Increasing Carbon Content Research Articles

Superhydrophobic performance of aluminum textured with a picosecond laser

Aluminum is a common and light engineering metal with high strength, good processability, corrosion resistance, high electrical conductivity, and strong recyclability, properties that allow its wide use in different fields. Strengthening the surface properties of aluminum materials can not only enable aluminum materials to be applied to complex environments but also extend their service life. In this study, two kinds of micro–nano structures—unidirectional micro-grooves and grid micro-grooves—were prepared on the surface of 1060 aluminum using picosecond-laser direct etching, so that its surface can attain superhydrophobic properties and enhance its application performance. The effect of the scanning interval of picosecond laser on the hydrophobic performance was investigated, and the findings indicate that the hydrophobic properties are most effective by using scanning interval of 20 μm. The scanning electron microscope (SEM) and atomic force microscope (AFM) analyses revealed the formation of a micro-nano structure resembling nanoflower particles on the laser-treated aluminum surface, which contributed to increased surface roughness. EDS analysis indicated an increase in carbon (C) content, likely due to the adsorption of organic molecules from the air, which further promoted hydrophobicity. X-ray diffraction spectrometry (XRD) and X-ray photoelectron spectroscopy (XPS) provided insights into the surface chemistry and the presence of various elements and compounds. The superhydrophobic aluminum surfaces demonstrated remarkable stability and self-cleaning capabilities, desirable traits for many practical applications. This study provides a simple and rapid method for preparing superhydrophobic materials on aluminum surfaces and has potential practical application value.This innovation paves the way for the development of high-performance aluminum materials suitable for a wide range of environments and uses.

Holocene paleoenvironmental history of Jackson Lake (Grand Teton National Park, USA) deduced from CHIRP seismic reflection and radiocarbon-dated sediment cores

Sedimentary records from Jackson Lake (Grand Teton National Park, Wyoming, USA) provide an opportunity to investigate the Late Quaternary tectonic and hydroclimatic history of a region known to have considerable earthquake hazard potential. Here, we present a new paleoenvironmental reconstruction for Jackson Lake using high-resolution Compressed High-Intensity Radar Pulse (CHIRP) seismic reflection data and sediment cores from Moran Bay, which is adjacent to the active Teton fault on the southwestern lake margin. Three seismic units (SU) are present within Moran Bay. The lowermost SU-1 defines the acoustic basement, which is characterized by a sharp reflector of variable relief above material with a very low signal-to-noise seismic response; direct sampling reveals this unit to be glaciogenic in origin. SU-2 contains diverse acoustic facies that onlap, downlap, and drape underlying strata. Prominent in SU-2 are faulted, folded, and slumped reflections with mixed amplitude characteristics, as well as reflections organized into prograding clinoforms, which suggest a history of deformation and slope instability in fluvio-deltaic and shallow lacustrine environments. A local unconformity separates SU-2 and SU-3, and above this boundary clinoform packages backsteps towards the hinterland. A bi-directionally tapering package of low-moderate amplitude, continuous to semi-continuous reflections onlap the clinoform; this unit was fully cored (13.8 m), allowing the unit boundary to be sampled and dated. Radiocarbon ages indicate that the core spans ca. 10.4 calibrated kiloyears before present (cal ka BP) to present. Retrogradational stacking of deltaic clinoforms are best explained by increased accommodation in Moran Bay around ca. 10 ka, consistent with a major earthquake and hanging wall subsidence on the Teton fault. Two turbidites identified in the strata align temporally (ca. 10.3 ± 0.4 cal ka BP and ca. 8.3 ± 0.3 cal ka BP) with earthquakes on the Teton fault that have been identified in terrestrial and lacustrine paleoseismic records. From ca. 10.4–6.6 cal ka BP core sediments are relatively rich in clay with highly variable magnetic susceptibility and organic carbon content. Deposition during this period was influenced by an evolving stream network and a relatively dry paleoclimate. From ca. 6.6–2.7 cal ka BP core sediments have higher sand and organic carbon contents, suggesting variable fluvial discharge and climate instability. The youngest core records produced a sharp increase in sedimentation rate, sand and organic carbon content, propelled by greater effective moisture, higher lake levels, and increasing watershed vegetation density. Based on clinoform rollover position, water levels at ∼2,046, ∼2,049, ∼2,053, and 2063 m asl characterized Moran Bay during the Holocene. Together, the seismic and core data records indicate a complex and dynamic Holocene lacustrine evolution controlled by fault motion and water level changes.

Effect of different exfoliation routes on the properties of chicken feather and elephant grass hybrid biochar

AbstractLiquid‐phase exfoliation, a technique for enhancing the properties of biochar, has been recognized as effective, circumventing the limitations of other methods such as high expenses, scalability, and complexity. This study explored the synergistic effect achieved by combining chicken feathers with elephant grass to create a composite feedstock for biochar production. The biochar was subjected to liquid‐phase exfoliation using acid and acetone. Elemental analysis indicated that the co‐carbonization of the combined biomass produced an enriched hybrid biochar. The oxygen content in both exfoliation routes (acid and acetone) increased, with an increase and decrease in carbon content in acetone and acid exfoliation, respectively. Textural analysis revealed significant enhancement, with surface areas of the acid‐exfoliated biochar more than twice the size of the hybrid biochar. The pore volume of both exfoliated samples was double that of the hybrid biochar. Microscopic surface examination revealed rougher, porous structures in the exfoliated biochars in comparison with the smooth, cohesive surface in hybrid biochar. Functional group analysis showed the presence of aromatic rings, a carbocyclic group, and an alkene, suggesting potential applications in adsorption. This study provides an efficient method for using liquid‐phase exfoliation to enhance biochar properties, benefiting industries reliant on biochar production and biomass utilization by improving product quality, sustainability, and environmental impact.

Thermocatalytic Pyrolysis of Waste Areca Nut into Renewable Fuel and Value-Added Chemicals.

Pyrolytic oil is currently in its early stages of production and distribution but has the potential to grow into a significant renewable energy source. It may be processed into a variety of useful substances, including chemicals, and used for heating, transportation, and energy production. The present investigation involves the production and characterization of pyrolytic oil from areca nut husk (ANH), with and without ZSM-5. The pyrolysis experiment was conducted in a semibatch tubular reactor at 600 °C and a heating rate of 80 °C min-1 using ZSM-5 at 20 wt %. The pyrolytic oil was examined via elemental analysis, viscosity, density, moisture content, GC-MS, FTIR, higher heating value (HHV), and ash content. The analysis of kinetics verified that the activation energy rises in proportion to the conversion rate. Additionally, employing ZSM-5 in catalytic pyrolysis at 20 wt % boosted the yield of pyrolytic oil by 11% compared to thermal pyrolysis. Employing ZSM-5 at 20 wt % resulted in a decrease in viscosity, oxygen content, and density by approximately 43.40 cSt, 15.20%, and 168 MJ kg-1, respectively. Moreover, it led to an increase in higher heating value (HHV) and carbon content by 11.71 MJ kg1- and 14.06%, respectively. An FTIR study of pyrolytic oil revealed the occurrence of hydrocarbons, aromatics, phenols, alcohols, and oxygenated chemicals. Moreover, GC-MS analysis indicated a significant increase in hydrocarbons (10.31%) and a decrease in phenols (2.36%), acids (6.38%), and oxygenated compounds with the introduction of the catalyst. Consequently, it can be inferred that utilizing ZSM-5 at 20 wt % during the pyrolysis of ANH aids in enhancing both the yield and characteristics of the resulting pyrolysis oil.

Thermal properties and grey correlation degree analysis of tar-rich coal under cryogenic and pyrolysis condition

The thermal properties of coal are important factors that influence the heat and mass transfer during the pyrolysis process. Therefore, thermal properties were investigated for two tar-rich coal under cryogenic temperature and pyrolysis condition using laser flash analyzer. Gray correlation analysis and chemical composition analysis are combined to analyze the impact of chemical properties on thermal properties. With decreasing temperature, the thermal diffusivity of coal experiences a significant increase by 108.9–121.4 %, while the specific heat capacity decreases by 57.9–65.9 %. The volatile matter and fixed carbon content in tar-rich coal have the highest correlation with thermal properties (∼0.9), followed by moisture content (∼0.62), while the ash content has the lowest correlation with thermal properties (∼0.5). The thermal diffusivity of tar-rich coal increases with increasing volatile matter content. Furthermore, within the range of −100 °C to 300 °C, the thermal diffusivity of tar-rich coal decreases with increasing carbon content, while the specific heat capacity increases with increasing carbon content. The results indicate that under low-temperature cryogenic conditions, the internal heat transfer capability of tar-rich coal is significantly improved.

Influence of biodestructors on sequestration of labile carbon compounds in the soil

Ukraine stands as a testament to agricultural wealth due to its fertile soils, most notably, its significant share of the world’s chornozem. Rich soil is fundemantal to agricultural production, and therefore the success of the agricultural industry heavily relies on the fertility of the soil. However, modern agricultural practices in Ukraine, have led to increased anthropogenic impact on soils, affecting their biodiversity and humus content. In this regard, it is becoming increasingly important to perform comprehensive studies of microbiological, biochemical and chemical processes in the soil in response to different agricultural interventions. The urgent need to restore natural ecosystems to preserve their biodiversity and ensure ecological stability poses new scientific challenges, emphasizing the importance of urgent measures aimed at protecting the environment from pollution and degradation. This research aims to explore the effects of biodestructors on the deposition of labile carbon compounds in the soil during long-term consistent corn cultivation. The research was conducted during 2020–2023 within the framework of a stationary field experiment of the scientific research department of the «Druzhba Nova» in Varva village, Chernihiv region. The soil is a typical low-humus chornozem with the experiment focusing on a monoculture corn crop rotation. The DKC 4351 corn hybrid was sown at a density of 82 thousand units per hectare, employing a three-part experiment design: 1) a UAN control at 32–28 l/ha, 2) Ecostern Classic at 2 l/ha combined with UAN 32–28 l/ha, and 3) Ecostern Bacterial at 2 l/ha alongside Ecostern Trichoderma at 1 l/ha and UAN 32–28 l/ha. In the present study, the influence of biodestructors on soil’s agrochemical and microbiological indicators, as well as corn yield was evaluated. In a long-term stationary field experiment conducted on a typical low-humus chornozem, we investigated the influence of microbial preparations — plant residue biodestructors — on the deposition of labile carbon compounds in the soil under continuos corn cultivation. The application of Ecostern Classic and a combination of Ecostern Bacterial + Ecostern Trichoderma biodestructors resulted in an increase of labile carbon content by 0.11% and 0.18%, respectively, compared to the control. The aim of further analysis was to determinate the dynamics of the organic matter transformation coefficient, which is a marker of enhanced microbiological activity in the soil and a predominance of organic matter synthesis over its mineralization. In treatments utilizing biodestructors, this indicator was significantly higher than control values throughout the study. The survival of the fungal bioagent from Ecostern Classic and Ecostern Trichoderma bioproducts in the soil was monitored by assessing the population dynamics of the Trichoderma genus species. Results demonstrated an increase by an average of 19 thousand CFU/g with Ecostern Classic and by 34 thousand CFU/g with the combined use of Ecostern Bacterial with Ecostern Trichoderma, compared to 28 thousand CFU/g in control soil samples. This may indirectly indicate a successful colonization of the bioagent in treated soils. Using BIOTREX technology to evaluate the soil’s ecophysiological diversity, we found that the diversity index increased from 3.66 in control samples to between 4.87 and 5.61 in treatments with biodestructors. According to the further BIOTREX assessment, the use of biodestructors not only increased soil biodiversity, but also improved soil health. The application of these biodestructors also significantly boosted corn grain yield with an increase of 0.32 t/ha with Ecostern Classic treatment and 0.18 t/ha with the combined use of Ecostern Bacterial with Ecostern Trichoderma, compared to control.

Carbon nanostructures supported on Co/serpentinite for sulfentrazone removal

The presence of environmental contaminants is a major problem today. In this context, it is necessary to develop new sustainable materials to be used to remediate these contaminants. In this work, the serpentinite rock was impregnated with cobalt, 5%, 10% and 20% and used as a support for the synthesis of carbon nanostructures by CVD (chemical vapour deposition) process, at 900°C. This temperature was chosen due to the high thermal stability of the carbon source. The materials were characterized by X-ray diffraction, Raman spectroscopy, thermal analysis, scanning and transmission microscopy. As expect the main phases formed were forsterite, Mg2SiO4, graphitic carbon and metallic cobalt. All the synthesis showed the formation of carbon structures as multiwalled carbon nanostructures over cobalt cores. The carbon structures showed good thermal stability, between 470 and 600°C. The higher the cobalt content, the higher the yield of the carbon structures synthesis, i.e. 14%, 23% and 37% for Serp5, Serp10 and Serp20, respectively. The produced materials were used to removal of the environmental contaminant sulfentrazone. After CVD process, the removal of sulfentrazone increase to 17.3%, 18.4% and 25.2% for Serp5, Serp10 and Serp20, respectively, showing an increase in sulfentrazone removal with the increase in carbon content. In addition, the percentage of sulfentrazone removal by Serp20 was greater at acidic pH values, decreasing from 41.7% to 12.7% with an increase from 2 to 10 in pH. The removal capacity obtained experimentally at a sulfentrazone concentration of 50 mg L−1 was equal to 14.9 mg g−1. According to literature and data obtained in this work, it was observed that the removal of contaminants from the aqueous medium occurred through two mechanisms: reduction of the organic compound by Co nanoparticles and adsorption carried out by carbon nanostructures.

Stress-related physiological responses and ultrastructural changes in Hypoxis hemerocallidea leaves exposed to cadmium and aluminium

Hypoxis hemerocallidea is a medicinal plant containing hypoxoside (a pharmacologically active phytosterol diglucoside). This study evaluated the elemental composition in leaves of H. hemerocallidea treated with cadmium (Cd) and aluminium (Al) using scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX). The impact of Cd and Al on photosynthetic pigments and performance, antioxidant activities and ultrastructure were also assessed. Corms of H. hemerocallidea were micropropagated, rooted and then exposed to varying concentrations of Cd, Al, and Cd + Al for six weeks. The SEM/EDX analysis indicated a two-fold increase in carbon content across all treated plants compared to the control. No/little Cd was detected in the leaves compared to a progressive increase in Al concentration with increasing Al treatment levels. This indicted that Al is more readily translocated to the shoots compared to Cd. Plants treated with Cd exhibited a significant decrease in total chlorophyll content accompanied by reduced photosynthetic performance and lower relative electron transport rates. Cd and Al exposure led to higher carotenoid, superoxide dismutase and malondialdehyde levels, indicating oxidative stress. Cd-treated plants displayed increased amylase activity and decreased carbohydrates content. Ultrastructural alterations occurred with exposure to Cd and Al, including abnormal swelling or disintegration of chloroplasts and thylakoid degeneration. An increase in starch grains and a decrease in plastoglobuli were also noted. In conclusion, this investigation provides evidence that both Cd and higher concentrations of Al exert detrimental effects on the ultrastructure, metabolism and photosynthetic performance of H. hemerocallidea, contributing to reduced growth and biological activity when stressed.

Microwave absorption, thermal and mechanical properties of amorphous nano carbon doped aluminium nitride composite ceramics

Low-cost amorphous nano-carbon (ANC) was employed as an absorbent to modify the microwave performance of AlN ceramics (AlN-4 wt% Y2O3-x wt% C, x = 0, 2.0, 3.8, 3.9, 4.0) via hot-pressing sintering, and the thermal and mechanical properties were also investigated. With the increase of ANC content from 0 to 4.0 wt%, the relative density of AlN composite decreases from 3.28 g cm−3 to 3.16 g cm−3 when sintered at 1800 °C for 2 h, and with the increase of sintering temperature from 1700 °C, the density of the 4.0 wt% ANC doped AlN composite presents trend of increase and reaches the maximum value of 3.16 g cm−3 at 1800 °C and then decreases. The XRD pattern shows that the composites are composed of AlN and Y–Al–O (YAG, YAP, YAM et al.) phases. SEM results indicate that average grain sizes for AlN and secondary phases gradually decrease with increasing carbon content, suggesting inhibited grain growth due to ANC addition. No obvious changes in phase constitution nor intensity changes were detected with the increase in carbon content and sintering temperature. As the carbon content increases from 0 to 4.0 wt%, the dielectric constant gradually increases from ∼9 to 13.89 at 10 GHz, the dielectric loss gradually increases from the vicinity of 10−3 to 0.38 at 10 GHz, and the reflective loss decreases from −27.92 dB to −49.40 dB, the thermal conductivity of the AlN-ANC composite decreases from 116.63 W m−1 K−1 to 50.13 W m−1 K−1. In addition, with 4.0 wt% ANC addition, the dielectric constant, dielectric loss, reflective loss, hardness, elastic modulus, bending strength, and fracture toughness are 13.89, 0.38, 49.40 dB, 6.4 ± 0.4 GPa, 262 GPa, 268.78 MPa, and 1.4 ± 0.1 MPa m1/2, respectively. Its ability to efficiently absorb microwave energy enhances the performance of devices including radar systems, communication equipment, and microwave heating systems, making it a promising candidate for microwave vacuum electronic applications.

Structural, electronic, and optical properties of 6H-SiC layers synthesized by implantation of carbon ions into silicon

Systematic studies of the gradual fabrication by means of carbon ion-implantation of high-quality 6H-SiC layers on silicon surfaces have been carried out. The fluence of carbon ions varied from 5 × 1015 cm−2 to 1017 cm−2. Results of first-principle calculations, X-ray diffraction (XRD), and Raman spectroscopy demonstrate the amorphization of silicon substrate without any tendency to the segregation of carbon in the samples synthesized at low fluencies. The formation of a SiO2-like structure at this stage was also detected. X-ray photoelectron spectroscopy (XPS), XRD, and Raman spectroscopy demonstrate that an increase in carbon content at 1017 cm−2 fluence leads to the growth of 6H-SiC films on the surface of the amorphous silicon substrate. Atomic force microscopy (AFM) data obtained also demonstrates the decreasing of surface roughens after the formation of SiC film. XPS and Raman spectra suggest that excessive carbon content leaves the SiC matrix via the formation of an insignificant amount of partially oxidized carbon nanostructures. Optical measurements also support the claim of high-quality 6H-SiC film formation in the samples synthesized at 1017 cm−2 fluence and demonstrate the absence of any detectable contribution of nanostructures formed from excessive carbon on the optical properties of the material under study.

Mechanisms of microstructural evolution in high-volume TiC reinforced steel composites: Insights into particle coarsening, morphology, and thermochemical reactions

Titanium carbides reinforced steel matrix (TiC-steel) composites exhibit a range of excellent properties, including increased strength-to-weight ratio, high-temperature strength, and outstanding wear resistance. Prior research has demonstrated that the mechanical properties of TiC-steel composites are significantly affected by particle coarsening and the associated core-rim structure. Nevertheless, the fundamental mechanisms of thermochemical reactions that govern the formation of the final microstructure in these composites, including the core-rim structure, remain incompletely explored. This study elucidates the microstructure evolution mechanism of high-volume TiC-steel composites, particularly particle coarsening, through thermodynamic calculations and chemical analysis. The investigation unveils the coarsening process, shedding light on the formation of more stable phases and associated compositional changes, including the incorporation of substitutional elements and carbon depletion (resulting in low stoichiometry, x < 1) within the newly developed (Ti,M)Cx. Additionally, the increased carbon content contributes to pearlite emergence within the steel matrix. Notably, key factors influencing the distinct morphologies observed in growing TiC particles are identified, attributed to variations in Mo, V, and W concentrations, as elucidated by rigorous thermodynamic and first-principles calculations. This study represents significant progress in understanding the intricate microstructure development of high-volume TiC-steel composites.

Effects of banqueting on water infiltration and physico-chemical properties of soil in semi-arid lands

Banqueting is a simple and cheap soil conservation practice in natural rangelands under dry climates. Little research exists about its impacts compared to other land uses, where agriculture and land abandonment may be important reasons for degradation. This study has evaluated water infiltration and key physico-chemical properties of soil in natural rangelands with banquets in West Azerbaijan (North-Western Iran) compared to: (i) undisturbed sites (assumed as reference condition) and (ii) cultivated or abandoned dry farmlands. Under these soil conditions, the texture, bulk density, porosity, water content, pH, electrical conductivity, organic carbon and carbonate contents of soil (using common physical-chemical methods) as well as the hydraulic conductivity (using a single-cylinder infiltrometer) were measured in the topsoil (0–20 cm). This data was further processed by applying the Principal Component Analysis and the Agglomerative Hierarchical Cluster Analysis. In areas with banquets, soil hydraulic conductivity was higher by 84% compared to dry farmlands (abandoned or not), where water infiltration was noticeably reduced (−44%) compared to the reference soil condition. Moreover, a noticeable increase in organic carbon content (+80%) and a lower salinity (−36%) of soil compared to cultivated areas was measured. These effects are important to enhance soil fertility on one side, and resistance to erosion on the other side. Therefore, in the experimental areas, banqueting may counteract the degradation of soil due to the agricultural activity as well as its abandonment, and restore the properties of the undisturbed soils that are typical of natural rangelands. The results of this study may be of help for landscape managers and agronomists for the pressing needs for soil conservation and productivity in semi-arid areas that are prone to degradation and abandonment.

Trade flows, carbon leakage, and the EU Emissions Trading System

The EU Emission Trading System (EU ETS) has been shown to have reduced emissions in the participating countries and industries since its adoption in 2005. However, there is less evidence on the shifting of production outside EU to avoid emission controls. We study this so-called carbon leakage with gravity analysis of international trade flows and carbon intensities of trade. We utilize the gravity model on a sectoral level and study its implications empirically. Our findings with new OECD data indicate that some carbon leakage has in fact occurred due to the EU ETS, resulting in higher carbon content of imports to the EU. At the same time, we show that the EU ETS has induced lower carbon content of exports from the EU. In further analysis, we show that the carbon leakage we find has caused a moderate increase in total carbon content embodied in the EU’s trade, despite the decreases in exported carbon.

Removal of heavy metal ions from industrial (mining) wastewater using electromagnetically activated carbonaceous sorbent

Mining wastewater, characterized by elevated salt levels, necessitates effective treatment to prevent contamination of underground and surface water. Traditional methods for treating large volumes of mining wastewater with high total dissolved solids are expensive, and cost-effective alternatives are limited. In this study, we propose a solution to this challenge: the sorption of dissolved substances using a carbonaceous sorbent derived from waste, specifically rice husk biochar. To enhance the sorbent’s efficiency, we subjected it to electromagnetic activation, resulting in increased carbon content (from 43.3 to 78.5 % compared to the initial biochar), reduced impurities, and particle size reduction to the nanoscale (1–50 nm) with the formation of mesopores (mean diameter from the adsorption isotherm is 167 Å) and micropores (4.92 Å). This process contributes to improved compositional homogeneity. The effectiveness of the proposed sorbent was validated through the treatment of wastewater from Kirov Mine (Novoshakhtinsk, Rostov Region) under laboratory conditions. The removal rates for dissolved heavy metal ions (iron, zinc, manganese) were found to be 89, 84 and 26 %, respectively. A recommended two-stage sorption treatment involves: (1) static sorption using electromagnetically treated rice husk biochar at a concentration of 0.5 g/dm3; (2) subsequent reagent treatment of the suspension (SKiF-180 reagent, 1.0 mg/dm3), addition of potassium permanganate for manganese removal, settling for 30 min, and non-pressure filtration with a rice husk biochar filter.

Molecular dynamics simulation of shock waves in Fe and Fe–C: Influence of system characteristics

Pressure-induced phase transformation in iron and its alloys is a classic research topic in solid-state physics, material science, and geophysics. The crystal structure of iron undergoes a phase transformation at a hydrostatic pressure of 13 GPa, changing from a body-centered cubic system to a hexagonal close-packed system. Although extensive research has been carried out on the transformation in iron by using molecular dynamics simulations, there is very limited literature that focuses on the contribution of parent phase orientations, system size, and impurities to the phase evolution. In this work, classic molecular dynamics simulations have been employed to investigate the effects of system size, lattice orientation, and impurity concentration on the pressure-induced phase transformation of iron and iron alloys for the first time. Our results show that the lattice orientation has a strong influence on the phase transition behavior, while the influence of carbon is small. The phase transition is slightly delayed with increasing carbon content, whereas the transition pressure increases from [001] to [011] to [111] orientation. The amount of twinning and stacking faults highly depends on the orientation. It is easiest for solitary waves to travel through [111] lattice orientation. The addition of carbon has a slow-down effect on shock velocities, and this effect increases with carbon content and lattice orientation of the samples from [001] to [011] to [111].

Functionalization of PTFE substrates with quaternary ammonium groups – An approach towards anion conducting properties

Hydrogen produced by electrolysis using renewable energy sources offers a zero-emission alternative to fossil-based sources providing high efficiencies in all energy sectors. Anion Exchange Membrane Water Electrolysis (AEM-WE) combines the advantages of the established technologies, alkaline (AEL) and proton exchange membrane (PEM) water electrolysis. However, AEM-WE still requires optimization, especially with regard to the membrane, catalysts and electrode structure. In this contribution we focus on the improvement of PTFE-based binders for AEM-WE membranes, which provide high chemical stability but lack the required ion conductivity. Thus, the functionalization of PTFE towards quaternary ammonium moieties (QAS) was investigated employing two approaches: (i) NH3-plasma treatment and (ii) O2-plasma with subsequent coupling of aminosilanes. Finally, the surface coupled amino groups were converted into QAS via alkylation with iodomethane (CH3-I), introducing ion conductivity. Successful functionalization was proved by X-ray photoelectron spectroscopy (XPS), displaying changes in the surface composition of PTFE surfaces such as the introduction of amino groups at the expense of fluorine, and the increase in surface carbon content upon alkylation. Furthermore, contact angle measurements revealed increased wettability with water due to the introduction of the polar surface functionalities, while zeta potential measurements confirmed the increase of positive surface charges along the modification processes.

Conversion of CO2 into fibrous carbon materials using Ga-based liquid alloys

This study investigates the catalytic reduction of CO2 using various ratios of Ga-based liquid alloys under different conditions. We explored the alloying of liquid gallium with metals like indium (In) and magnesium (Mg) through mechanical stirring and heating. The alloys, once prepared, were exposed to CO2 in a reactor, with the Ga-In-Mg alloy demonstrating optimal reaction effects. In an exemplary synthesis, 1 g of Ga was combined with 30 wt% In and 7 wt% Mg, yielding a 7 wt% Ga-In-Mg alloy. This alloy, when reacted with CO2 for 10 h, exhibited a maximum weight gain of 445 mg. Elemental analysis showed a carbon content increase from 4.56 % to 72.56 % post-reaction. The reacted alloy, post-acid washing and electron microscopy examination, revealed the production of fibrous carbon materials approximately 7 μm wide. The primary objectives of this research were to identify the optimal temperature for CO2 reduction by the alloy and to determine the most efficient alloy catalyst using orthogonal experimental methods. Furthermore, we aimed to elucidate the catalytic mechanism of gallium-based liquid metal in CO2 reduction. The study also involved analyzing the adsorption and reaction processes by fitting the adsorption and reaction kinetic curves of the liquid metal with CO2. Achieving these objectives could enable the conversion of CO2 into solid carbon products, aligning with current environmental and sustainable development goals. This research offers new insights and innovative approaches to tackling energy-related challenges, highlighting the potential of liquid metal alloys in carbon capture and reduction applications.

Addition of Biochar and Fertiliser Drives Changes in Soil Organic Matter and Humic Substance Content in Haplic Luvisol

Humic substances (HSs) constitute a primary component of soil organic matter (SOM) and play a crucial role in soil formation and fertility. However, comprehensive information regarding quantitative and qualitative changes in HS following biochar’s application to soil still needs to be improved. This study reports on the impact of biochar application at rates of 0, 10, and 20 t ha⁻1 (B0, B10, B20), both with and without nitrogen fertilisation at varying levels (N0, N1, N2), on SOM and HS contents throughout the cropping seasons between 2014 and 2019. The findings reveal changes in SOM and HS contents due to biochar addition and fertilisation. Notably, the most substantial increase in soil organic carbon content was observed in the B20N1 and B10N1 treatments, in stark contrast with the reference B0N0 treatment. A decrease in humification of SOM was noted across all treatments involving biochar, whether alone or combined with different N fertilisation levels. An interesting positive change in HS contents was observed in B10N2, where an increase in humic acids and a decrease in fulvic acids enhanced HS stability and improved HS quality. These findings shed light on the intricate dynamics of SOM and HSs in response to biochar application and nitrogen fertilisation over multiple vegetation seasons of crops on loamy Haplic Luvisols in Central Europe.

АНАЛІТИЧНІ ДОСЛІДЖЕННЯ ЗМІНИ КИНЕТИКИ ФАЗОВИХ ПЕРЕТВОРЕНЬ В СТАЛІ ЗАЛЕЖНО ВІД ХІМІЧНОГО СКЛАДУ

Based on research in recent years, it is known that the strength of pearlite rail steels has reached its limit. In addition, the increase in carbon content has a negative effect on the impact strength and weldability of rail materials. Therefore, there is a need to develop and use new steels with the formation of a structural component of bainite. Determination of the influence of basic chemical elements through the known TTT diagrams and the actual chemical composition on the formation of the structure with the subsequent construction of SST diagrams. The simulation results showed that when the CAD model of chemical compositions is heated at a rate of 30°С/min in steel, the polymorphic a→y transformation begins at a temperature of ~771°С (Ас1) and ends at ~829°С (Ас3). To build the SST, the CAD model was set to a temperature from which cooling to a temperature of 900°C was simulated.

Thermoluminescence and optically stimulated luminescence of α-Al2O3 with different carbon concentrations

Carbon-doped α-Al2O3 (α-Al2O3:C) single crystals (nominal carbon concentrations with 500, 1000, 1500 and 2000 ppm) were grown by the vertical gradient freezing (VGF) method. Thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of as-grown α-Al2O3:C crystals were studied. F and F+ center absorption (except for the sample with 500-ppm carbon) at 205 and 256 nm was enhanced with increasing carbon concentration. The results show that TL and OSL intensities from α-Al2O3:C are strongly correlated with the ratio of absorption coefficients from the F-center to the F + -center. Both TL and OSL intensities of the sample doped with 1000 ppm reach maximum when the ratio of absorption coefficients from the F-center to F + -center is at its highest. The OSL response of the sample doped with 1000 ppm carbon is 3.43 times that of the sample doped with 500 ppm carbon and is 2.47 times higher than that of the TLD-500 K. The activation energies for samples with 500, 1000, 1500 and 2000 ppm carbon were calculated as 1.33 ± 0.11, 1.58 ± 0.02, 1.52 ± 0.02 and 1.52 ± 0.04 eV, respectively. The OSL intensities from α-Al2O3:C appear strongly correlated with the ratio of absorption coefficients F-center to F + -center. These attractive features may pave the way for the VGF method to improve the luminescence and dosimetry properties.