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1.
J Environ Manage ; 370: 122403, 2024 Sep 07.
Article in English | MEDLINE | ID: mdl-39244933

ABSTRACT

This study focuses on developing a g-C3N4/Sb2S3 heterojunction photocatalyst with different g-C3N4 to Sb2S3 weight ratios (1:1, 1:3, and 3:1) for degrading tetracycline (TC) pollutants. The 1:3 ratio (13 GS) exhibited optimal photocatalytic performance, achieving 99% TC degradation under sunlight within 120 min, compared to 78.4% under visible light and 38% under UV light. The 13 GS catalyst demonstrated strong reusability, maintaining 80% degradation efficiency after six cycles. Scavenger experiments identified hydroxyl radicals as crucial for TC degradation, with DMSO reducing activity by 30%. The photocatalyst also showed high hydrogen production with an apparent quantum efficiency (AQE) of 19.8% under standard conditions, and improved AQE in acidic (23%) and basic (22.7%) conditions, and with CH3OH (23.2%). This g-C3N4/Sb2S3 heterojunction offers a promising solution for degrading toxic contaminants and has the potential for solar-powered applications.

2.
Carbohydr Polym ; 346: 122588, 2024 Dec 15.
Article in English | MEDLINE | ID: mdl-39245483

ABSTRACT

Aiming at dealing with organic and inorganic pollutants dissolved in aquatic environments, we introduce self-assembled fluorescent nanocomposite hydrogel based on a binary polysaccharide network (xanthan gum/chitosan) embedding nitrogen-doped carbon quantum dots not only as a hybrid solid optical sensor for detecting Cr(VI) ions but also to remove anionically charged contaminants Cr(VI) and methyl orange (MO) by acting as an adsorbent. This fluorescent nanocomposite achieved a detection limit of 0.29 µM when used to detect Cr(VI) and demonstrated a fluorescence quantum yield of 59.7 %. Several factors contributed to the effectiveness of the adsorption of Cr(VI) and MO in batch studies, including the solution pH, dosage of the adsorbent, temperature, initial contamination level, and contact time. Experimental results showed 456 mg/g maximum adsorption capacity at pH 4 for MO compared to 291 mg/g at pH 2 for Cr(VI) at 25 °C. In addition to conforming to Langmuir's model, Cr(VI) and MO's adsorption kinetics closely matched pseudo-second-order. Using thermodynamic parameters, the results indicate that Cr(VI) and MO adsorb spontaneously and exothermically. Recycling spent adsorbent for Cr(VI) and MO using NaOH at 0.1 M was possible; the respective adsorption efficiency remained at approximately 82.2 % and 83 % after the fifth regeneration cycle.

3.
Sci Rep ; 14(1): 20894, 2024 Sep 08.
Article in English | MEDLINE | ID: mdl-39245771

ABSTRACT

This study proposes an innovative approach to combat the escalating threat of antibiotic resistance in bacteria by introducing a novel ZnO-propolis nanocomposite (ZnO-P NCs). The overuse of antibiotics, particularly during events like the COVID-19 pandemic, has intensified bacterial resistance, necessitating innovative solutions. The study employs a cost-effective and controllable biosynthesis method to produce ZnO nanoparticles (ZnO-NPs), with propolis extract crucially contributing to the reduction and stabilization of Zn2+ ions. A biodegradable nano-propolis matrix is then created by incorporating ZnO-NPs, forming the ZnO-P NCs. Structural stability is confirmed through FT-IR and Zeta potential analysis, while nanoscale properties are validated via TEM, SEM, and XRD analyses. The antimicrobial efficacy of various substances, including propolis, nano propolis, ethanolic propolis extract, ZnO-NPs, and ZnO-P NCs, is assessed against Gram-negative and Gram-positive bacteria, alongside a comparison with 28 antibiotics. Among the bacteria tested, Pseudomonas aeruginosa PAO1 ATCC15692 was more sensitive (40 mm) to the biosynthesized nanocomposite ZnO-P NCs than to ZnO-NPs (38 mm) and nanopropolis (32 mm), while Escherichia coli was resistant to nanopropolis (0 mm) than to ZnO-NPs (31 mm), and ZnO-P NCs (34 mm). The study reveals a synergy effect when combining propolis with green-synthesized ZnO-NPs in the form of ZnO-P NCs, significantly improving their efficiency against all tested bacteria, including antibiotic-resistant strains like E. coli. The nanocomposite outperforms other materials and antibiotics, demonstrating remarkable antibacterial effectiveness. SEM imaging confirms the disruption of bacterial cell membranes by ZnO-NPs and ZnO-P NCs. The study emphasizes the potential applications of ZnO-NPs integrated into biodegradable materials and underscores the significance of the zinc oxide-propolis nanocomposite in countering antimicrobial resistance. Overall, this research offers a comprehensive solution to combat multidrug-resistant bacteria, opening avenues for novel approaches in infection control.


Subject(s)
Anti-Bacterial Agents , Microbial Sensitivity Tests , Nanocomposites , Propolis , Zinc Oxide , Zinc Oxide/chemistry , Zinc Oxide/pharmacology , Propolis/chemistry , Propolis/pharmacology , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Nanocomposites/chemistry , Pseudomonas aeruginosa/drug effects , Drug Resistance, Bacterial/drug effects , Humans , Spectroscopy, Fourier Transform Infrared , Metal Nanoparticles/chemistry
4.
Nano Converg ; 11(1): 36, 2024 Sep 09.
Article in English | MEDLINE | ID: mdl-39249580

ABSTRACT

The oxide and halide perovskite materials with a ABX3 structure exhibit a number of excellent properties, including a high dielectric constant, electrochemical properties, a wide band gap, and a large absorption coefficient. These properties have led to a range of applications, including renewable energy and optoelectronics, where high-performance catalysts are needed. However, it is difficult for a single structure of perovskite alone to simultaneously fulfill the diverse needs of multiple applications, such as high performance and good stability at the same time. Consequently, perovskite nanocomposites have been developed to address the current limitations and enhance their functionality by combining perovskite with two or more materials to create complementary materials. This review paper categorizes perovskite nanocomposites according to their structural composition and outlines their synthesis methodologies, as well as their applications in various fields. These include fuel cells, electrochemical water splitting, CO2 mitigation, supercapacitors, and optoelectronic devices. Additionally, the review presents a summary of their research status, practical challenges, and future prospects in the fields of renewable energy and electronics.

5.
Sci Rep ; 14(1): 20301, 2024 Sep 01.
Article in English | MEDLINE | ID: mdl-39218929

ABSTRACT

The development of decarbonized synthesis approaches is a critical step in the fabrication of ammonia, an indispensable chemical and a potential carbon-neutral energy carrier. In this regard, the photocatalytic production technology has gained ample attention as a sustainable alternative to energy-intensive and environmentally detrimental Haber-Bosch process. Here, we present cobalt ferrite nanoparticles supported on microporous ZSM-5 type ferrisilicate zeolite as a desirable novel photocatalyst for the ammonia generation. The zeolite introduced as a microporous support increasing the catalytically active sites. A straightforward one-pot sol-gel method was used to synthesize cobalt ferrite (CoFe2O4) and CoFe2O4/ferrisilicate (CF/FS) nanocomposites with various weight percentages (10, 25 and 50%) of CoFe2O4. The photocatalytic performances of the samples in the production of ammonia were investigated under visible light irradiation. The highest rate of NH4+ production (484.74 µmol L-1 h-1) was achieved using the CF50%/FS photocatalyst. The distribution of < 50 nm-sized CoFe2O4 nanoparticles on the surface of the zeolite, as demonstrated by TEM images, and extensive BET surface areas are presented as convincing evidences for the improved photocatalytic activity paticularly in CF50%/FS photocatalyst.

6.
Sci Technol Adv Mater ; 25(1): 2393568, 2024.
Article in English | MEDLINE | ID: mdl-39238510

ABSTRACT

Sugarcane-based products are inherently rich in elements such as silicon, carbon and nitrogen. As such, these become ideal precursors for utilization in a wide array of application fields. One of the appealing areas is to transform them into nanomaterials of high interest that can be employed in several prominent applications. Among nanomaterials, sugarcane products based on silica nanoparticles (SNPs), carbon dots (CDs), metal/metal oxide-based NPs, nanocellulose, cellulose nanofibers (CNFs), and nano biochar are becoming increasingly reported. Through manipulation of the experimental conditions and choosing suitable starting precursors and elements, it is possible to devise these nanomaterials with highly desired properties suited for specific applications. The current review presents the findings from the recent literature wherein an effort has been made to convey new development in the field of sugarcane-based products for the synthesis of the above-mentioned nanomaterials. Various nanomaterials were systematically discussed in terms of their synthesis and application perspectives. Wherever possible, a comparative analysis was carried out to highlight the potential of sugarcane products for the intended purpose as compared to other biomass-based materials. This review is expected to stand out in delivering an up-to-date survey of the literature and provide readers with necessary directions for future research.


This review focuses on sugarcane-derived nanomaterials such as silica, nano cellulose, nanofibers, nanocrystals and metal/nonmetal nanoparticles and their application in various energy and environmental fields.

7.
Article in English | MEDLINE | ID: mdl-39240432

ABSTRACT

The extensive use of pharmaceuticals has increased their presence in the environment, posing significant ecological and public health concerns. The current study reports the magnetic nanocomposite (M-ABAC) synthesis using the algal-bacterial sludge as the precursor for activated carbon and evaluates its potential in fluoroquinolone antibiotics removal. The activated carbon from algal-bacterial sludge was composited with Fe3O4 nanoparticles using the co-precipitation method. The M-ABAC was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), Brunauer-Emmett-Teller (BET) analysis, and vibrating sample magnetometry (VSM). M-ABAC was employed for antibiotic ciprofloxacin (CIP) removal by combined adsorption and heterogenous Fenton degradation. The adsorption studies reveal that the Langmuir isotherm best fits the experimental data, with a maximum adsorption capacity of 81.6 mg/g. Pseudo-second-order kinetic model well describes adsorption kinetics. Fenton catalytic degradation was performed using H2O2 as the activating agent. The optimal H2O2 dosage was observed to be 10 mM. A CIP adsorptive removal efficiency of 75% was observed at 2 g/L dosage of M-ABAC in a 200 ppm CIP solution. Simultaneous adsorption and Fenton catalytic degradation further enhanced the removal efficiency to 92%. Radical scavengers experiment revealed that the hydroxyl radical (•OH) was the dominant reactive oxidation species. The degradation products of the CIP were identified using liquid chromatography quadrupole time-of-flight mass spectroscopy (LC-QTOF-MS). The possible CIP degradation mechanisms include decarboxylation, piperazine moiety degradation, defluorination, and hydroxylation.

8.
Front Chem ; 12: 1441650, 2024.
Article in English | MEDLINE | ID: mdl-39233921

ABSTRACT

Plant-based materials and edible films have emerged as promising alternatives to conventional packaging materials, offering sustainable and environmentally friendly solutions. This mini-review highlights the significance of plant-based materials derived from polysaccharides, proteins, and lipids, showcasing their renewable and biodegradable nature. The properties of edible films, including mechanical strength, barrier properties, optical characteristics, thermal stability, and shelf-life extension, are explored, showcasing their suitability for food packaging and other applications. Moreover, the application of 3D printing technology allows for customized designs and complex geometries, paving the way for personalized nutrition. Functionalization strategies, such as active and intelligent packaging, incorporation of bioactive compounds, and antimicrobial properties, are also discussed, offering additional functionalities and benefits. Challenges and future directions are identified, emphasizing the importance of sustainability, scalability, regulation, and performance optimization. The potential impact of plant-based materials and edible films is highlighted, ranging from reducing reliance on fossil fuels to mitigating plastic waste and promoting a circular economy. In conclusion, plant-based materials and edible films hold great potential in revolutionizing the packaging industry, offering sustainable alternatives to conventional materials. Embracing these innovations will contribute to reducing plastic waste, promoting a circular economy, and creating a sustainable and resilient planet.

9.
Sci Rep ; 14(1): 20511, 2024 Sep 03.
Article in English | MEDLINE | ID: mdl-39227659

ABSTRACT

A two-step methodology has been developed utilizing the models of Paul and Takayanagi to determine the modulus of polymer halloysite nanotube (HNT) products. Initially, HNTs and the adjacent interphase are considered as pseudoparticles, and their modulus is evaluated using the Paul model. Subsequently, the modulus of a nanocomposite, consisting of a polymer medium and pseudoparticles, is predicted by Takayanagi equation. The impacts of various factors on the modulus of the products are analyzed, and the results from the two-step method are compared with experimental data from different samples. It has been observed that the modulus of samples progressively increases with an increase in interphase depth. Also, a higher interphase modulus contributes to an enhanced modulus of samples. Nevertheless, excessively high interphase moduli (Ei > 60 GPa) result in only a marginal improvement in the modulus of nanocomposites. Additionally, narrower HNTs are advantageous for producing stronger samples, though the modulus of the nanocomposites slightly diminishes at very high HNT radii (R > 55 nm). The outputs of two-step method agree with the experimental moduli of various HNT-filled systems.

10.
Int J Biol Macromol ; : 135278, 2024 Sep 02.
Article in English | MEDLINE | ID: mdl-39233157

ABSTRACT

Cellulose nanofibers (CNF) create a physical barrier preventing contact with corrosive substances and improving corrosion prevention. Oil palm fronds (OPF), the primary source of underused biomass waste from plantations, were processed into CNF. The OPF-CNF, mixed with hydroxyethyl cellulose as the matrix, forms a nanocomposite. Corrosion analysis using electrochemical methods demonstrated that copper coated with cellulose-rich nanocomposite containing 5 % CNF had a significantly decreased corrosion rate with an efficiency of 97.92 %. This CNF-based coating, combining barrier and passivation mechanisms, enhances performance, providing a competitive, eco-friendly alternative to conventional coatings.

11.
J Chromatogr A ; 1735: 465267, 2024 Sep 05.
Article in English | MEDLINE | ID: mdl-39241404

ABSTRACT

A novel nanofibrous double-layered biosorbent was fabricated by electrospinning polyethersulfone (PES) doped with a natural deep eutectic solvent (DES), composed of choline chloride (ChCl) and caffeic acid (CFA) in a 3:1 molar ratio, onto a bacterial cellulose (BC) substrate. The pristine PES/DES@BC biosorbent was employed in a thin film-solid phase microextraction (TF-SPME) to extract 12 multiclass pesticides from water. Characterization techniques, including ATR-FTIR, FT-NMR, SEM, and nitrogen adsorption/desorption isotherms, confirmed the nanofibrous structure of the electrospun PES-DES and BC biopolymer. The method was validated for matrix effect, specificity, reproducibility, limits of quantification (0.03-0.10 µg/L), and enrichment factor (7-14). Matrix-match calibration linearity ranged from 0.03 to 500 µg/L, with determination coefficients (r²) between 0.9884 and 0.9994. Intra-day and inter-day relative standard deviations (RSDs) were 1.2-3.6 % and 7.0-9.3 %, respectively. The composition of the biosorbent and the fabrication reproducibility across different batches were also thoroughly examined. The accuracy was evaluated by measuring extraction recoveries in six environmental water samples, which ranged from 75 to 105 % (RSDs < 9.0 %). Furthermore, the sustainability of the method was evaluated with the Analytical Eco-Scale and Analytical Greenness metrics. To our knowledge, this study represents the first synthesis and combination of [ChCl:[CFA] DES with PES to create a double-layered nanofiber biosorbent, as well as its application for extracting various pesticide groups from water samples.

12.
Environ Pollut ; : 124892, 2024 Sep 04.
Article in English | MEDLINE | ID: mdl-39241949

ABSTRACT

Lead ions (Pb2+) are heavy metal environmental pollutants that can significantly impact biological health. In this study, the synthesis of a ternary nanocomposite, ErVO4/P@g-C3N4/SnS2, was achieved using a combination of hydrothermal synthesis and mechanical grinding. The as-fabricated photoelectrochemical (PEC) sensor was found to be an ideal substrate for Pb2+ detection with high sensitivity and reliability. The ErVO4/P@g-C3N4/SnS2/FTO was selected as the substrate because of its remarkable and reliable photocurrent response. The Pb2+ sensor exhibited a low detection limit of 0.1 pM and a broad linear range of 0.002 to 0.2 nM. Moreover, the sensor exhibited outstanding stability, selectivity, and reproducibility. In real-time applications, it exhibited stable recovery and a low relative standard deviation, ensuring reliable and accurate measurements. The as-prepared PEC sensor was highly stable for the detection of Pb2+ in different water samples. This promising characteristic highlights its significant potential for use in the detection of environmental pollutants.

13.
Int J Biol Macromol ; 279(Pt 3): 135316, 2024 Sep 03.
Article in English | MEDLINE | ID: mdl-39236953

ABSTRACT

Application of fertilizers is a routine method in agriculture to increase the fertility of plants However, conventional fertilizers have raised serious health and environmental problems in recent years. Therefore, the development of biodegradable superabsorbent hydrogels based on natural polymers with the capability for fertilizer controlled release has attracted much interest. In the current research, a novel nanocomposite hydrogel based on gelatin and carboxymethyl cellulose polymers enriched with an iron based metal- organic framework (MIL-53 (Iron)) was prepared. The prepared nanocomposite hydrogel was loaded with NPK fertilizer to obtain a slow release fertilizer system. The structural properties of the nanocomposite hydrogel were investigated using FTIR, XRD, and SEM techniques. The swelling and fertilizer release behavior of the nanocomposite hydrogel were evaluated in conditions. Results showed that by adding iron-based metal organic framework to the hydrogel matrix, the water absorption capacity of the hydrogel system was increased to 345.8 (g/g). Fertilizer release studies revealed that the release of fertilizer from the nanocomposite matrix has a slow and continuous release pattern. Therefore, the synthesized nanocomposite has an appropriate strength and high potential to be used as a slow-release fertilizer system.

14.
Talanta ; 281: 126714, 2024 Aug 29.
Article in English | MEDLINE | ID: mdl-39232253

ABSTRACT

The indiscriminate use of pesticides in agriculture demands the development of devices capable of monitoring contaminations in food supplies, in the environment and biological fluids. Simplicity, easy handling, high sensitivities, and low limits-of-detection (LOD) and quantification are some of the required properties for these devices. In this work, we evaluated the effect of incorporating gold nanoparticles into indigo carmine-doped polypyrrole during the electropolymerization of films for use as an acetylcholinesterase (AChE) enzyme-based biosensor. As proof of concept, the pesticide methyl parathion was tested towards the inhibition of AChE. The enzyme was immobilized simply by drop-casting a solution, eliminating the need for any prior surface modification. The biosensors were characterized with cyclic voltammetry, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The assays for the detection of methyl parathion with films containing polypyrrole, indigo carmine and AChE (PPy-IC-AChE) presented a sensitivity of 5.7 µA cm-2 g-1 mL and a LOD of 12 nmol L-1 (3.0 ng L-1) with a linear range from 1.3 x 10-7 mol L-1 to 1.0 x 10-5 mol L-1. The introduction of gold nanoparticles (AuNP) into the film (PPy-IC-AuNP-AChE) led to remarkable improvements on the overall performance, such as a lower redox potential for the enzymatic reaction, a 145 % increase in sensitivity (14 µA cm-2 g-1 mL), a wider detection dynamic range (from 1.3x10-7 to 1.0x10-3 mol L-1), and a very low LOD of 24 fmol L-1 (64 ag mL-1). These findings underscore the potential of using AuNPs to improve the enzymatic performance of biosensor devices.

15.
Mikrochim Acta ; 191(9): 506, 2024 08 04.
Article in English | MEDLINE | ID: mdl-39097837

ABSTRACT

Using a chemiluminescence reaction between luminol and H2O2 in basic solution, an ultrasensitive electrochemiluminescence (ECL) aptasensor was developed for the determination of tobramycin (TOB), as an aminoglycoside antibiotic. Ti3C2/Ni/Sm-LDH-based nanocomposite effectively catalyzes the oxidation of luminol and decomposition of H2O2, leading to the formation of different reactive oxygen species (ROSs), thus amplifying the ECL signal intensity of luminol, which can be used for the determination of TOB concentration. To evaluate the performance of the electrochemiluminescence aptasensor and synthesized nanocomposite, different methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses were performed. The considerable specific area, large number of active sites, and enhanced electron transfer reaction on this nanocomposite led to the development of an ECL aptasensor with high sensitivity and electrocatalytic activity. After optimizing the preparation method and analysis conditions, the aptasensor revealed a wide linear response ranging from 1.0 pM to 1.0 µM with a detection limit of 18 pM, displaying outstanding accuracy, specificity, and response stability. The developed ECL sensor was found to be applicable to the determination of TOB in human serum samples and is anticipated to possess excellent clinical potentials for detecting other antibiotics, as well.


Subject(s)
Aptamers, Nucleotide , Biosensing Techniques , Electrochemical Techniques , Limit of Detection , Luminescent Measurements , Nanocomposites , Tobramycin , Nanocomposites/chemistry , Humans , Electrochemical Techniques/methods , Aptamers, Nucleotide/chemistry , Luminescent Measurements/methods , Biosensing Techniques/methods , Tobramycin/blood , Tobramycin/analysis , Luminol/chemistry , Anti-Bacterial Agents/blood , Anti-Bacterial Agents/analysis , Hydrogen Peroxide/chemistry , Nickel/chemistry , Titanium/chemistry
16.
Chemosphere ; 364: 143018, 2024 Aug 05.
Article in English | MEDLINE | ID: mdl-39111674

ABSTRACT

In this paper, we report hydroxyapatite derived from egg-shell biowaste embedded on diglycolamic acid functionalized graphitic carbon nitride nanocomposite (abbreviated as HAp@D-gCN). The compositional and morphological characteristics of HAp@D-gCN were evaluated using scanning electron microscope, X-ray diffraction, BET, FTIR techniques and surface charge using zeta potential measurement. The sorption of U(VI) species on HAp@D-gCN was investigated through batch studies as a function of pH, contact time, initial U(VI) concentration, adsorbent dosage and ionic strength. The adsorption of U(VI) onto HAp@D-gCN was confirmed by FTIR, XRD and EDS elemental mapping. Adsorption kinetics follow pseudo second order model and it attains equilibrium within 20 min. Adsorption isotherm data correlates well with Langmuir isotherm model with a maximum sorption capacity of 993.6 mg of U(VI) per gram of HAp@D-gCN at 298K. U(VI) can be leached from the loaded adsorbent using 0.01 M Na2CO3 as desorbing agent and its sorption capacity remains unaffected even after 4 adsorption-desorption cycles. Hence, the present study reveals that HAp@D-gCN nanocomposite could serve as an environmental friendly material with potential application in environmental remediation.

17.
Sensors (Basel) ; 24(15)2024 Jul 26.
Article in English | MEDLINE | ID: mdl-39123909

ABSTRACT

The integration of nanocomposite thin films with combined multifunctionalities on flexible substrates is desired for flexible device design and applications. For example, combined plasmonic and magnetic properties could lead to unique optical switchable magnetic devices and sensors. In this work, a multiphase TiN-Au-Ni nanocomposite system with core-shell-like Au-Ni nanopillars embedded in a TiN matrix has been demonstrated on flexible mica substrates. The three-phase nanocomposite film has been compared with its single metal nanocomposite counterparts, i.e., TiN-Au and TiN-Ni. Magnetic measurement results suggest that both TiN-Au-Ni/mica and TiN-Ni/mica present room-temperature ferromagnetic property. Tunable plasmonic property has been achieved by varying the metallic component of the nanocomposite films. The cyclic bending test was performed to verify the property reliability of the flexible nanocomposite thin films upon bending. This work opens a new path for integrating complex nitride-based nanocomposite designs on mica towards multifunctional flexible nanodevice applications.

18.
Molecules ; 29(15)2024 Aug 05.
Article in English | MEDLINE | ID: mdl-39125110

ABSTRACT

Increased environmental pollution and the shortage of the current fossil fuel energy supply has increased the demand for eco-friendly energy sources. Hydrogen energy has become a potential solution due to its availability and green combustion byproduct. Hydrogen feedstock materials like sodium borohydride (NaBH4) are promising sources of hydrogen; however, the rate at which the hydrogen is released during its reaction with water is slow and requires a stable catalyst. In this study, gold nanoparticles were deposited onto mesoporous carbon to form a nano-composite catalyst (AuNP-MCM), which was then characterized via transmission electron microscopy (TEM), powder X-ray diffraction (P-XRD), and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). The composite's catalytic ability in a hydrogen evolution reaction was tested under varying conditions, including NaBH4 concentration, pH, and temperature, and it showed an activation of energy of 30.0 kJ mol-1. It was determined that the optimal reaction conditions include high NaBH4 concentrations, lower pH, and higher temperatures. This catalyst, with its stability and competitively low activation energy, makes it a promising material for hydrogen generation.

19.
Polymers (Basel) ; 16(15)2024 Jul 26.
Article in English | MEDLINE | ID: mdl-39125159

ABSTRACT

In this study, the effect of boric acid (H3BO3) on fiber-reinforced layered composites was investigated. Glass fiber-reinforced epoxy composites were used, and the effects of boric acid on thermal and mechanical properties were investigated. For this purpose, composite plates were manufactured by adding boric acid (BA) to the epoxy in different ratios (0, 0.5, 1, and 1.5% by weight). Tensile tests, compression tests, and shear tests were performed to determine the mechanical properties of these plates, and DSC, TGA, and DMA analyses were performed to determine their thermal properties. SEM and EDS analyses were performed on the specimens to examine their morphologies. Furthermore, examinations were conducted on how BA affected the specimens' failure behavior. In the study, it was found that, except for the compressive strength, the mechanical properties were improved by the added BA. The highest tensile strength, shear strength, modulus of elasticity, shear modulus, and Poisson's ratio were obtained from 0.5% BA-added specimens and were 24.78%, 8.75%, 25.13%, 11.24%, and 12.5% higher than the values obtained from 0% BA-added specimens, respectively. The highest loss and storage modulus were obtained from 0% and 0.5% BA-added specimens, respectively. The specimens' glass transition temperatures were decreased by the addition of BA; the specimen with a 1% addition of BA had the lowest value. Furthermore, interlayer delamination and fiber/matrix failure were observed in all BA-added specimens.

20.
Polymers (Basel) ; 16(15)2024 Jul 31.
Article in English | MEDLINE | ID: mdl-39125209

ABSTRACT

This study focused on synthesizing a cellulose-based hydrogel nanocomposite as a green hydrogel by adding a microcrystalline cellulose (MC) solution to carboxymethyl cellulose sodium (CMC-Na) with citric acid as a cross-linker. Y2O3 nanoparticles were incorporated during hydrogel preparation in different ratios (0.00% (0 mmol), 0.03% (0.017 mmol), 0.07% (0.04 mmol) and 0.10% (0.44 mmol)). FTIR analysis confirmed the cross-linking reaction, while XRD analysis revealed the hydrogels' amorphous nature and identified sodium citrate crystals formed from the reaction between citric acid and CMC-Na. The swelling test in deionized water (pH 6.5) at 25 °C showed a maximum swelling percentage of 150% after 24 h in the highest nanoparticle ratio. The resulting cellulose hydrogels were flexible and exhibited significant antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The synthesized cellulose-based hydrogel nanocomposites are eco-friendly and suitable for medical applications.

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