XRD Analysis Research Articles

Hydrogen generation via NaBH4 hydrolysis over cobalt-modified niobium oxide catalysts

The increasing concentration of CO₂ in the atmosphere, primarily driven by fossil fuel combustion, is a major contributor to global warming and one of the most pressing environmental challenges of the 21st century. In response, the development of sustainable energy technologies, such as hydrogen (H₂) production, has become crucial in the global transition to a low-carbon economy. In this study, we explored the catalytic activity of cobalt-modified niobium-based catalysts for hydrogen generation through the hydrolysis of NaBH₄. The catalysts were characterized using XRD, FTIR, XPS, SEM-EDX, and N₂ adsorption-desorption. XRD analysis revealed that the synthesized Nb₂O₅ (Nb₂O₅ Synt.) and Nb₂O₅/Co (Nb₂O₅/Co Synt.) exhibited amorphous structures, while the commercial Nb₂O₅ (Nb₂O₅ Com.) and its Co-modified composite displayed orthorhombic phases. The Nb₂O₅/Co Synt. catalyst achieved a surface area of 33.1 m2/g, significantly surpassing that of the commercial Nb₂O₅. The Nb₂O₅/Co Synt. catalyst exhibited superior catalytic activity, yielding 250 mL of hydrogen in 60 min, in contrast to other catalysts that showed no activity under identical conditions. This enhanced activity was attributed to the presence of surface hydroxyl groups and metallic Co nanoparticles, following the Langmuir-Hinshelwood bimolecular mechanism. Temperature was identified as a critical factor in the H₂ production rate, with a calculated activation energy of 11.37 kJ/mol. Moreover, the Nb₂O₅/Co Synt. catalyst demonstrated excellent reusability, maintaining stable performance after multiple reaction cycles, highlighting its potential for sustainable hydrogen production.

Nano Hydroxyapatite (Nano-HA) Based on Pholas Orientalis Shells and Degradation Analysis

Millions of tons of seashells are produced every day as waste around the world. These underutilized seashells waste was executed as calcium precursor by researcher to synthesis the nano-hydroxyapatite (nano-HA). Nano-HA was successfully synthesised from Pholas Orientalis seashells waste via the chemical precipitation method. Different sintering temperatures were implemented to evaluate the physicochemical criteria of nano-HA. The obtained powders were examined by various physicochemical methods such as XRD, FTIR, FESEM, EDX and degradation analysis. The peaks in XRD and FTIR analysis the HA is successfully produced. The FESEM images on the other hand showing the HA particle in nano size range with rice-like structure. Meanwhile, a variation of Ca/P ratio can be observed in respect to sintering temperatures. The Ca/P ratio for HA-WS, HA-S500 and HA-S700 sample is 1.78, 2.03 and 1.57 respectively. Different sintering temperatures result in different crystallinity value which consequently affects its degradation profile.

Physicochemical and biological evaluation of ‘click’ synthesized vinyl epoxide-chitosan film for active food packaging

Chitosan (Cs) being a natural biopolymer serves as an excellent template to construct active packaging materials for achieving sustainable development. In this study, Cs was chemically modified via epoxide ring opening click reaction using vinyl epoxide to obtain a novel chitosan vinyl epoxide (Cs-VE) derivative with hydroxyl and olefinic functional groups. The Cs-VE transparent film was fabricated through the eco-friendly solution casting technique. A meticulous investigation into the chemical structure and physicochemical properties of the synthesized films was conducted using FT-IR, 1H NMR and XRD analyses. The thermal stability and homogeneity of the film were verified by thermogram and FE-SEM images respectively. Improved mechanical properties (tensile strength of 24.64 MPa and 12.08 % elongation at break) and excellent UV-light blocking ability (9.3 % transmittance at 350 nm and 22.15 % transparency at 600 nm) were observed. Also, important parameters such as water vapor permeability (WVP), swelling degree, water solubility and UV-barrier properties were found to be adequate for food packaging application. Similarly, enhanced antioxidant activity with 27.2 % and 73.6 % radical scavenging against DPPH and ABTS radicals respectively was observed for the synthesized Cs-VE film. The film showed antimicrobial activity against both bacteria and fungi. These results along with food packaging studies on Grewia asiatica fruit established the developed Cs-VE film as a suitable candidate for active food packaging application.

Synthesis, Characterization, DFT Calculations, and Pharmacological Activity of Azo Dye Ligand and Its Cu(II) Complex Comprising Nitrogen and Oxygen Donor Atoms

ABSTRACTCoupling the diazonium salt of sulfadiazine with dibenzoylmethane afforded the 4‐(2‐(1,3‐dioxo‐1,3‐diphenylpropan‐2‐ylidene)hydrazinyl)‐N‐(pyrimidin‐2‐yl)benzene sulfonamide ligand (HL). The ligand (HL) and its Cu(II) complex structure have been investigated via magnetic attraction testing, TGA, FTIR, UV–visible, XRD, and CHN analyses. The spectrum data indicate that the ligand demonstrates monobasic bidentate behavior via deprotonating opposite the oxygen atom of the carbonyl (CO) group and linking using the NH of the hydrazone group (NNH). Copper (II) complex present in octahedral structure. A number of TGA steps (Ea, A, ΔH*, ΔS*, and ΔG*) had their dynamical characteristics computed and described using the Coats–Redfern and Horowitz–Metzger formulas. Molecular studio programmer was utilized to perform density functional theory (DFT) calculations in order to investigate the ideal configuration of HL and its Cu(II) complex. The HL and its copper (II) complex exhibited antitumor effects against MCF‐7 and HepG‐2 cell lines. Furthermore, the width of the inhibition zone was employed to evaluate the in vitro antibacterial effect of HL and a specific complex towards Gram‐negative organisms Escherichia coli (E. coli) and Gram‐positive organisms Staphylococcus aureus. The ligand and its Cu(II) complex were examined using both the viscosity and spectrum of absorption of calf thymus DNA binding experiments.

Reply to Comment on “Singh R, Vadlamani R, Bajpai S & Maurya AS (2024) Strontium Isotope Stratigraphy of Marine Oligocene–Miocene Sedimentary Successions of Kutch Basin, Western India. Geological Journal, 1–20. DOI: 10.1002/gj.4961”

ABSTRACTThis response addresses the comments made by Saraswati et al. on our recent publication in Geological Journal. In our study, we used a multi‐analytical screening approach, including visual, XRD and trace element analysis, to evaluate diagenetic alteration of carbonate shell samples. Contrary to the claims made by Saraswati et al. our findings are based on well‐preserved samples with minimal alteration. The Sr‐isotope data from the Khari Nadi Formation (23.07–18.09 Ma) are largely consistent with existing biostratigraphic constraints, but suggest a possible extension of the upper age limit into the Burdigalian. Our Sr‐isotope ages for the Chhasra Formation (15.11–12.29 Ma) are younger than those suggested previously, based on larger benthic foraminifers, but largely corroborate recent nannoplankton data. As a result of the new age data from Kutch, we suggest that the sedimentation rates, derived from multiple samples, increased significantly from the Oligocene to Miocene. We assert that ‘established’ ages are also subject to refinements as the rock units become amenable to new dating techniques. We welcome any criticism that is constructive, and remain open to any further data that could refine or challenge our interpretations.

Hydrothermal Growth Zinc Oxide Nanorods for pH Sensor Application

The aim of this work is to apply synthesized zinc oxide (ZnO) Nanorods using hydrothermal (HTL) growth technique for pH sensor application. The highly crystallite of ZnO Nanorods was obtained by anneal the growth ZnO Nanorods in furnace at 200 °C for 2 hours. Besides that, XRD analysis shows the produced ZnO Nanorods belonged to the (002) plane. Furthermore, Scanning Electron Microscope (SEM) images confirm that the ZnO Nanorods with hexagonal-faceted structural were successfully produced by HTL growth technique. In addition, Ultraviolet–visible (UV-Vis) spectrophotometer analysis shows that the synthesized ZnO belongs to the wide band gap semiconductor material. The growing ZnO Nanorods were then subjected to electrical measurement with various pH levels. The outcome demonstrates that the current rises as the solution changes from acidic to alkaline. Overall, our study shows a relationship between the electrical as well as the structural characteristics of ZnO Nanorods at various pH levels.

Biofilm Demolition by [AuIII(N^N)Cl(NHC)][PF6]2 Complexes Fastened with Bipyridine and Phenanthroline Ligands; Potent Antibacterial Agents Targeting Membrane Lipid.

The development of new antibacterial drugs is essential for staying ahead of evolving antibiotic resistant bacterial (ARB) threats, ensuring effective treatment options for bacterial infections, and protecting public health. Herein, we successfully designed and synthesized two novel gold(III)- NHC complexes, [Au(1)(bpy)Cl][PF6]2 (2) and [Au(1)(phen)Cl][PF6]2 (3) based on the proligand pyridyl[1,2-a]{2-pyridylimidazol}-3-ylidene hexafluorophosphate (1•HPF6) [bpy= 2,2'-bipyridine; phen= 1,10-phenanthroline]. The synthesized complexes were characterized spectroscopically; their geometries and structural arrangements were confirmed by single crystal XRD analysis. Complexes 2 and 3 showed photoluminescence properties at room temperature and the time-resolved fluorescence decay confirmed the fluorescence lifetimes of 0.54 and 0.62 ns respectively; which were used to demonstrate their direct interaction with bacterial cells. Among the two complexes, complex 3 was found to be more potent against the bacterial strains (Staphylococcus aureus, Gram-positive and Pseudomonas aeruginosa, Gram-negative bacteria) with the MIC values of 8 µg.mL-1 and 16 µg.mL-1 respectively. Studies revealed the binding of the complexes with the fundamental phospholipids present in the cell membrane of bacteria, which was found to be the leading cause of bacterial cell death. Cytotoxicity was evaluated using an MTT assay on 293T cell lines; emphasizing the potential therapeutic uses of the Au(III)-NHC complexes to control bacterial infections.

Synthesis and Characterization of ZnO Nanoparticles by Pulsed Laser Ablation in Liquid Using Different Wavelengths for Antibacterial Application

In this paper, the synthesis of colloidal solution of ZnO nanoparticles by PLAL using an Nd: YAG laser with 1064 nm and 532 nm wavelengths is described. The optical, morphological, structural, wettability and antibacterial activities were studied. The XRD analysis showed the hexagonal wurtzite structure while the UV-vis indicated the blue shift of the absorption peak due to the surface plasmon of the nanoparticle, which showed significant changes in color behavior. The FE-SEM revealed a uniformed spherical shape with a partial size range of 20.50–21.48 nm for ZnO at 1064 and 57.08–59.87 nm for ZnO at 532nm. Also, the concentration measurement indicated that the concentration of ZnO prepared at 1064 nm is 26.7 μg ml-1 and 63 μg ml-1 at 532 nm due to the relevance of high energy to the Zn plate and little distortion in the water and high absorption of short wavelength. Finally, the optical density of the antibacterial activity has been investigated, and both concentrations have good antibacterial activity at 12 h. The ZnO prepared at 532 nm has higher antibacterial activity because it has a high concentration of nanoparticles for both S. aureus and E. coli. Finally, the cell viability for ZnO synthesis with both 1064 nm and 532 nm indicates that this material has high biocompatibility and could be used for medical applications.

Study on the Applicability of Deterioration Detection Techniques for Sandstone Heritage in Multi Environment using MLP-Attention Model

Abstract. Stone cultural heritage, encompassing a broad spectrum of artifacts such as stone artworks, buildings, tools, and utensils, represents one of the most significant categories of cultural heritage. However, the conservation of these cultural heritage faces challenges from the process of deterioration. This degradation not only compromises the structural integrity of the heritage but also results in the loss of invaluable historical information. Thus, there emerges a critical demand for effective methods to detect and assess the condition of stone cultural heritage, enabling timely and precise conservation interventions. Here we obtained sandstone samples under different deteriorative environments through laboratory-simulated deterioration experiments and employed a variety of detection technologies to capture a series of changes in the deterioration detection parameters during the sandstone deterioration process. Subsequently, a deep learning model was established to correlate the detection parameters with the degree of stone deterioration. A SHAP analysis was then conducted to determine the contribution of various parameters to the degree of stone weathering under different experimental environments, providing recommendations for selecting appropriate detection technologies and indicators adapted to different deterioration environments. To further analyze the deterioration processes of the stone samples, XRD analysis was conducted to observe changes in mineral composition throughout the deterioration process. SEM images were utilized to examine the changes in micro-morphology and the internal pore structure associated with deterioration. This study provides a basis for the scientific design of deterioration detection schemes by selecting the most suitable testing technology for optimal deterioration assessment under specific environmental conditions.

Characterization of the natural fibers extracted from the aninga's stem and development of a unidirectional polymeric sheet.

A unidirectional sheet was made with oriented fibers in an epoxy matrix. Natural fibers were extracted from the stem of Montrichardia linifera (Arruda) Schott., traditionally known as aninga, characterized and used to produce a unidirectional polymeric sheet. FTIR, XRD, SEM, TG, and DTG analyses were performed to characterize these cellulose fibers. Peaks observed at 1024cm- 1, 1600cm- 1, and 3328cm- 1 revealed the stretching vibration of the O-H bond, the stretching of the carbonyl in hemicellulose, and the vibration of aromatic rings, respectively. XRD analysis demonstrated a crystallinity index of 62.21%. Morphological analysis revealed the microstructural quality of the fiber surface, with grooves for mechanical anchoring, as well as its interior, which is composed of microfibrils. EDS analysis confirmed the presence of the main elements composing natural fibers, with carbon being the major component (70%). The thermal stability of aninga fibers was up to 450 ºC for the degradation of 50% of their initial mass. The mechanical properties of untreated aninga fibers showed a tensile strength of 332MPa and an elastic modulus of 13.000MPa. The unidirectional sheet had a tensile strength of 4.5MPa and an elasticity modulus of 332.9MPa. These outcomes ensured that aninga fiber is considered high-performance (> 200MPa) and can be used for internal automobile components.

Eco-friendly Synthesis of Gold Nanoparticles of Methanolic Extract of Bauhinia vahlii Leaves and Evaluation of Tyrosinase Inhibitory Activity

Background: The green synthesis of gold nanoparticles (AuNPs) using natural materials has gained significant attention in recent years due to their eco-friendliness and potential applications in various fields. Methods: The present study aimed at the green synthesis and anti-hyperpigmentation potential of gold nanoparticles (AuNPs) using a methanolic extract of Bauhinia vahlii. Furthermore, the green synthesis of the AuNPs was confirmed by UV-visible, FT-IR, XRD, and EMDEX analysis. The size and surface topological significance of green synthesized AuNPs were evaluated through Scanning Electron Microscope and Field Emission Scanning Electron Microscopy. Results: The size of the synthesized AuNPs was found to be in the range of 100-1000 nm. The tyrosinase inhibitory activity of AuNPs was evaluated through the mushroom tyrosinase inhibitory assay method. The tyrosinase inhibitory activities of crude extract, AuNPs, and Kojic acid were found to be 98.7 ±0.7, 75±1.3 and 41±1.1 μg/ml, respectively. Conclusion: Hence, green synthesized AuNPs of B. vahlii leaf extract may be used as a potent antihyperpigmentation agent in the market of nano cosmeceuticals.

Synergistic insights to ion-doped hydroxyapatite: bridging XRD, electrical impedance, dielectric characteristics, and antibacterial properties

ABSTRACT In this work, ion-doped hydroxyapatite materials were synthesized using the sol-gel technique. XRD analysis confirmed the purity of the products, with no secondary peaks observed. Doping with manganese, lithium, potassium, and zinc ions resulted in a crystalline size of 47–48 nm. Fourier transform infrared spectroscopy validated the structural bands, while scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed nano-rod-like particles with sizes ranging from 30 to 80 nm in length and 13 to 40 nm in width. Impedance spectroscopy and dielectric relaxation studies showed electrical behaviour following the Maxwell-Wagner mechanism and non-Debye type relaxation. The materials exhibited strong antibacterial properties, making them promising for medical implant applications.

Photocatalytic degradation of ampicillin antibiotics in aqueous solution utilizing ZnFe2O4/MWCNTs/TiO2 ternary nanocomposite under solar light irradiation

In this study, a novel photocatalyst composed of zinc ferrite (ZnFe₂O₄), titanium dioxide (TiO₂), and multi-walled carbon nanotubes (MWCNTs) was successfully synthesized via the hydrothermal method, and evaluated for the degradation of ampicillin (AMP) in aqueous solutions. The synthesized nanocomposites were thoroughly characterized using various analytical techniques, including XRD, HR-SEM, HR-TEM, EDX, UV-Vis, FT-IR, BET, and XPS analysis. Crystallite sizes of 24.18 nm for ZnFe₂O₄ and 17.8 nm for TiO₂ were determined. The composite exhibited a band gap of 1.4 eV, indicating its enhanced photocatalytic activity. The photocatalytic performance was assessed under varying conditions, including different nanocomposite dosages (0.3–1 g/L), AMP concentrations (10–50 mg/L), and pH values (2–12). The optimal AMP degradation efficiency of 99.2 % was achieved using 0.7 g/L of the photocatalyst, 10 mg/L of AMP, and a pH of 12 under 90 min of solar irradiation. These optimal parameters were then applied to evaluate AMP degradation using ZnFe2O4, TiO2, and ZnFe2O4/MWCNTs individually, with the degradation rate analyzed using a pseudo-first-order model. The superior photocatalytic efficiency can be primarily attributed to improved charge transfer dynamics and effective electron-hole separation, enabled by the doping of MWCNTs. Hydroxyl radicals (OH•) were identified as the primary reactive species responsible for AMP degradation. Furthermore, the catalyst retained 91 % of its photocatalytic efficiency after eight consecutive cycles, demonstrating excellent stability and reusability. These results underscore the potential of the ZnFe₂O₄/MWCNTs/TiO₂ composite as a highly effective and sustainable photocatalyst for removing pharmaceutical pollutants from aquatic environments.

Research on improving permeability of granite reservoir: Polyhydrogen chelating acid acidizing

ABSTRACT Acidization is a highly effective technique for increasing oil well productivity. Therefore, it is critical to study effective stimulation of low-permeability granite reservoirs using acidification. Using the granite reservoir of Baobab oilfield in Chad as the research object, the properties of reservoir rocks were tested using XRD and rock thin section analysis. Dissolution experiments, core flooding experiments, and CT scanning were used to investigate the increased permeability and changes in the pore structure of the cores during acidification. The minerals in the rocks are primarily plagioclase, kalifeldspar, and quartz, with trace amounts of calcite, chlorite, magnetite, illite, biotite, hornblende, sphene, and sericite. At 80°C and 10 mL of main acid injection, polyhydrogen chelating acid (6% HCl + 5% SA601 + 7% SA701) improved granite permeability more than mud acid (8% HCl + 2% HF) and fluoroboric acid (8% HCl + 8% HBF4), with permeability increase of 3.68. The CT three-dimensional images of the rocks show that both the cores acidified with polyhydrogen chelating acid and mud acid formed continuous acid-etched wormholes, while the cores acidified with fluoroboric acid did not. Compared to the mud acid, the core acidified by the polyhydrogen chelating acid produced more visible acid-etched wormholes. Meanwhile, the polyhydrogen chelating acid was more effective at improving the pore throats and expanding the flow channels in the core. This study serves as a reference for the application of acidification and increasing production in low-permeability granite reservoirs.

Enhanced magnetocaloric effect in nano-sized Dy3Ga5O12 garnet: A comparative study on the effect of solid-state and wet-chemical synthesis

This study investigates the magnetic and structural properties of bulk and nanosized Dy3Ga5O12 (DGG) synthesized through solid-state and wet chemical methods to assess the impact of particle size. The single-phase composition of the synthesized materials was determined by X-ray diffraction analysis (XRD). XRD and TEM analysis revealed the formation of nanosized DGG via the wet chemical route at 750 °C/2h. The nano DGG exhibits enhanced magnetocaloric effect compared to its bulk counterpart, suggesting its potential as a promising material for low-temperature magnetic refrigeration applications.

Silicomanganese fume-based alkali-activated mortar: experimental, statistical, and environmental impact studies.

This paper evaluates the flowability and strength properties of alkali-activated mortar produced using silicomanganese fume (SiMnF) as the sole binder, combined with alkaline activators and sand, cured at room temperature (23 ± 1 °C). A total of 18 mixes were prepared by varying binder content (370, 470, and 570 kg/m3), alkaline activator content (33, 43, and 53% of binder by weight), and NaOH concentration (8 M and 12 M). The SiMnF-based alkali-activated pastes were characterized using SEM, XRD, and FTIR techniques to study morphology, mineral composition, and functional groups, respectively. Statistical modeling, including analysis of variance (ANOVA) and response surface method (RSM), was performed to optimize the mixes, and a life cycle assessment was conducted to evaluate the environmental impact of the developed SiMnF-based alkali-activated mortars (SiMnF-AAM). The experimental results showed that an optimal mix design with 470kg/m3 SiMnF, 43% alkaline activator content, and NaOH concentrations of 8M and 12M achieved the best balance of flow and strength. XRD and FTIR analyses confirmed that Nchwaningite was the primary reaction product, with secondary phases including magnetite, manganese ferrite, and potassium feldspar, influenced by alkali concentration. The SiMnF-based mixtures had a significantly lower CO₂ footprint (0.08kg CO₂/kg) compared to the cement-based mix, with alkali activators being the primary contributors to emissions. The developed SiMnF-AAM mixes, cured at room temperature, exhibited improved workability, mechanical properties, and reduced environmental impact, making them adaptive to real-life applications.

ITZ properties of LWA surroundings in high strength mortar according to LWA/sand with relative humidity

The internal moisture content significantly influences the quality and durability of cement-based composite materials. However, reliable methods to analyze the moisture retention of concrete and mortar are lacking, particularly in relation to internal curing with lightweight aggregates (LWA). In this study, the internal moisture retention of mortar with different lightweight aggregate/sand (L/S) ratios was investigated while considering the absorption characteristics of LWA. Furthermore, the impact of internal moisture retention on the development of the interface transition zone (ITZ) between the LWA and cement matrix was analyzed. Additionally, compressive strength development was evaluated over different curing periods (3, 7, 28, 56, and 90 days) under internal curing conditions. The results showed that the L/S ratio, which is directly proportional to the amount of moisture absorbed, enhanced the compressive strength and plastic hardness, contributing to the development of depletion of internal moisture in the mortar was could be observed. The moisture consumption for different types of LWA was analyzed using CT scanning. XRD and SEM-EDS analyses confirmed the abundant presence of hydration products in the ITZ. This study demonstrates that the L/S ratio that considers the LWA absorption characteristics, can serve as a critical parameter for precisely correlating the curing time and compressive strength in internally cured mortars.

Extraction of Aluminum Oxide from Local Kaolin Clay Deposits in Ethiopia

The need for aluminum is growing worldwide, which has sparked interest in finding alternate ways to make alumina from materials other than bauxite, particularly clays. This article examines the use of sodium carbonate as a leaching agent in the lime sintering process to recover alumina from kaolin. Excavated from Tarmaber, Ethiopia, kaolin clay contains a content of 32.88%, which has a relatively good composition. Collecting and grounding raw kaolin to micrometer-level particle size is the first task. The recovery of kaolin alumina was studied at sintering temperatures of (T<sub>1</sub>=800°C, T<sub>2</sub>= 900°C & T<sub>3</sub>=1000°C) at different sintering times of (t<sub>1</sub>=1 hr, t<sub>2</sub>=2 hrs & t<sub>3</sub>=3 hrs). After the raw material was burned at the given temperatures and times, it was cooled for the night in the furnace and leached with different concentrations of sodium carbonate (M<sub>1</sub>=50 g/l, M<sub>2</sub>=60 g/l & M<sub>3</sub>=70 g/l). The response surface methodology (RSM) in combination with the central composite design was used to optimize the operating parameters. The optimization result shows that the optimal conditions were a calcination temperature of 953.84°C, a sintering time of 2.99 h, and a leaching agent concentration of 70 g/l. At this optimal condition, the yield of Alumina was 1.05 g of 20 g of Kaolin clay. The resulting Alumina was crystalline in structure (from XRD analysis), contains 89.05% Al<sub>2</sub>O<sub>3</sub> (from silicate analysis) and a large broad band between 400-1000 cm<sup>-1</sup> is attributed to Al-O-Al stretching of Alumina (from FT-IR analysis). So, it is possible to conclude that alumina production from no bauxite ores is possible.

Study of alkali and acetylation treatments on sisal fibers compatibility with low-amine/epoxy stoichiometric ratio

Sisal fibers are one of the most commercially utilized as reinforcing agents in composite materials. However, sisal fibers are very hydrophilic because they contain many hydroxyl groups, so their interfacial bonding is low when mixed with a non-polar polymer matrix. One method to improve the fiber-matrix interfacial bond is to modify the sisal fiber surface with chemical treatment. This study evaluated the influence of various chemical treatments on the tensile properties and interfacial adhesion of sisal fibers reinforced with low-amine/epoxy stoichiometric ratio resin. The sisal fibers were subjected to a series of treatments, including 2 wt% alkali for 4 h, acetylation for 1 h, and a combined alkali and acetylation treatment. The FT-IR analysis confirmed the success of the acetylation process by the presence of the carbonyl signal (1728 cm−1). The XRD analysis indicated that the crystallinity index of the sisal fiber (65 %) was increased after alkali (75 %) and acetylation (66 %) treatments. The alkali-treated sisal fibers showed the highest tensile strength (728 MPa) but the lowest interfacial shear strength (17.7 MPa). The acetylated-treated sisal fibers exhibited the highest tensile modulus (44.5 GPa) and interfacial shear strength (25 MPa). However, the combination of alkali and acetylation treatments reduced the tensile strength of the fiber from 659 to 619 MPa. The TGA results revealed that the maximum degradation temperature of sisal fibers (344 °C) was increased after alkali (349 °C), acetylation (348 °C), and a combination of alkali and acetylation (350 °C) treatments. The results suggest that acetylation treatment is highly beneficial for advanced composite applications.

A Carbon Capture and Utilization Process for the Production of Solid Carbon Materials from Atmospheric CO2 - Part 2: Carbon Characterization.

This article is the second part of a study reporting the results of a novel carbon capture and utilization (CCU) process, which converts atmospheric CO2 into solid carbon materials. The CCU process combines direct air capture (DAC) with catalytic methanation, which is then followed by methane pyrolysis in a reactor filled with liquid tin. While Part 1 discussed the performance of the overall process and individual process steps regarding conversions and yields, Part 2 characterizes the solid carbon products obtained under various synthesis conditions. The effects of the pyrolysis temperature and the composition of the gas mixture from the methanation step on the solid carbon product are analyzed. Carbon powder is synthesized from methane with either H2 or CO2 as most important impurity. Carbon samples are characterized using SEM, TEM, Raman spectroscopy, XPS and XRD analysis. Very thin, disordered carbon flakes, soot aggregates and large carbon onions are identified as the main solid products of the process. Their formation mechanisms in the liquid metal-filled pyrolysis reactor are discussed.