In this study, PET/ZnONP composites with varying ZnO concentrations were fabricated using an oxygen plasmaassisted method. The process involved an initial surface activation of PET via RF oxygen plasma treatment, followed by drop-coating with a ZnO colloidal solution synthesized via pulsed laser ablation of ZnO ceramics in water. Leaching tests were conducted to evaluate the potential of the fabricated PET/ZnONP composites for food packaging applications and to verify the incorporation of ZnO NPs on the PET surface. ZnO NPs were characterized using UV-Vis spectroscopy, ICP-OES spectrometry, and SEM. The PET/ZnONP composites were analyzed through water contact angle measurements, FTIR spectroscopy, Raman spectroscopy, AFM, and XPS. The antimicrobial properties of the composites were assessed against the Gram-negative Escherichia coli bacteria. Notably, at the highest ZnO NPs concentration (4.1 mg/L), nearly complete antibacterial efficacy was achieved. At this concentration, the barrier properties of the composites were also examined due to their important role in determining food shelf-life and preservation. Oxygen permeability decreased by 139-fold, while water vapor permeability did not change significantly. The shelf-life of pure PET was only about 13 h, whereas plasma-treated PET and the PET/ZnO (100%) composite exhibited significantly extended shelf-lives of approximately 84 and 76 days, respectively. These findings highlight the effectiveness of oxygen plasma in fabricating PET/ZnONP composites and their significant potential for use in advanced food packaging applications.

Cannabis sativa (hemp) is an industrial crop with expanding applications in the agrifood, textile, and pharmaceutical sectors. Despite its economic potential, seed germination and quality, essential for plant development and crop establishment, are suboptimal. In this context, plasma-induced seed priming represents a novel approach to improve germination efficiency. Although these treatments are rapid, their efficacy depends on the careful optimization of several operational parameters. Here, we aimed at developing optimized plasma priming treatments for hemp seeds by evaluating the influence of gas composition, operating pressure, and treatment duration. Two seed lots of a commercial hemp variety with distinct seed quality levels were used. The physiological effects on seed germination were determined by measuring several parameters (germination percentage, rate, and speed) while additional analyses included the levels of water uptake, surface hydrophilicity, chemical modifications, oxidative status, and selected gene expression profiles. Integrative data analysis revealed that oxygen-based plasma applied at high power intensity and short exposure time resulted in enhanced germination performance, likely due to increased hydrophilicity and subsequent water uptake. This treatment likely acted as a priming agent, stimulating pre-germinative metabolism, as evidenced by the transcriptional profiles of target genes. However, prolonged exposure resulted in detrimental effects possibly attributed to an excessive water uptake and ROS over-production. Overall, these findings suggest that properly calibrated plasma treatments can stimulate beneficial physiological responses and enhance germination, whereas excessive exposure disrupts cellular homeostasis and compromises seed performance.

The treatment of dye-contaminated wastewater remains a significant challenge for environmental management due to the high stability and persistence of many azo dyes. The purpose of this study was to develop and evaluate a novel hybrid rotor-stator hydrodynamic cavitation non-thermal plasma device designed to enhance the decolorization of Reactive Red 120. The configuration integrates atmospheric-pressure plasma directly into a cavitating flow field, attempting to increase gas-liquid interfacial contact and promote mass transfer of reactive species into the liquid. The device performance was investigated by assessing the effects of various parameters on H2O2 production, pH, conductivity, and energy consumption. The results show generation of reactive species at all tested parameters, with higher H2O2 production in deionized compared to tap water. Rotational speed, discharge voltage and air flow rate all influenced H2O2 production and the highest concentration achieved was 9.9 mg/L in 15 min. Decolorization was evaluated at three initial concentrations and followed apparent pseudo first-order kinetics, with higher degradation rates observed at lower initial dye concentrations (0.0273, 0.0234 and 0.0168/min at 25, 50 and 100 mg/L, respectively). The study demonstrates that coupling of hydrodynamic cavitation with non-thermal plasma produces synergistic effects and has potential to treat complex wastewaters.

Polyvinyl chloride (PVC) is often the material of choice for the synthesis of various components used in medical practice, particularly catheters. As-synthesized components may not exhibit appropriate biocompatibility, so the surface should be modified or coated. Amine groups were grafted onto the PVC surface by brief exposure to ammonia plasma generated by a low-pressure inductively coupled radiofrequency discharge in E mode (30 Pa, 25 W). The treatment time ranged from 0.5 to 300 s. The measured density of charged particles was approximately 2 +/- 1 x 1015 m- 3 and the flux of NH and NH2 radicals was approximately 3 x 1023 m-2s-1. X-ray photoelectron spectroscopy (XPS) was used to study the evolution of nitrogen-containing functional groups versus the treatment time. The chlorine concentration was not affected much, but the nitrogen concentration in the surface film increased logarithmically with increasing treatment time. The N concentration was approximately 2 at.% after 0.5 s of treatment and reached approximately 9 at.% after 300 s. Some PVC samples were also pretreated with hydrogen plasma. The pretreatment was beneficial for rapid functionalization, as the N concentration reached 6 at.% after 0.5 s of plasma treatment, but the concentration after prolonged treatment was the same as that for a single-step ammonia plasma treatment. High-resolution XPS Cl2p spectra revealed significant modification of the chlorine binding, especially after pretreatment with hydrogen plasma. A possible explanation for this modification is the formation of Cl-binding states, resulting from bond scission by the absorption of VUV radiation in the PVC surface film.

A rapid, nonthermal method for surface decontamination of aflatoxins B1, G1, B2, and G2 was developed using vacuum ultraviolet (VUV) photons emitted from an inductively coupled hydrogen plasma. The plasma, sustained at 18 Pa with input powers between 50 and 700 W, produced intense VUV emission in the 140-160 nm range (photon energy approximate to 8 eV) that was delivered to samples through an MgF2 window with > 80% transmittance. On quartz glass substrates coated with 40 ng of aflatoxin mix (film thickness approximate to 3 nm), VUV photons caused > 90% degradation within 10 s of VUV exposure. When applied to artificially contaminated maize grains (approximate to 20 mu g kg(-)(1) AFB1/G1, 4 mu g kg(-)(1) AFB2/G2), VUV treatment achieved up to 80% toxin removal in under 1 min as measured by HPLC, but the remaining (approximate to 20%) persisted even after 10 min of VUV irradiation, which was explained by the inability of VUV photons to penetrate into micron-scale grooves and crevices on the maize grain surface. These findings demonstrate that hydrogen-plasma VUV radiation can rapidly inactivate surface-bound aflatoxins on smooth substrates and agricultural commodities. However, the restricted penetration depth and vacuum chamber requirements limit bulk-grain scalability. Hybrid approaches combining VUV pretreatment with mechanical agitation and enzymatic degradation may offer a more energy-efficient, scalable solution for decontaminating porous food substrates.

Graphene oxide (GO) is a standard precursor for the synthesis of porous yet densely packed, graphene-like structures in films with a thickness of several micrometers, which are useful for electrodes in various electrochemical devices, such as supercapacitors, as well as for various sensors. As-synthesized GO films exhibit inadequate electrical conductivity because of a large concentration of oxygen chemically bonded to graphene sheets. Heating of GO films in a non-oxidizing atmosphere will cause thermal decomposition of GO by desorption of carbon oxides, which will result in numerous defects in the sheets and partial collapsing of the sheets. An alternative is the treatment of GO films with non-equilibrium hydrogen plasma, which causes reduction rather than decomposition of the GO sheets. The scientific literature on approaches to reducing GO samples by treatment with hydrogen plasma is reviewed, the results are critically evaluated, and the correlations between the reduction efficiency and processing parameters are drawn. Paradoxically, larger discharge powers lead to worse results, both in terms of the remaining oxygen concentration and electrical properties. A feasible explanation for this paradox is radiation damage, which is likely caused by energetic photons or ions. The recommendation for further experiments in this tremendously promising niche is also presented.

The increasing accumulation of plastic waste and the depletion of natural mineral aggregates have driven interest in the use of recycled plastic particles as alternative aggregates in concrete. However, weak interfacial bonding between hydrophobic plastic particles and the cement matrix remains a critical limitation. This study investigates the effect of oxygen plasma surface modification on the mechanical performance of concrete incorporating recycled polypropylene flakes (PPF) and polyethylene agglomerates (PEA). Compressive and flexural strength tests, together with triaxial tests under confined conditions, were performed. Surface wettability was evaluated using contact angle measurements, and interfacial morphology was analysed by scanning electron microscopy (SEM). Although plastic particles reduced compressive strength compared to reference concrete, plasma treatment improved mechanical performance, particularly for PEA mixtures, with compressive strength increasing by up to 33

Current global policies, such as circular economy, electrification, and low carbon footprint dictate the replacement of fossil fuels for synthesizing electrodes of graphene supercapacitors with renewable sources. The traditional method for depositing graphene and similar structures is based on gaseous hydrocarbons. The possibility of replacing them with waste plastic is presented. We used propane and waste plastics (mostly polypropylene) for the deposition of a few & micro;m-thick deposit of carbon nanowalls composed of vertically oriented multilayer graphene-like sheets on electrodes by plasma-enhanced chemical vapor deposition (PECVD). We studied their morphology and structure, as well as the performance of coin-shaped supercapacitors. The graphene-like coatings were deposited in plasma sustained at the pressure of 16 Pa by inductively coupled RF discharge in the H mode at the forward power of 500 W and power density approximately 8x106 W/m3. Such a powerful plasma caused thermal decomposition of the waste plastic. Optical emission spectroscopy showed significant differences only within the first few seconds of plasma treatment, which was enough to supply precursors for graphene growth. Both scanning and transmission electron microscopies showed similar structures for deposits prepared from propane or waste plastic, and the deposition rates of roughly 100 nm/s were observed. Waste plastic enabled the deposition of 2-3 times densely packed multilayer graphene-like sheets of a typical thickness of 5 nm at deposition times over 1 min. Raman spectroscopy indicated a somewhat lower concentration of defects for samples deposited from polypropylene, but the ID/IG versus the average distance between the neighboring multilayer graphene-like sheets followed the same line. The specific capacitance increased steeply with deposition time for deposits prepared from waste plastic and it was found to be linearly dependent on the ratio between the effective and projected areas of both precursors. The capacitance versus the ID/IG followed the same curve for both precursors. The results demonstrate the feasibility of replacing gaseous hydrocarbons with waste plastics for PECVD deposition of graphene electrodes.

Water is essential for life, yet it often contains harmful contaminants and microorganisms that pose risks to human health. Conventional treatment methods such as chlorination, filtration, and UV irradiation remain widely used, but each has limitations related to efficiency across contaminant types, cost, and potential safety concerns. Advanced oxidation processes (AOPs), which generate highly reactive species such as hydroxyl radicals (OH), offer a promising alternative due to their rapid and non-selective reactivity toward organic pollutants.

Gas conversion between hydrogen (H2), nitrogen (N2), and ammonia (NH3) is a scientific topic of interest in both methods for low-temperature synthesis of ammonia and energy-efficient production of hydrogen for powering fuel cells. The efficiency of catalysts for ammonia synthesis at room temperature was evaluated. A mixture of hydrogen and nitrogen with a ratio in a broad range between 1.5:1 and 80:1 was passed through a plasma sustained by inductively coupled radio frequency discharge in the H mode at a power of 700 W and pressures between 40 and 100 Pa. Several catalysts were placed in the flowing afterglow where the H and N densities were of the order of 1021 m-3, and the conversion efficiency (η) was evaluated. The efficiency increased almost linearly with increasing enthalpy of nitride formation. The best results were observed for copper, for which the conversion was almost twice the value in the same system without the catalyst. The efficiency of NH3 production by the conversion of N atoms into NH3 molecules versus the gas mixture exhibited a broad maximum and was as large as η ≈ 29% in the mixture of hydrogen and nitrogen between 3:1 and 10:1.

Polydimethylsiloxane (PDMS) is extensively used across various fields due to its high flexibility, favorable mechanical properties, and optical transparency. When PDMS is filled with magnetic microparticles, it acquires magnetic-field sensitivity, which is useful in applications such as droplet-based microfluidics, liquid transporters/distributors, and soft robot locomotion. In some cases, the composite should exhibit hydrophilic surface properties. The hydrophilization of neat PDMS and a composite material (PDMS filled with 70 wt

The hydrophobic character of rice seeds protects them from quick water adsorption and, thus, premature germination. This property is, however, a drawback in modern agriculture, where rapid and uniform germination represents a high-quality trait. A method for rapid hydrophilization of the Lomello variety of rice is presented. The rice seeds were treated with low-pressure gaseous plasma to tailor the wettability. The treatment of seeds with hulls with oxygen plasma afterglow enabled the super-hydrophilic surface finish within 10 ms. Such extremely fast hydrophilization was attributed to irreversible surface oxidation by neutral oxygen atoms whose flux onto the seeds was approximately 3 x 1023 m-2s-1. Dehulled seeds were made super-hydrophilic by subsequent treatments with hydrogen and oxygen plasma, and the required dose of O atoms was between 2 x 1023 and 6 x 1024 m-2. Larger doses caused a loss of the super-hydrophilicity. Hydrophilization kinetics is proposed and supported by measuring surface wettability, morphology, and composition using various techniques. The hydrophobic recovery of seeds with hulls is marginal within the first few days after plasma treatments, but dehulled seeds lose the super-hydrophilic surface finish within a few minutes after the plasma treatment when stored at ambient conditions.

In bonded NdFeB magnets, the fillers' adhesion in the polymer matrix of composites is often insufficient, necessitating filler wettability modification before mixing with liquid polymers. Inductively coupled radiofrequency oxygen plasma was used to modify the surface wettability of commercial NdFeB flakes. A pronounced minimum in water contact angle (WCA) was observed after approximately 100 ms of treatment in plasma (50 Pa, 500 W). A deeper minimum was observed upon treatment in the flowing afterglow. The flux of oxygen atoms on the NdFeB flakes' surface was similar to 3 & times; 10(23) m(-2) s(-1), and the WCA below 20 degrees was observed after treating the samples in the afterglow for 0.05-0.5 s; corresponding O-atom doses 10(22)-10(23) m(-2). Larger doses caused a gradual loss of hydrophilicity, and an initial WCA of similar to 75 degrees was established after treating the samples in the afterglow for similar to 40 s. This was attributed to the segregation and oxidation of iron on the NdFeB surface. Thorough XPS depth profiling revealed oxidation kinetics. The treatment in the glowing plasma caused a similar evolution, except that hydrophobicity was re-established after 1-s plasma treatment. The segregation of iron on the surface caused the formation of Fe2O3, and the intermediate layer toward the bulk consisted of Nd2O3 dispersed in the Fe matrix.

Aflatoxins are toxic organic substances that are synthesized on the surfaces of seeds, nuts, and similar products by some fungi under elevated humidity. They decompose at temperatures well above 130 °C, so standard heating or autoclaving is an obsolete technique for the degradation of toxins on surfaces without significant modification of the treated material. Non-equilibrium plasma was used to degrade aflatoxins at low temperatures and determine the efficiency of O atoms. A commercial mixture of aflatoxins was deposited on smooth substrates, and the solvent was evaporated so that about a 3 nm thick film of dry toxins remained on the substrates. The samples were exposed to low-pressure oxygen plasma sustained by an inductively coupled radiofrequency (RF) discharge in either the E or H mode. The gas pressure was 20 Pa, the forward RF power was between 50 and 700 W, and the O-atom flux was between 1.2 × 1023 and 1.5 × 1024 m−2 s−1. Plasma treatment caused the rapid degradation of aflatoxins, whose concentration was deduced from the fluorescence signal at 455 nm upon excitation with a monochromatic source at 365 nm. The degradation was faster at higher discharge powers, but the degradation curves fitted well when plotted against the dose of O atoms. The experiments showed that the aflatoxin concentration dropped below the detection limit of the fluorescence probe after receiving the O-atom dose of just above 1025 m−2. This dose was achieved within 10 s of treatment in plasma in the H mode, and approximately a minute when plasma was in the E mode. The method provides a low-temperature solution for the efficient detoxification of agricultural products.

Innovative technological solutions are needed for water decontamination to combat the diverse pollutants present in water systems, as no single optimal decontamination technique is appropriate for all circumstances. Vacuum-ultraviolet (V-UV) radiation is a source of energetic photons that break molecular bonds, producing a plethora of chemically reactive agents, most notably OH center dot radicals, which can cause the degradation of harmful pollutants. Low-pressure gaseous plasma is a good source of V-UV radiation; however, its application to liquid water poses challenges. We constructed an inductively coupled radiofrequency plasma to produce high-intensity V-UV radiation, which was applied to contaminated water via a V-UV-transparent window. Plasma was sustained in hydrogen, as it produces the highest V-UV intensity among all gases at selected discharge parameters. Bacteriophage MS2 was used as an indicator of microbial decontamination efficiency. Reactive oxygen and nitrogen species were measured at various treatment setups to quantify their effect on MS2 inactivation and elucidate the primary inactivation factors. At optimal conditions, the concentration of active virus dropped by 9 log10 PFU/mL in 60 s. The optimal experimental setup was then used to treat bacteria E. coli, S. aureus, antibiotic tetracycline, and synthetic dye methylene blue as representatives of other types of pollutants, all of which were effectively removed/degraded within 10 min of treatment. A comparison of energy efficiency (EEO) to other disinfection setups was made for bacteriophage inactivation. With a low EEO value, we showcase the potential of this technique for further work in this field.

The remarkable properties of fluorinated polymers are the reason for their use in medicine, such as vascular grafts, surgical meshes, or sutures. However, their use as vascular grafts can be accompanied by drawbacks, in particular thrombosis leading to limited patency of the graft in the long term. To reduce thrombosis and protein adsorption, coatings imitating the layers found on the surface of vascular endothelial cells could potentially be used. For any covalent permanent surface functionalization to be possible, otherwise almost inert fluorinated polymers must be activated. For that purpose, a protocol is described in this work that allows for the activation of spin-coated polyvinylidene fluoride (PVDF) thin films with an ammonia plasma, introducing amino groups at the surface. The amino groups can be used to covalently attach N-protected glycine and thus modify the polymer surface via conventional solid phase peptide synthesis. The morphological features of the films are investigated by atomic force microscopy and the hydrophilicity quantified by water contact angle measurements. The chemical composition of the films is characterized by X-ray photoelectron spectroscopy. This work contributes to the understanding of fluoropolymer plasma activation and subsequent grafting of amino acids and, therefore, lays the foundation for a subsequent tuning of PVDF as a medical material.

The increasing promotion of a hydrogen-based economy and the use of low-carbon energy sources is critical to the global drive toward carbon neutrality by 2050, and ammonia is among the most promising intermediate products. The current industrial method for ammonia synthesis is the Haber-Bosch (H-B) process, which requires large amounts of fossil fuels, high temperatures and pressures, significant capital investment, and environmental issues. An alternative research interest focusing on plasma catalysis offers a clean, sustainable, and flexible alternative method to convert nitrogen into active species for ammonia (NH3) synthesis, but the science of ammonia synthesis using plasma technologies is still in its infancy. In the current review, we summarize the roles of catalyst materials and different plasma-excitation methods (i.e., dielectric barrier discharge (DBD), microwave (MW), gliding arc (GA), and radio-frequency (RF)) for plasma-based ammonia synthesis. We discuss the mechanisms of NH3 synthesis in the presence of a plasma with a catalyst under different plasma conditions. We summarize recent developments and the key challenges related to plasma catalytic NH3 synthesis, scaling-up possibilities, economic concepts, and an outlook for the future. Finally, this review aims to provide a detailed overview of the emerging ammonia synthesis technologies developed to effectively store green hydrogen for future applications.

Water disinfection is a critical treatment step for removing harmful organisms from contaminated water sources. Vacuum ultra-violet (V-UV) radiation, generated by a low-pressure gaseous plasma discharge, consists of photons with high enough energy to break molecular bonds. In this work, we constructed and characterized a low-pressure capacitively coupled gaseous plasma and used it as a V-UV radiation source to inactivate MS2 bacteriophage, a surrogate for human enteric viruses. The treatment system allows for variation of gas composition inside the sample chamber and the modulation of V-UV radiation intensity. Both were used to separate the actual germicidal contribution of V-UV radiation from producing germicidal species by using virus inactivation to determine efficiency. OH* radical production was determined through the terephthalic acid chemical probe, which showed that when air was present in the sample chamber, it resulted in the highest OH* production and the best inactivation of MS2. Furthermore, we showcase that the OH* production rate was wavelength dependent and that ozone, generated by plasma treatment in the gas phase, leads to hydroxy terephthalic acid degradation, allowing us to determine better the actual OH* production rate with different treatment regimes. Lastly, by adding an OH* scavenger to the liquid, we were able to elucidate it as the primary inactivation agent in this setup while also providing evidence of its production in the bulk liquid by the transport and subsequent decomposition of the longer-lasting ozone molecule. This study demonstrates, for the first time, the applicability of low-pressure plasma radiation as a water treatment method.

The kinetics of surface recombination of neutral oxygen atoms on nanocarbon deposited on oxidized cobalt catalyst in inductively coupled radiofrequency plasma sustained in propane in the H-mode is presented. The coefficient was measured in the range of temperatures between 300 and 800 K and pressures between 40 and 200 Pa. A deep minimum in the coefficient at 0.03-0.06 was observed and explained by a deposition of a rather smooth carbon film on the cobalt catalyst. Prolonged deposition caused the growth of perpendicularly oriented multilayer graphene sheets with the distance between the neighboring sheets around 100 nm. The large aspect ratio of the gaps, whose depth reached several micrometers after deposition time over 100 s, caused the trapping of oxygen atoms and, thus, numerous collisions with the graphene-like surface, so the coefficient increased for over an order of magnitude. The maximum coefficient over 0.5 was observed at low pressures and elevated temperatures. The evolution of the recombination coefficient was explained by the peculiarities of the binding sites for oxygen atoms on graphene surfaces.

The spatial profile of atomic oxygen in a cylindrical afterglow chamber with a height of 41 cm and an inner diameter of 30 cm was measured. The source of oxygen atoms was a remote microwave plasma operating at a discharge power of about 250 W. The gas flowed through a quartz-glass tube with inner and outer diameters of 3.8 and 6.0 mm, respectively. The exhaust of the quartz tube widened to cones of various geometries. The spatial distribution of atomic oxygen was determined for cones with an outer diameter of up to 40 mm. The tube with the widest cone (Tube 3) provided the largest O-atom density of 6 x 1020 m-3 in the upper part of the afterglow chamber away from the main gas stream in the pressure range from 50-200 Pa, while the tube (Tube 1) with the narrowest cone enabled an O-atom density of up to 2 x 1020 m-3. The differences in measured oxygen density for three tubes at positions 'up' and 'down' decreased with increasing pressure and were below the detection limit at pressures above 350 Pa. In the case of the 'middle' position, Tube 2 with an outer diameter of 19.3 mm exhibited a sharper decrease in oxygen density compared to Tube 1 and Tube 3. The O-atom density in the middle of the afterglow chamber increased with the increase in the percentage of pump valve opening at the lowest probed constant pressure of 40 Pa, but it stayed constant for the opening of the pump valve above 70%. For constant pressures above 100 Pa the O-atom density decreases with the larger pump valve opening. The pressure is kept constant by the corresponding increase in oxygen gas flow while increasing the percentage of the pump valve opening. The spatial profiles are explained by the effects of gas flow and diffusion.