources play an important role on the characteristics and the applications of the APPJ. In this article, a compact repetitive microsecond-pulse generator is designed for exciting the APPJ in helium and argon. The microsecond-pulse generator can produce repetitive pulses with output voltages of up to 20 kV, pulse width of ~8 ????s, and pulse repetition frequencies (PRFs) of 1 Hz ~2 kHz. Using the designed repetitive microsecond-pulse generator, the characteristics of the APPJ are investigated by measuring the voltages and currents and obtaining images of the discharges. Experimental results show that the microsecond-pulse generator has been successfully used to sustain stable APPJs both in helium and argon. The shape of the output voltage pulses may change as the applied voltage increases. Nevertheless, the output voltages are stable at all PRFs when the applied voltage is fixed. Furthermore, the effects of flow rate, the applied voltage, and the PRF on the He/Ar APPJ are investigated. Results show that it is more likely to generate a He APPJ rather than an Ar APPJ under microsecond-pulse excitation. The length of the plasma plume is slightly affected by the PRF both in the He APPJ and the Ar APPJ. [ABSTRACT FROM PUBLISHER]

A plane-to-grid dielectric barrier discharge (DBD) reactor operating with air at atmospheric pressure was used to investigate the removal of non-aqueous phase liquids (NAPLs) from soil layers. A mixture of n -C 10 , n -C 12 and n -C 16 was used as a model NAPL that polluted the soil at a very high initial concentration (100,000 mg/kg-soil). The effect of treatment time, energy consumption, and soil thickness on the NAPL removal efficiency was investigated, the plasma active species were identified, and the macroscopic gas temperature was determined. The NAPL remediation efficiency found to be as high as 99.9% after 60–120 s of plasma treatment, depending on soil thickness. The energy density required to remediate completely the NAPL was about 600 J/g-soil and was practically independent of the soil thickness, indicating that the DBD-based plasma has the potential to become a highly cost-effective technology for the remediation of NAPL-contaminated soils. N 2 + , N 2 ∗ , NO x and O 3 were identified as plasma-induced reactive species, a maximum gas temperature close to 300 °C was recorded, and the total carbon detected in exhaust gases, in the form of CO and CO 2 , was ca 40% of that contained in the NAPL removed from the soil. The main mechanisms of NAPL removal by plasma found to be the evaporation of organic compounds coupled with their oxidation in liquid and gas phase. Using ATR-FTIR in combination with high-throughput organic profiling analysis by GC–MS, ketones and alcohols were identified as the main intermediate products of alkanes oxidation in soil matrix. [ABSTRACT FROM AUTHOR]

Hydrophilic modification of polymethyl methacrylate (PMMA) surface is performed by atmospheric pressure plasma jet (APPJ) in Ar gas for improving the PMMA surface flashover performance in vacuum. In the experiments, APPJ is driven by a microsecond-duration pulsed generator, which has voltages of 0-30 kV, a rise time of 300 ns and a full width at half maximum of 2μs. Characteristics of the APPJ are analyzed according to its voltage and current waveform, discharge image and optical emission spectrum. Furthermore, surface properties of the PMMA surface before and after the treatment are characterized by water contact angle measurements and morphology observations. Results show that the main species of the plasma jet are composed of N2, Ar, OH, and O, among which such polar groups as OH and O enhance the hydrophilic property of the PMMA surface. The water contact angle decreases from 68° to a minimum value (16°) after the treatment. In addition, all the surface flashover voltages in vacuum for the PMMA samples treated by APPJ are higher than those for the untreated PMMA samples. [ABSTRACT FROM AUTHOR]

The influence of non-thermal plasma treatment on wheat seeds ( Triticum aestivum ) has been investigated using a surface discharge reactor at atmospheric pressure and room temperature. Growth parameters, like roots and sprouts length and dry weight were measured on the fourth day of germination and a Gaussian distribution was used for curve-fitting of the obtained results. It was found that plasma had little effect on the germination rate, but influenced growth parameters. In the case of plasma treated seeds, the distribution of roots was shifted towards higher lengths as compared with the untreated samples. The distribution of the sprouts length was about two times narrower for the treated samples as compared with the control seeds. The sprouts and roots of the plasma treated seeds were heavier than those of the control samples. The root-to-shoot (R/S) ratio differed substantially, being 0.88 ± 0.016 for the untreated seeds and reaching 1.2 ± 0.005 for the treated samples. Industrial relevance The results obtained in this research demonstrate that non-thermal plasma treatment has a positive effect on wheat early growth. Due to its advantages (uniform treatment, no destruction of seeds, no requirement for chemicals), plasma might become an effective alternative to traditional pre-sowing seed treatment used in agriculture. [ABSTRACT FROM AUTHOR]

Microbial inactivation using non-thermal gas discharge at atmospheric pressure has become a subject of significant research effort in the recent years. In this paper, we reviewed the different viewpoints proposed by various researchers, and discussed the reasons for arriving at these conclusions. We summarized some general rules, and offered a proposal to study the reasons behind their conclusions by building mathematical model for prediction of principle factors. The future prospects for the application of plasma are outlined. [ABSTRACT FROM AUTHOR]

Economic application of atmospheric pressure plasma technology for industrial pollution control requires fulfilling two propositions: First application of pollution control technologies needs to result in clear environmental, health, or safety benefits motivating political measures. Second plasma technology needs to be competitive as compared to other available pollution control technologies. Thus in this article methods for the evaluation of atmospheric plasma application for industrial pollution control are reviewed: Examples of emission regulations and emission control technologies are given. Requirements of industrial scale emission control and of thermal and non-thermal exhaust gas treatment technologies are described. The potential of various non-thermal plasma reactor concepts for cost effective treatment of industrial scale gas flows is analyzed, and methods for the evaluation of plasma energy balance and plasma chemical kinetics are given for them. How to deal with shortcomings of atmospheric pressure plasmas such as lack of plasma-chemical selectivity is addressed in a section about plasma-catalytic hybrid processes. Further the progress made recently in electrostatic precipitation is reviewed, and the importance of electro-hydrodynamic effects for the reactor design both for electrostatic precipitation and for plasma chemical pollution control is considered. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Abstract: Although the antimicrobial activity of atmospheric pressure non-thermal plasmas, including its capacity to eradicate microbial biofilms, has been gaining an ever increasing interest for different medical applications, its potential utilisation in the control of biofouling and biodeterioration has, to date, received no attention. In this study, the ability of atmospheric pressure plasma to eradicate biofilms of four biofouling bacterial species, frequently encountered in marine environments, was investigated. Biofilms were grown on both polystyrene and stainless steel surfaces before being exposed to the plasma source. Viability and biomass of biofilms were evaluated using colony count method and differential Live/Dead fluorescence staining followed by confocal laser scanning microscopy. Rapid and complete eradication of all biofilms under study was achieved after plasma exposures ranging from 60 to 120 s. Confocal microscopy examination showed that plasma treatment has mediated not only cell killing but also varying degrees of physical removal of biofilms. Further investigation and tailored development of atmospheric pressure non-thermal plasma sources for this particular application could provide an additional powerful and effective weapon in the current anti-biofouling armamentarium. [Copyright &y& Elsevier]

Positive and negative streamer discharges in atmospheric pressure air were generated in a shielded sliding discharge reactor at operating voltages as low as 5 kV for a gap length of 1.6 cm. In this reactor, electrodes are placed on top of a dielectric layer and one of the electrodes, generally the one on ground potential, is connected to a conductive layer on the opposite side of the dielectric. The energy per pulse, at the same applied voltage, was more than a factor of seven higher than that of pulsed corona discharges, and more than a factor of two higher than that of sliding discharges without a shield. It is explained on the basis of enhanced electric fields, particularly at the plasma emitting electrode. Specific input energy required for 50 % removal from ~1,000 ppm initial NO could be reduced to ~18 eV/molecule when ozone in the exhaust of negative streamers was utilized. For sliding discharges and pulsed corona discharges this value was ~25 eV/molecule and it was 35 eV/molecule for positive shielded sliding discharges. Also, the ozone energy yield from dry air was up to ~130 g/kW h and highest for negative streamer discharges in shielded sliding discharge reactors. The high energy density in negative streamer discharges in the shielded discharge reactor at the relatively low applied voltages might not only allow expansion of basic studies on negative streamers, but also open the path to industrial applications, which have so far been focused on positive streamer discharges. [ABSTRACT FROM AUTHOR]

[Display omitted] • Plasma is mainly used as a non-destructive and fast method for the functionalization of carbon nanotubes. • The nature change of the carbon nanotubes occurs via functional groups formed on nanotubes using plasma functionalization. • Plasma Functionalized carbon nanotubes can dramatically improve some properties in the polymer matrix. • The creation of active sites on nanotubes by the plasma treatment can be used for grafting with metals. The use of carbon nanotubes in a wide range of academic and industrial fields has received considerable attention due to their uniqueness in structures and properties. Despite these advantages, there are still some significant challenges and drawbacks such as insolubility which can have negative impacts on the application process. The introduction of functional groups on the surface of carbon nanotube can overcome this obstacle. Plasma functionalization can be a preferred method in comparison to other ones as a quick and relatively non-destructive, as well as environmentally-friendly method for the surface functionalization of carbon nanotubes. This review presents a brief introduction to the types, properties, and functionalization methods of carbon nanotubes for a better understanding. The focus of this review is on the modification of carbon nanotubes through different types of plasma functionalization methods, notably plasmas that operate at an ambient temperature and atmospheric pressure, to improve their properties. It also investigates the results obtained from analytical methods for plasma treated carbon nanotubes. [ABSTRACT FROM AUTHOR]

The low-current non-thermal atmospheric plasma source is a useful cost-effective tool for many applications. One of the major applications of this source is to reform hydrocarbons to produce hydrogen. Here, the focus is on the design and development of a system for this process. The system described uses much lower current compared to the other thermal plasma systems and operates at atmospheric pressure eliminating the need for an expensive vacuum system. The system consists of a plasmatron, a fuel injection system for both liquid and gaseous forms, a window for inserting diagnostics systems, and a system to collect output signals from plasma. The non-thermal plasma was produced at high pressure with an AC high-frequency power supply. A three electrode system (copper, stainless steel 314, and nickel) were used with four different configurations. Initial discharge characteristics have been measured for all electrode configurations. The breakdown properties of the system with the electrode configurations and corresponding ionization coefficient (α) have been estimated. A cylindrical Langmuir probe was used to measure and estimate relevant plasma parameters. [ABSTRACT FROM AUTHOR]