Aluminum Content Research Articles

Synergetic effects of Al addition on the performance of CoFe2O4 catalyst for hydrogen production and filamentous carbon formation from direct cracking of methane

Improving methane catalytic decomposition process was deemed an effective approach for hydrogen production. Here, a novel catalyst AlxCo1-xFe2O4 with a variable aluminum content was synthesized via a co-precipitation route for the direct cracking of methane. The catalytic activity of AlxCo1-xFe2O4 was performed in a fixed bed reactor at temperature of 800°C and 20 mL/min of fed gas. A sequence of characterizations, including SEM, BET, XRD, XPS, Raman and TGA for fresh and spent catalysts, was exploited to examine the influence of Alx content on the morphology, porosity, structure, chemical composition, and cation distribution of AlxCo1-xFe2O4. As the Alx content increased in AlxCo1-xFe2O4 their morphology became more fractal and decreased in particle size, lattice parameter, lattice size, while their pore surface increased. Further cation re-distributions from octahedral to tetrahedral sites as Fe3+ and Al3+ relocated in the Tetrahedral site and Oxygen lattice decreased as observed from Raman and XPS results. Catalytic activity studies showed that Alx content of 0.6 in AlxCo1-xFe2O4 lead maximum methane conversion up to ∼ 91.10 % and hydrogen formation rate of 1.780 ×10-3 mol H2 g-1 s-1. The catalytic activity behavior was explained in correlation with the characteristics of spent catalysts.

Research on fatigue performance of “sandwich metal-structured ” composite materials in ultra-low temperature environments

The aim is to investigate the influence of aluminum content in the FeCoCrNiAlx series high-entropy alloys, different aluminum alloy damping layers, and the thickness of damping layers on the fatigue performance of sandwich structure composite material plates after room temperature and low-temperature aging treatment. By using abaqus/fe-safe simulation, as well as liquid nitrogen low-temperature aging treatment and fatigue tensile testing, the differences in fatigue performance between composite materials treated with low-temperature aging and those untreated at room temperature were observed. The increase in aluminum content significantly improves the lifespan of the composite materials, and after low-temperature aging treatment, the change in strength is even more pronounced. Keeping the thickness and material of the upper and lower layers constant, the tensile life of the material, both untreated and treated at low temperatures, shows a significant increasing trend as the thickness of the middle damping layer increases. Other conditions being equal, the iMPact of different damping layer aluminum alloys on fatigue performance is also very evident. In terms of tensile cycles, the ranking is as follows: 7075 > 2A12 > 6061. After low-temperature treatment, the fatigue tension cycles of the 2A12, 6061, and 7075 damping layers under a force of 100 N are respectively 8.66, 7.43, and 2.01 times those of the untreated composite materials.

Analysis of the effectiveness of combining inorganic coagulants with chitosan and bentonite in the treatment of raw water

The production of drinking water often leads to the creation of a high residual concentration of aluminum when mineral salts are used. This concentration must be carefully monitored and controlled. A study was carried out at a drinking water production facility situated in Al Hoceima, Northern Morocco.Throughout this investigation, the treated water from the plant underwent comparative testing, evaluating the effectiveness of chitosan as a flocculant and bentonite as an adjuvant with inorganic coagulants (aluminum sulfate and ferric chloride). The objective was to reduce the residual aluminum concentration in the water after treatment while minimizing the use of inorganic coagulant. Coagulation-flocculation tests, employing a jar test, optimized coagulant dosage while enhancing turbidity and oxidability removal rates.The coagulation-flocculation tests showed that the combination of aluminum sulfate with 10 mg/L of chitosan and 140 mg/L of bentonite, proved to be significantly more effective. Compared to traditional treatment methods using aluminum sulfate alone, this combination reduced the residual aluminum concentration by 38.88%. The optimal parameters were as follows: aluminum sulfate dose of 10 mg/L, a pH of 7.83, an aluminum concentration of <0.07 mg/L, and a turbidity removal efficiency reaching 95.94% and oxidability removal of 42.70%.

Exploring the potential of nitrophosphogypsum and calcined water-treatment plant sludges in mortar mixtures: A study on workability and strength

Mortar mixtures that consider alternative mineral admixtures are of constant research interest to reduce ordinary Portland cement (OPC) content thereby lowering final cost and carbon footprint. An additional concern is the proper management of industrial process residues that could be used in mortar mixes to avoid their disposal in landfills or water bodies. This work investigated the potential of using calcined water treatment plant sludge (CWTPS) and nitrophosphogypsum (NPG) - a byproduct of the fertilizer industry - as partial replacements of OPC in mortar mixtures. For this purpose, this research evaluates the crystallographic, chemical, and physical properties of NPG and CWTPS through X-ray diffraction (XRD), X-ray fluorescence (XRF), and Scanning Electron Microscope (SEM). XRF and XRD findings strongly suggests that CWTPS qualifies as supplementary cementitious materials, due to its high content of silicon and aluminum oxides in a non-crystalline state. On the other hand, NPG could be used as a mineral admixture. The design of mixtures was based on the workability of 85% flow. The evaluation of properties encompasses the measurement of density, compressive strength, durability (pH and sulfate environments), and water absorption. The results demonstrate that incorporating of NPG and CWTPS to mortar mixes, each at a 5% inclusion rate (with a total replacement of 10% of OPC), increase compressive strength by up to 6.65% at 90 days compared to the control group in mortar mixes. However, the inclusion of NPG and CWTPS significantly decreases the workability of mortar mixes by up to 51.49%. The utilization of NPG as a partial replacement for OPC increases the water-to-cement ratio proportionally compared to the control sample, which can be explained by the anhydrite content of this byproduct. For its part, replacing 10% of OPC with NPG and CWTPS results in a 1.99% decrease in resistance after 28 days in sulfated environments compared to specimens cured in lime water. This protection of NPG against sulfate attack on mortars is based on the fact that SO3 saturation hinders the phase change from AFt to AFm during curing, as demonstrated by the XRD results. Additionally, the inclusion of NPG in mortar mixes increases capillary water absorption by up to 19.8%, while CWTPS, due to its pozzolanic nature, reduces it by up to 5.75%. Finally, this study explores the potential combined use of NPG and CWTPS in mortar mixes as a partial replacement for cement, presenting a viable and sustainable alternative for these cementitious-based construction materials.

Microstructure, high temperature mechanical properties and sliding wear behavior of (NiCrW)1-x(Al2O3)x

(NiCrW)1-x(Al2O3)x composites with different nano-Al2O3 ratios (x = 0, 1, 2.5, 5 wt %) were prepared using powder metallurgy techniques. The influence of the Al2O3 content on the microstructure, phase composition, high-temperature mechanical properties, and wide-temperature-range friction and wear performance of the composites was investigated. The corresponding high-temperature strengthening and wear-resistance mechanisms were also investigated. The results indicated that as the alumina content increased, the tensile and compressive strengths of the composites decreased at room temperature (RT). However, at high temperatures (800 °C), the opposite trend was observed. Notably, the composite with 5 wt % Al2O3 exhibits the highest tensile strength (189.20 MPa) and compressive strength (446.61 MPa) at 800 °C. The addition of alumina had a relatively minor impact on the friction coefficient of the composites but significantly affected the wear rate. Specifically, the composite with 5 wt % Al2O3 demonstrates optimal friction and wear performance at high temperatures. This enhancement was primarily attributed to the reinforcement of the mechanical properties of the matrix material owing to the addition of alumina. Additionally, the formation of a friction glaze layer rich in Cr2O3 and NiO oxides on the worn surface contributed to improved wear resistance. This study is important for understanding the performance and applications of metallic materials.

Physical, mechanical properties and microstructure of waste GBFS-based geopolymer incorporated with metakaolin and SiC whiskers(SiCw)

Geopolymer, known as alternative materials to ordinary Portland cement, possess superior properties. This study employed varying dosages of metakaolin from 0 to 30 % and silicon carbide whiskers (SiCw) from 0 to 0.05 % to enhance GBFS-based geopolymer matrix. The process began with the dispersion of SiCw in an alkaline activator through magnetic and ultrasonic stirring, followed by the preparation of the geopolymer. Physical and mechanical characteristics were evaluated to reveal the improvement effects of metakaolin and silicon carbide whiskers on the geopolymer. Techniques such as FTIR, XRD, and SEM-EDS were utilized to analyze the morphology, chemical components, and mineral phases. Pore size distribution and microstructural rearrangement were assessed using MIP and 29Si NMR. Additionally, TG-DTG analysis was conducted to analyze thermal stability. The results indicated that optimal additions of metakaolin and SiCw increased interactions among gel products and induced more chemical reactions, thus exhibiting better mechanical strength and thermal properties. The water absorption and permeable porosity were also improved. The inclusion of SiCw notably provided more nucleation sites and increased the dissolved aluminum content, enriching the phase in the system.

Investigation the Level of Groundwater Pollution with Heavy Metals in Mazar-e-Sharif City

The majority of drinking and consumable water sources for the residents of Mazar-e-Sharif city are supplied from underground water. Climate variations, depletion of underground water, pollution resulting from human activities, agriculture, industrial processes, and urban development have significantly impacted the quality of underground water in this region. In this research, the quality of groundwater in terms of contamination with heavy metals such as manganese, copper, aluminum, iron, cadmium, mercury, lead, and arsenic was investigated. Twenty-four random well samples were collected based on international sampling standards, and temperature and pH parameters were measured on-site. The concentration of heavy metals was measured using an atomic absorption spectrophotometer. Data analysis was performed using Excel and SPSS software, and GIS software was utilized for mapping the sampled points. Laboratory results indicated that the lead concentration in wells W6, W11, W20, and W22 was 0.014, 0.013, 0.02, and 0.012 milligrams per liter, respectively. The aluminum concentration in wells W5, W16, and W17 was 0.6, 0.5, and 0.4 milligrams per liter, respectively, and the cadmium concentration in well W3 was 0.005 milligrams per liter. The concentrations in these wells exceeded the recommended limits set by the World Health Organization (WHO). In the remaining wells, the concentrations of heavy metals were below the WHO limits. Descriptive statistics results showed that copper had the highest average concentration, and arsenic had the lowest concentration. Since underground water is the sole source of drinking and consumable water for the city's residents, it is recommended to conduct a systematic study of heavy metal concentrations in groundwater sources to reduce the adverse effects of contaminated water in certain wells.

Determination of Element Concentration of Brewed Tea Consumed in Iran Using ICP-OES: A Risk Assessment Study.

Tea is a popular drink enjoyed by many people around the world. However, it is important to note that impurities and contaminants in tea can potentially threaten human health when consumed. The main objective of this research is to assess the concentration of 16 trace elements (As, Fe, Al, Co, B, Li, Cd, Ba, Pb, Cr, Zn, Hg, Ni, Mn, Sb, and Sn) present in different types brewed of tea by using the ICP-OES (the inductively coupled plasma optical emission spectrometer) device, and the human health risks related to its use were evaluated. In this study, manganese (Mn) indicated the highest mean concentration in black (917.64µg/kg) and green tea (912.89µg/kg), respectively. Our study showed that the highest mean concentration of element boron (B) was (44.36µg/kg) in Stachys lavandulifolia brewed tea. Among different packaging, tea bag samples had the highest concentration of Mn (1025.65µg/kg) and aluminum (Al) (396.63µg/kg). However, those unpacked posed the lowest content of Mn (188.13µg/kg) and Al (100.47µg/kg). The lead (Pb), mercury (Hg), and cadmium (Cd) concentrations in all samples were lower than the maximum limit of the Iranian standard and the WHO. In general, the amount of tea metal in Iranian samples was higher than in imported samples. Also, increasing the brewing time (10 min) can be effective in the solubility and extraction of metals such as B, Hg, cobalt (Co), iron (Fe), and lithium (Li). Further, the correlation between the amount of metals and type in tea samples was evaluated with principal component analysis. Based on the conducted non-carcinogenic risk assessment by the Monte Carlo simulation, the hazard index (HI), due to ingestion of heavy metals via tea in the 5-min brewing of tea, was 7.39E - 03 and 2.09E - 03, and in the 10-min brewing of tea, it was 3.20E - 02 and 9.07E - 03 for children and adults, respectively. Therefore, there was no significant non-carcinogenic risk from tea consumption.

Silicon extraction from x-ray amorphous soil constituents: a method comparison of alkaline extracting agents

The growing interest in amorphous silica (ASi) within the fields of soil science and ecology underscores the necessity for a reliable protocol to estimate ASi contents in soil. Alkaline wet chemical extraction methods are commonly employed for silicon (Si) extraction from operationally defined (x-ray) amorphous Si phases or short-range ordered mineral phases in soils and marine sediments. In our study we conducted a comparative analysis of four alkaline extraction methods (1% sodium carbonate, 0.5 M sodium carbonate, 0.2 M sodium hydroxide, and 0.1 M Tiron), assessing their extraction selectivity as well as effectiveness using soils artificially enriched with varying, defined amounts of ASi. While extraction effectiveness was evaluated by determining the recovery rate of initially added ASi, extraction selectivity was determined by measuring aluminum (Al) and iron (Fe) concentrations as indicators of the dissolution of non-target mineral phases. Microwave plasma atom emission spectrometry was used to analyze Al, Fe, and Si concentrations in the extracts. Our results indicate that extraction with 0.2 M sodium hydroxide yields the best outcomes in terms of both extraction effectiveness and selectivity. This more recent extraction technique is conducted at the most alkaline pH (13.3) of all four methods tested, but at ambient temperature (21°C) decreasing the dissolution of non-target mineral phases. Though, no wet-chemical extraction used on heterogeneous samples like soil is precisely selective, and thus able to quantify the target analyte only. Hence, data obtained by such procedures still need to be interpreted with caution considering all their limitations.

Origin of fabrics and olivine chemical variations preserved in brachinite and brachinite‐like achondrite meteorites

AbstractBrachinites and brachinite‐like achondrites are olivine‐rich meteorites that represent materials after partial metal–silicate differentiation on multiple early Solar System bodies. Both meteorite types show macroscopic textures of olivine crystals, which make up &gt;70 modal percent of their mineralogy. We investigated the orientations of olivine using electron backscatter diffraction (EBSD) and elemental compositions from paired brachinite‐like achondrites and one brachinite. The olivine orientations are characterized by a strong concentration of [010] axes with maxima perpendicular to the foliation/layering and a concentration of [001] axes distributed in a girdle or, in a few samples, as point maxima. Trace element abundances of the olivine in these meteorites determined using laser ablation inductively coupled plasma–mass spectrometry have uniformly low concentrations of sodium (&lt;300 μg g−1), aluminum (&lt;70 μg g−1), and titanium (&lt;40 μg g−1) that are distinct from olivine in chondrites or within terrestrial lavas. Instead, brachinite and brachinite‐like olivine compositions broadly overlap those of olivine from melt‐depleted mantle lithologies on Earth. Evidence from olivine trace element geochemistry, in conjunction with mineral fabrics, supports that these meteorites formed as melt residues on their host planetary body(ies).

Thermogravimetry as a research tool for the development of an ammonium sulphate roasting process for selective metal extraction from minerals

AbstractThe ammonium sulphate roasting process involves reacting mineral-bearing materials with ammonium sulphate via a solid–solid roasting process and subjecting the resulting roast residue to aqueous leaching. This process enables the simultaneous, non-selective co-extraction of strategic metals from the starting materials. However, effective separation of the extracted metals is often mandatory to produce quality products of high purity. In this study, the combined application of thermogravimetric analysis, X-ray powder diffraction and inductively coupled plasma optical emission spectrometry confirmed the non-selectivity of the process when applied to a South African diamond mine residue residue roasted with ammonium sulphate in a 1:2 mass ratio (m/m) at 450 °C for 2 h, with magnesium, iron and aluminium being co-extracted into water-soluble metal sulphates. Thermogravimetry was then applied to develop a multi-step, multi-temperature selective roasting process using mixtures of pure commercial metal sulphate salts. The first step of the modified process successfully separated iron and aluminium sulphates from magnesium-sulphates in the roast residues by thermally decomposing soluble iron and aluminium sulphates into insoluble oxides via calcination at 750 °C for 2 h. This temperature was lower than the one at which magnesium sulphates convert into magnesium oxide. In the second and final step, iron and aluminium were recovered from the oxide minerals via solid–solid re-roasting with ammonium sulphate at 450 °C for 1 h, causing the oxides to revert back to their water-soluble sulphate forms. The effectiveness of the modified process was subsequently verified using a diamond mine residue, showing that the soluble iron and aluminium contents in the magnesium-bearing leachate could be reduced by over 90%.

Aluminum dynamics in nitrogen‐saturated Andisols in Tokyo

AbstractThe debate over whether forests around the Tokyo metropolitan area are nitrogen (N) saturation persists, as atmospheric N deposition in throughfall has decreased. This decrease is evidenced by a notable decline in samples collected in the 1990s (especially 1991–1992 and 1995). This decline can be attributed to a reduction in nitrogen oxide (NOx) emissions from automobiles. The acidity derived from N deposition can increase aluminum (Al) mobility. We conducted a monitoring study from September 2010 to December 2021 to elucidate the effects of decreased N deposition on Al concentrations and flux in a forested Andisol. Throughfall and soil‐percolated water samples were collected under stands of Japanese cedar and Japanese cypress in Hachioji, Tokyo (Field Museum Tamakyuryo). Major inorganic ions were determined by ion chromatography. Total Al concentrations were determined using atomic absorption spectrometry after concentration under acidic conditions. Aluminum and nitrate () concentrations were significantly correlated in the both Japanese cedar and Japanese cypress stands. In the case of the Japanese cedar stand, Al concentrations tended to decrease over time from November 2010 to May 2015. Based on stepwise multiple regression analysis, acid load associated with N transformation ([H+]load) was chosen as the sole factor affecting Al mobilization in the Japanese cedar stand. Decreased N deposition affects Al dynamics via a decrease in [H+]load.

Nanocomposite membrane of alumina nanofibers / poly ether sulfone as blood-contacting biomaterials

This study aimed to determine the physicochemical, mechanical, antifouling, and hemocompatibility effects of electrospun alumina (γ-Al2O3) nanofibers incorporated into polyether sulfone membranes. The γ-Al2O3 nanofibers with mean diameter of 81 ±27 nm were successfully produced using sol-gel and electrospinning methods. By changing the weight ratio of Al2O3 nanofibers to Poly ether sulfone (PES) solution (0, 0.03, 0.05, and 0.1 w/w), different membranes were fabricated using the phase inversion method. With the addition of 0.03 (w/w) Al2O3 nanofibers, the membrane’s pore size increased, but decreased with further nanofiber addition. Energy dispersive spectroscopy mapping analysis revealed that Al3+ ions were successfully distributed throughout the membranes except for those containing 0.1 (w/w) Al2O3. The alumina nanofibers increase the crystallinity and mechanical strength of the PES membrane, while reducing its surface roughness. Alumina content increased in PES membranes resulted in a reduction in flux reduction, improved BSA rejection and antifouling properties, and decreased platelet adhesion and hemolysis, improving hemocompatibility. Overall, PES-0.05 with a mean radius pore of 9.60± 0.90, highest BSA rejection (98.2±0.4) and FRR (72), the lowest platelet adhesion and hemolysis ratio was considered as an optimum membrane.

Towards wake-up free ferroelectrics and scaling: Al-doped HZO and its crystallographic texture

Ferroelectric (FE) hafnium zirconium oxide (HZO) is an excellent candidate for data storage applications. However, it has some reliability limitations such as imprint and retention. Herein, we explore Al doping of HZO to overcome these limitations. FE behavior is tuned by the aluminum (Al) concentrations in the films and by annealing temperature. A correlation is done between electrical behavior, crystallographic texture, and FE phases determined by grazing-incidence X-ray diffraction (GIXRD) measurements. Reduced coercive field (2Ec) values and wake-up free HZO-based ferroelectrics are explored. We show the tunability of remanent polarization (2Pr) and 2Ec with respect to Al-doping concentration and anneal temperature, hence crystallographic texture.

From marble waste to monocarboaluminate binder: role of sodium aluminate composition, calcined clay type, and curing temperature

This study focuses on the synthesis of a monocarboaluminate (MCA)-based binder by treating marble waste (MW) powder with sodium aluminate (SA). The aim is to investigate the influence of various parameters, including the alumina modulus (M A) of SA, different contents of calcined clays with varying alumina levels, and curing temperatures, on the performance and phase composition of the resulting binder. The results demonstrate that the combination of SA and MW leads to the formation of an MCA-based binder, which exhibits a high compressive strength of up to 28 MPa after seven days of curing. Additional phases such as gibbsite, pirssonite, and gaylussite are observed, indicating the occurrence of a cationic exchange reaction between MW and SA, as confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The stability of the resulting binder is primarily influenced by the M A value, with higher values associated with greater stability. Regardless of the type of calcined clay used, incorporating calcined clay results in the formation of a calcium aluminate silicate hydrate (CSAH) phase alongside MCA, contributing to the improved stability of the hardened binder over time. Notably, calcined clay with a higher alumina content exhibits the highest strength at all curing ages. Furthermore, increasing the curing temperature up to 100 °C significantly enhances the early strength, which correlates with the formation of the kotoite phase at the expense of the MCA phase.

Evaluation of aluminum tolerance diversity in Avena sativa L. from the VIR collection

Background. Oat is an important food and feed cereal crop in Russia. The area under oats is 10 million ha worldwide, and 3 million ha in Russia. Acid soils with excessive content of exchangeable aluminum occupy almost every third hectare in the exUSSR territory. Oats are relatively resistant to unfavorable soil factors. Among cereal crops, oat is second only to rye and triticale in terms of resistance to exchangeable Al forms. Despite the crop’s high environmental plasticity, an important condition for obtaining sustainable oat yields is the development of new cultivars with resistance to adverse environmental factors, including metal toxicity and high soil acidity.The objective of this work was to search for oat cultivars resistant to soil stressors (excess of Н+ and Al3+) for use in breeding for edaphic resistance.Materials and methods. The research material included 687 oat accessions from the VIR global plant genetic resources collection. The accessions underwent laboratory evaluation of their aluminum tolerance at the initial growth and development stages using the method of measuring radicle growth after the exposure to aluminum stress. Reproducibility of the used modification of the method was mathematically proved.Results and discussion. Significant variation in the resistance to the studied stressor was observed among the accessions. The regions acting as sources of valuable aluminum resistance genes were identified for the crop. The accessions selected for their high resistance to exchangeable aluminum can be used in breeding programs to develop high-yielding oat cultivars with edaphic resistance.

Effect of composition on the thermal properties and structure of M-Al-Si-O-N glasses, M = Na, Mg, Ca

The primary objective of this study is to explore the relationship between the composition, structure, and thermal characteristics of M-Al-Si-O-N glasses, with M representing sodium (Na), magnesium (Mg), or calcium (Ca). The glasses were prepared by melting in a quartz crucible at 1650 °C and AlN precursor (powder) was utilized as a nitrogen source. The measured thermal properties studied were glass transition temperature (Tg), crystallization temperature (Tc), glass stability, viscosity, and thermal expansion coefficient (α). The findings indicate that increasing the aluminum content leads to higher glass transition, crystallization temperatures, and viscosities. In contrast, fragility values increase with the Al contents, while modifier elements and silicon content influence thermal expansion coefficient values. FTIR analysis revealed that in all glasses, the dominant IR bands are attributed to the presence of Q2 and Q3 silicate units. The effect of Al is observed as a progressive polymerization of the silicate network resulting from the glass-forming role of Al2O3. In most samples, the Q4 silicate mode was also observed, strongly related to the high Al content. Overall, the study shows that the complexity of composition-property correlations where the structural changes affect the properties of Mg/Ca-based oxynitride glasses has potential implications for their use in various technological fields.

Study on the evolutionary mechanism of the cavity inside aluminum nanoparticles while reacting with oxygen

Aluminum nanoparticles are often considered attractive choices for fuels in energetic materials. In this study, molecular dynamics simulation with the reactive force field (ReaxFF) was used to study the oxidation process of three different particle sizes (4 nm, 5 nm, 6 nm) of ANPs (aluminum nano-particles). The cavity formation mechanism was obtained during the ANPs oxidation process. The cavity size, the oxide layer thickness, and the active aluminum content of ANPs with time were obtained. The results indicated that the formation of cavities is highly dependent on particle size. Large particle size prevents the formation of cavities. In 0–100 ps, the average growth rate of the oxide layer is 0.33, 0.25, and 0.20 nm/ps, respectively. Within 100–250 ps, the average growth rate of the oxide layer is −0.017, 0.038, and 0.117 nm/ps, respectively. Our results emphasize the effect of particle size on cavity formation, which provides insights into the atomic-scale oxidation mechanism of metal nanoparticles.

The arising of ferromagnetism in Al-doped Mn2(Ga1−xAlx)C MAX phases

The magnetic properties of ordered MAX phases Mn2(AlxGa1−x)C (x = 0.125, 0.25, 0.5, 0.75 and 0.875) have been studied within the DFT-GGA. We have found that increase of Al atom at A-site leads to the formation of the ferromagnetic phase with large magnetization of about 3.6 μB/f.u. The investigation of the phase stability is performed by comparing the total energy of the MAX phases with that of a set of competitive phases for calculation of the phase formation enthalpy. Up to a concentration of Al atoms x = 0.7 the compound remains thermodynamically stable. The exchange constants analysis shows the crucial role of exchange interactions between manganese atoms along the c-axis in forming of ferromagnetism. The magnetic transition temperature of Mn2(AlxGa1−x)C alloys increases with increase of the aluminum concentration.

Optimizing 2-Nitrophenol and Chromium Adsorption from Water with Aluminium Oxide via Response Surface Methodology

Optimizing 2-Nitrophenol and Chromium Adsorption from Water with Aluminium Oxide via Response Surface Methodology