Glass fiber-reinforced plastics (GFRPs) rely on strong fiber–matrix adhesion to achieve optimal mechanical performance. However, conventional sizing systems provide only partial surface coverage and may limit interfacial bonding. The current study investigates atmospheric-pressure plasma-enhanced chemical vapor deposition (APECVD) as an alternative approach for depositing adhesion-promoting plasma coatings on glass fibers intended for epoxy-based composites. Organosilane precursors were deposited using an atmospheric plasma jet under different operating conditions, and the chemical composition and the morphology of the resulting plasma coatings were extensively characterized. Adhesion performance was evaluated by pull-off tests on glass sheets and pull-out tests on glass fibers embedded in epoxy resin. Results show that the plasma coatings provide complete surface coverage and present a tunable chemistry containing several adhesion-promoting functional groups, including silanol and amine-containing species. Pull-off tests on glass sheets demonstrate adhesion improvements of at least 68% compared with untreated glass. In pull-out tests, plasma-coated glass fibers achieved interfacial shear strengths up to 102.9% higher than untreated fibers and 24.4% higher than an industrial reference material. These results demonstrate how atmospheric plasma polymerization can produce effective adhesion-promoting coatings on glass surfaces, thus offering a promising and industrially scalable alternative to conventional adhesion promoters for epoxy-based GFRPs.

With rising CO2 levels and climate change, finding alternatives to fossil fuels is essential. One attractive option is converting CO2 into CO and O-2 via an atmospheric microwave plasma process. This study evaluates conversion and energy efficiency by increasing microwave power and CO2 flow. Power and CO2 flow were varied, with conversion measured using Fourier transform-infrared spectroscopy, mass spectrometry, and gas analysis. A maximum conversion of 21.1 % was achieved at a specific energy input of 1.1 eV molecule(-1), highlighting the potential of this approach for efficient CO2 utilization.

Atmospheric pressure plasma depositions processes are becoming widely implemented in in-line, large-scale industrial application. In the present study, thin films coatings have been deposited by a non-equilibrium atmospheric pressure plasma jet operating on air and organosilane precursors, with the aim of an in-line integration in the industrial production of glass fibers. The characterization of the plasma source, of the resulting thin films, and of the exhaust gases has been carried out over a wide range of operating parameters. Results show a complex dependence on the experimental parameters, including the torch-substrate distance, the plasma operating parameters and the precursor injection management. Cold gas numerical simulations of the plasma jet in an open-air configuration and inside a reactor chamber for industrial production have been carried out and successfully benchmarked with the experimental counterparts. Conclusion drawn from them allowed for a strong reduction in number of necessary plasma torches, while at the same time maintaining a homogeneous coverage of the glass fibers. A second iteration of the reactor chamber, with a halved volume and a better management of the exhaust gas, was made possible on the basis of said simulations, showing promising possibilities for the incorporation into an in-line industrial setup for the high-speed treatment of glass fibers, and consequent improvements in the resulting fibers' surface properties.

Microwave interferometry is a reliable, well established, and non-perturbing method to measure the line-integrated electron density of a non-uniform plasma through the phase shift of a wave that propagates the plasma medium. In this paper we combine the phase shift and the attenuation of the wave to experimentally extract both, the line-integrated density and the electron-neutral collision frequency of an atmospheric plasma torch. In addition, a novel method to obtain the 2D spatial plasma density profile of the torch is demonstrated by measuring the microwave power, without any information of the phase. The receiving antenna of the interferometer is moved perpendicularly to the axis of the torch and measures the spatial distribution of the microwave power. The wave is scattered by the plasma and the scattering profile depends on the plasma density profile. Direct comparison of this scattering profile with 3D full-wave simulations provides information on the electron number density profile of the plasma torch.

In order to reduce the use and combustion of fossil raw materials, increasing reliance must be placed on renewable energies. Many strategies are currently being researched to enable the use of electrical energy from renewable resources for chemical synthesis [1, 2]. This contribution shows the possibility of obtaining basic chemicals by conversion using microwave plasma technology. A challenge for renewable energies, in addition to the storage problem, is the dependence on weather conditions. The plasma technology approach provides excellent flexibility in controlling of the process and thus in utilizing the fluctuating availability of cost‐effective renewable energies. This enables efficient and on‐demand operation.

The tendency of mixed ionic electronic conducting (MIEC) materials to be highly selective towards oxygen allows for their use as oxygen transport membranes (OTMs). To be used as OTMs in plasma assisted CO2 conversion and H2 utilisation applications, requires high oxygen permeability, structural stability against reducing atmospheres (such as CO2, CO, H2, etc.) and suitable mechanical properties. La0.6Ca0.4Co1–xFexO3–d (LCCF) has already shown excellent tolerance against CO2 and recently, in our previous work, its specific variant, La0.6Ca0.4Co0.2Fe0.8O3–d (LCCF_6428) showcased hydrogen tolerance for upto 25 hours at 600 °C. In this work, we aim to further improve the hydrogen tolerance of LCCF_6428 by the introduction of strong Mn4+-O bonds into the material structure. To achieve this, 10 % Fe was substituted with manganese (Mn) at the B site of LCCF_6428. The resulting composition La0.6Ca0.4Co0.2Fe0.7Mn0.1O3–d (LCCF_64271) was chosen and synthesized with ultrasonic spray synthesis (USS). The presence of strong Mn4+-O bonds led to a two-fold increase in the hydrogen tolerance of the membrane material with respect to LCCF_6428 with a slight 5 % decrease in oxygen permeability.

In order to achieve climate neutrality, preferably accompanied by cost reduction, plasmochemical processes open up attractive alternatives for the currently very energy‐intensive production of fertilizers. They can be cheaper, more environmentally friendly and agiler than the current state‐of‐the‐art for fixation of nitrogen building blocks. NO x can be obtained from atmospheric nitrogen in an air‐powered plasma torch operating in‐loco and on‐demand, currently yielding a maximum NO x concentration of 2.8 %. The torch can be further improved in efficiency and is designed for an easy upscaling.

In this study, a recycling approach was adapted for the hydrogen tolerant La0.6Ca0.4Co0.2Fe0.8O3-d (LCCF_6428) oxygen transport membranes that have great potential in plasma-assisted CO2 conversion techniques for producing industrial fuels such as methanol. The major focus was the incorporation of sustainability measures such as integrating life cycle assessment (LCA) into the materials development at an early stage to study and compare the environmental feasibility of the recycled membrane with the primary membrane. The aim was also to ensure reduced resource depletion of critical raw materials such as cobalt and lanthanum by means of recycling. It consisted of microwave-assisted dissolution of the membrane followed by ultrasonic spray synthesis. The recycled membrane exhibited at least 83 % of the oxygen permeability of the primary membrane and maintained hydrogen tolerance up to 600 degrees C for 25 h which is a remarkable result for LCCF_6428 in terms of potentially enhancing its life span. As per the LCA, recycling did result in lower resource depletion. However, the recycled LCCF had a higher overall environmental impact compared to the primary LCCF, mainly due to increased electricity consumption during recycling. These results accentuate the need for a transition towards more efficient processes accompanied by cleaner and renewable sources of energy and critically indicate integration of LCA into materials development to establish the sustainability profile of materials.

La0.6Ca0.4Co1–xFexO3–d in its various compositions has proven to be an excellent CO2-resistant oxygen transport membrane that can be used in plasma-assisted CO2 conversion. With the goal of incorporating green hydrogen into the CO2 conversion process, this work takes a step further by investigating the compatibility of La0.6Ca0.4Co1–xFexO3–d membranes with hydrogen fed into the plasma. This will enable plasma-assisted conversion of the carbon monoxide produced in the CO2 reduction process into green fuels, like methanol. This requires the La0.6Ca0.4Co1–xFexO3–d membranes to be tolerant towards reducing conditions of hydrogen. The hydrogen tolerance of La0.6Ca0.4Co1–xFexO3–d (x = 0.8) was studied in detail. A faster and resource-efficient route based on ultrasonic spray synthesis was developed to synthesise the La0.6Ca0.4Co0.2Fe0.8O3–d membranes. The La0.6Ca0.4Co0.2Fe0.8O3–d membrane developed using ultrasonic spray synthesis showed similar performance in terms of its oxygen permeation when compared with the ones synthesised with conventional techniques, such as co-precipitation, sol–gel, etc., despite using 30% less cobalt.

Experimental findings to contribute to the preliminary design of a metal foil pump for fuel separation in the Direct Internal Recycling loop of the DEMO fusion device are presented. In parametric studies on a small-scale superpermeation experiment with a microwave plasma source and two different metal foil materials, niobium Nb and vanadium V, a substantial increase in permeation with plasma power and with a decrease in pressure was observed. To ease operation in the typical fusion environment, in-situ heating procedures were developed to recover from impurity contamination. The temperature independence of plasma-driven permeation from 600 to 900 °C metal foil temperature was demonstrated. No proof of an isotopic effect for plasma-driven permeation of protium and deuterium could be found. The highest repeatable permeation flux achieved was 6.7 Pa∙m3/(m2∙s) or ~5.5 × 10−3 mol H/(m2∙s). The found compression ratios do safely allow the operation of the metal foil pump using ejector pumps as backing stages for the permeate. In a dedicated experimental setup, the operation of the plasma source in a strong magnetic field was tested. Parametric studies of pressure, power input, magnetic flux density, field gradient and field angle are presented.

The removal of oxygen from the effluent of a CO2 plasma using multiple perovskite La0.6Ca0.4Co0.5Fe0.5 O3-delta hollow fiber membranes is reported. A microwave plasma torch featuring a water-cooled 5 mm nozzle operated at quasi-atmospheric pressure was used. This configuration yielded moderate CO2 conversions (>= 20%) and sufficiently large temperatures to thermally activate up to 21 membranes distributed over various rows in the plasma effluent. The CO2 conversion was only slightly affected by the microwave power and remained unchanged, regardless of the number of membranes placed in the effluent. The amount of permeated oxygen increased both with the microwave power and with the number of membranes, since the former yields hotter effluents (>700 degrees C) and the latter increases the surface area available for permeation. The largest O-2 permeation flow was obtained for 21 membranes and a microwave power of 2550 W: similar or equal to 42 sccm or similar or equal to 4.8% of the available O-2. These correspond to the highest performances of such a plasma-membrane reactor thus far. The permeated O-2 flow was also affected by the argon flow purging the membranes. Using one membrane, the flow of extracted oxygen decreased for an Ar flow below 250 sccm, while the opposite was observed with 10 membranes, yielding an increase in the oxygen flow from similar or equal to 25 to similar or equal to 28 sccm upon decreasing the total Ar flow below 2500 sccm. Key aspects that must be tackled for the design and testing of a plasma-membrane prototype that aims to remove O-2 beyond 90% are discussed.

The chemical industry must become carbon neutral by 2050, meaning that process-, energy-, and product-related CO2 emissions from fossil sources are completely suppressed. This goal can only be reached by using renewable energy, secondary raw materials, or CO2 as a carbon source. The latter can be done indirectly through the bioeconomy or directly by utilizing CO2 from air or biogenic sources (integrated biorefinery). Until 2030, CO2 waste from fossil-based processes can be utilized to curb fossil CO2 emissions and reach the turning point of global fossil CO2 emissions. A technology mix consisting of recycling technologies, white biotechnology, and carbon capture and utilization (CCU) technologies is needed to achieve the goal of carbon neutrality. In this context, CHEMampere contributes to the goal of carbon neutrality with electricity-based CCU technologies producing green chemicals from CO2, N-2, O-2, and H2O in a decentralized manner. This is an alternative to the e-Refinery concept, which needs huge capacities of water electrolysis for a centralized CO2 conversion with green hydrogen, whose demand is expected to rise dramatically due to the decarbonization of the energy sector, which would cause a conflict of use between chemistry and energy. Here, CHEMampere's core reactor technologies, that is, electrolyzers, plasma reactors, and ohmic resistance heating of catalysts, are described, and their technical maturity is evaluated for the CHEMampere platform chemicals NH3, NOx, O-3, H2O2, H-2, CO, and CxHyOz products such as formic acid or methanol. Downstream processing of these chemicals is also addressed by CHEMampere, but it is not discussed here.

In a 2.45 GHz plasma torch, carbon dioxide (CO2) has been converted into carbon monoxide (CO) and oxygen (O-2) at atmospheric pressure. The conversion and the efficiency of the plasma have been determined using two independent measuring methods: mass spectrometry and Fourier transform infrared absorption spectroscopy. The conversion depends on the measurement position in the exhaust gas duct. The conversion values at the beginning of the exhaust gas duct are significantly higher (maximum conversion is 22 %) than in the thermalized state at the end of the duct. In the cold, thermalized state of the gas, the maximum conversion rate is 8 % at 1.5 eV molecule(-1). The maximum efficiency of 25 % is achieved at approximatively 0.6 eV molecule(-1) operating at a microwave power of 0.48 kW and a mass flow of 12 slm CO2.

AbstractUm das Energiesystem nachhaltig zu machen, ist mehr erneuerbarer elektrischer Strom nötig. Er muss zudem für bislang stromentkoppelte Energiesektoren technisch nutzbar werden. Dementsprechend gibt es immer mehr Verfahren, die elektrische Energie in andere Energieformen umwandeln. Beispiele sind Hochtemperatur‐Ko‐Elektrolyse, Plasmaprozesse zur Aktivierung von H2O und CO2 sowie daran anschließende Synthesen von CH‐basierten Energieträgern.

CHEMampere : Technologies for sustainable chemical production with renewable electricity and CO 2 , N 2 , O 2 , and H 2 O

A combined system of a biotrickling filter and a non-thermal plasma (NTP) in a downstream airflow was operated for 1220 days for treatment of emissions of styrene and secondary emissions of germs formed in the biological process. The biotrickling filter was operated at variable inlet concentrations, empty bed residence times (EBRT), type and dosage of fertilizers, irrigation densities, and starvation periods, while dielectric barrier discharge and corona discharge were operated at different specific input energy levels to achieve optimal conditions. Under these conditions, efficiencies in the removal of volatile organic compounds (VOCs), germs and styrene of 96–98%, 1–4 log units and 24.7–50.1 g C m−3 h−1 were achieved, respectively. Fluid simulations of the NTP and a germ emission-based clocking of the discharge reveal further energy saving potentials of more than 90%. The aim of an energy-efficient elimination of VOCs through a biotrickling filter and of secondary germ emissions by a NTP stage in a downstream airflow for potential re-use of purified waste gas as process gas for industrial application was successfully accomplished.

Plasma-based technologies providing extremely flexible 'turnkey' applications are increasingly attracting interest in renewable energy usage and CO2 conversion into carbon neutral fuels. Here, we report a breakthrough concept combining plasma and mixed ionic-electronic conductor hollow fiber membranes for significantly enhancing the oxygen permeability which may stimulate the CO2 conversion by product separation. Structure and composition of La0.6Ca0.4Co0.5Fe0.5O3-delta (LCCF) hollow fiber membranes were characterized before and after oxygen permeation tests in a CO2 plasma. The oxygen permeation flux can be increased by one order of magnitude via this new plasma-assisted hollow fiber membrane concept, reaching up to 4 ml min(-1) cm(-2) in a CO2 containing atmosphere. Long-term operation did not lead to an apparent decrease of the oxygen permeation flux even with fast heating and cooling cycles by switching the plasma repeatedly on and off. Thus, we consider this plasma-assisted hollow fiber membrane concept a promising process for flexible and economical CO(2 )conversion.

DEMO requires a novel fuel cycle architecture with Direct Internal Recycling in order to drastically minimize the tritium inventory. One central element of this architecture is the separation (and compression) of hydrogenic gas from the exhaust gas stream, close to the divertor, which can immediately be recycled to feed the matter injection systems. The hydrogen-selective separation will be achieved by the metal foil pump, a novel pump type relying on the effect of superpermeation, which is a first-of-its-kind application for the conditions to be matched for DEMO. To achieve a convincing performance, each hydrogen particle has to undergo successfully a series of processes before it is separated and pumped. To support the design of such a pump, a comprehensive R&D programme has been started which is currently being focused on (i) the plasma source, (ii) the transport of the suprathermal hydrogen, and (iii) the material and surface aspects of the foil. The experimental and modelling tools are described, examples of recent results are presented and a first prediction on the performance is derived.