Search Results (63)

The present work proposes the optimization of the co-digestion of vinasse, filter cake, and deacetylation liquor in a continuous reactor by adding iron(III) oxide (Fe₃O₄) nanoparticles (NPs), comparing the results with a previous reactor operation without NPs. Initially, tests were carried out in batches with different NP concentrations, resulting in 5 mg L⁻¹ as the best concentration to be added in the continuous reactor along the increments of the applied organic load rate (OLR). Methane (CH₄) production reached a maximum value of 2.8 ± 0.1 NLCH₄ gVS⁻¹ (normal liter methane per gram of volatile solids), and the organic matter removal reached 71 ± 0.9% in phase VI (OLR of 5.5 gVS L⁻¹ day⁻¹). This production was 90% higher than the reactor co-digestion operation without NPs. The anaerobic digestion (AD) development was stable with stable organic acid (OA) concentrations, indicating the predominance of the propionic acid route to produce CH₄. The main methanogenic Archaea identified was Methanoculleus, indicating that the predominant metabolic route was that of acetate (SAO) coupled with hydrogenotrophic methanogenesis. The use of Fe₃O₄ NPs managed to improve the AD from the first-generation and second-generation (1G2G) ethanol production residues and stimulated microbial community growth, without modifying the preferable metabolic pathways. Full article

Over recent years, the ‘green’ chemistry approach to synthesizing nanoparticles has made significant developments. Because of their unique features, nanoparticles have received a lot of attention. The use of a bioflocculant to promote the environmentally friendly synthesis of copper nanoparticles is described in this paper. Copper nanoparticles were biosynthesized using bioflocculant which was produced from a yeast, Pichia kudriavzevii. The chemical reduction approach was used to synthesize copper nanoparticles (CuNPs) using a bioflocculant as a capping agent. Characterization of the as-synthesized copper nanoparticles was conducted using Fourier transform infrared (FT-IR) spectroscopy, UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX). The FT-IR spectra revealed characteristic peaks at 3267, 2956, 1656, 1059, and 511 cm⁻¹ for the bioflocculant, while for the bioflocculant passivated CuNPs, the characteristic peaks were at 3482 (-OH), 3261, 1640, 1059, 580, and 519 cm⁻¹ (Cu-O). These peaks revealed that functional groups such as hydroxyls, amines, and copper oxide bonds were present. The UV-Vis analysis showed surface plasmon resonance (SPR) at an absorbance range of 500–600 nm, with peak maxima at 555 and 575 nm for the as-synthesized CuNPs. The XRD pattern revealed planes such as (200) and (220) at 2θ = 43 and 52°, and the particle size (30 nm) was determined by the Debye–Scherrer equation. The transmission electron microscopy analysis revealed a spherical-shaped particle with an average size of 20 nm. The EDX analysis of the as-synthesized CuNPs revealed the presence of the element Cu, which was not present in the EDX image of the bioflocculant used in the synthesis of the CuNPs; this indicated the success of biosynthesis. Full article

In this work, α-Ag₂WO₄ particles with different cross-sections were obtained using the co-precipitation method at different synthesis temperatures. The samples were characterized by X-ray diffraction (XRD), field-scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The antimicrobial activity was analyzed using the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) methods against the Escherichia coli and Salmonella spp. gram-negative bacteria. The antimicrobial tests against Escherichia coli and Salmonella spp. indicated that concentrations of 2.5–5 mg/mL and 5 mg/mL completely inhibit its growth, respectively. The antimicrobial activity was analyzed employing band-edge positions for ROS generations and the superficial distribution of Ag⁺ species that contribute to antimicrobial activity. Quantum-chemical calculations were used at the DFT level to investigate the surface-dependent reactivity of α-Ag₂WO₄, and we demonstrated how the antimicrobial properties could be tailored by the geometry and electronic structure of the exposed surfaces, providing guidelines for the morphology design. Full article

Magnetite (Fe₃O₄) nanoparticles were extracted from the shells of freshwater Limnoperna fortunei (Dunker 1857) and marine Perna perna (Linnaeus 1758) mussels, followed by full physical and chemical characterization using ICP-OES, UV–Vis, EDX, Raman, and XRD spectroscopy, VSM magnetometry, and SEM and TEM techniques. Considering their spatial distribution, the ferrimagnetic particles in the shells had low concentration and presented superparamagnetic behavior characteristics of materials of nanometric size. Transmission electron microscopy (TEM, especially HRTEM) indicated round magnetic particles around 100 nm in size, which were found to be aggregates of nanoparticles about 5 nm in size. The TEM data indicated no iron oxide particles at the periostracum layer. Nevertheless, roughly round iron (hydr)oxide nanoparticle aggregates were found in the nacre, namely, the aragonite layer. As the aragonite layer is responsible for more than 97% of the shell of L. fortunei and considering the estimated size of the magnetic nanoparticles, we infer that these particles may be distributed homogeneously throughout the shell. Full article

This work demonstrates the possibility of electrochemical formation of Ge-Sn-O nanostructures from aqueous solutions containing germanium dioxide and tin (II) chloride at room temperature without prior deposition of fusible metal particles. This method does not require complex technological equipment, expensive and toxic germanium precursors, or binding additives. These advantages will make it possible to obtain such structures on an industrial scale (e.g., using roll-to-roll technology). The structural properties and composition of Ge-Sn-O nanostructures were studied by means of scanning electron microscopy and X-ray photoelectron spectroscopy. The samples obtained represent a filamentary structure with a diameter of about 10 nm. Electrochemical studies of Ge-Sn-O nanostructures were studied by cyclic voltammetry and galvanostatic cycling. Studies of the processes of lithium-ion insertion/extraction showed that the obtained structures have a practical discharge capacity at the first cycle ~625 mAh/g (specific capacity ca. 625 mAh/g). However, the discharge capacity by cycle 30 was no more than 40% of the initial capacity. The obtained results would benefit the further design of Ge-Sn-O nanostructures formed by simple electrochemical deposition. Full article

The objective of this work was to prepare different concentrations of liposomes based on lecithin containing quercetin, and evaluate their effect on the properties of galactomannan films obtained from Cassia grandis seeds. Quercetin-loaded lecithin liposomes (QT-LL) were obtained by the ethanol injection method by incorporating quercetin in different concentrations in a previously prepared suspension of lecithin liposomes in water. Following characterization of QT-LLs by zeta potential and dynamic light scattering, QT-LL with 75 µg quercetin/mL suspension was incorporated at different concentrations in galactomannan films. The films obtained were characterized for color, solubility, moisture content (MC), water vapor permeability (WVP), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. The size of lecithin liposomes with no quercetin was statistically than those containing quercetin above 50 µg/mL. All the QT-LLs presented a low polydispersity index, even considering their significant differences and similar values for zeta potential. The films displayed a rough surface and the galactomannan structure was confirmed by FTIR. Additionally, the amorphous nature of the polysaccharide was observed by XRD. The films were luminous, with a predominant yellow tendency and low opacity. The incorporation of QT-LL in galactomannan films did not lead to statistical differences for solubility and MC, while significant differences were observed for WVP. Galactomannan films were shown to be a promising structure for the incorporation of lecithin liposomes loaded with quercetin, pointing at promising applications for different applications. Full article

The design and necessity of corrosion-resisting nanocarbon nanocomposites have been investigated for cutting-edge aerospace applications. In this regard, nanocarbon nanofillers, especially carbon nanotubes, graphene, nanodiamond, etc. have been used to fill in various polymeric matrices (thermosets, thermoplastics, and conducting polymers) to develop anti-rusting space-related nanocomposites. This review fundamentally emphases the design, anti-corrosion properties, and application of polymer/nanocarbon nanocomposites for the space sector. An electron-conducting network is created in the polymers with nanocarbon dispersion to assist in charge transportation, and thus in the polymers’ corrosion resistance features. The corrosion resistance mechanism depends upon the formation of tortuous diffusion pathways due to nanofiller arrangement in the matrices. Moreover, matrix–nanofiller interactions and interface formation play an important role in enhancing the corrosion protection properties. The anticorrosion nanocomposites were tested for their adhesion, contact angle, and impedance properties, and NaCl tests and scratch tests were carried out. Among the polymers, epoxy was found to be superior corrosion-resisting polymer, relative to the thermoplastic polymers in these nanocomposites. Among the carbon nanotubes, graphene, and nanodiamond, the carbon nanotube with a loading of up to 7 wt.% in the epoxy matrix was desirable for corrosion resistance. On the other hand, graphene contents of up to 1 wt.% and nanodiamond contents of 0.2–0.4 wt.% were desirable to enhance the corrosion resistance of the epoxy matrix. The impedance, anticorrosion, and adhesion properties of epoxy nanocomposites were found to be better than those of the thermoplastic materials. Despite the success of nanocarbon nanocomposites in aerospace applications, thorough research efforts are still needed to design high-performance anti-rusting materials to completely replace the use of metal components in the aerospace industry. Full article

The purpose of this study is to modify all physicochemical properties of glycine–copper sulphate single crystals, such as crystal habits, molar mass, thermal stability, optical activity, and electrical properties. The novelty of this study is growth of glycine–copper sulphate single crystals doped by a low concentration of silver nanoparticles (SNPs) that improved both crystal habits and physicochemical properties. The originality of this work is that trace amounts of SNPs largely increased the crystal size. Crystals have molar stoichiometric formula [glycine]_0.95, [CuSO₄·5H₂O]_0.05 in the absence and presence of silver nanoparticles (SNPs) in different concentrations: 10 ppm, 20 ppm, and 30 ppm. The crystals’ names and abbreviations are: glycine–copper sulphate (GCS), glycine–copper sulphate doped by 10 ppm SNPs (GCSN1), glycine–copper sulphate doped by 20 ppm SNPs (GCSN2), and glycine–copper sulphate doped by 30 ppm SNPs (GCSN3). Dopant silver nanoparticles increased: crystallinity reflecting purity, transparency to UV-Vis. electromagnetic radiation, thermal stability, and melting point of glycine–copper sulphate single crystal. GCSN3 is a super conductor. High thermal conductivity of crystals ranging from 1.1 W·min⁻¹·K⁻¹ to 1.6 W·min⁻¹·K⁻¹ enabled attenuation of electromagnetic radiation and rapid heat dissipation due to good dielectric and polar properties. On rising temperature, AC electrical conductivity and dielectric properties of perfect crystal GCSN3 increased confirmed attenuation of thermal infrared radiation. Full article

The demand of high performance and environmentally sustainable construction materials is ever-increasing in the construction industry worldwide. The rapid growth of nanotechnology and diverse nanomaterials’ accessibility has provided an impulse for the uses of smart construction components like nano-alumina, nano-silica, nano-kaolin, nano-titanium, and so forth Amongst various nanostructures, the core-shell nanoparticles (NPs) have received much interests for wide applications in the field of phase change materials, energy storage, high performance pigments, coating agents, self-cleaning and self-healing systems, etc., due to their distinct properties. Through the fine-tuning of the shells and cores of NP_S, various types of functional materials with tailored properties can be achieved, indicating their great potential for the construction applications. In this perception, this paper overviewed the past, present and future of core-shell NPs-based materials that are viable for the construction sectors. In addition, several other applications of the core-shell NPs in the construction industries are emphasized and discussed. Considerable benefits of the core-shell NPs for pigments, phase change components, polymer composites, and self-cleaning glasses with enhanced properties are also underlined. Effect of high performance core-shell NPs type, size and content on the construction materials sustainability are highlighted. Full article

The present work reports the preparation of gardenia yellow pigment containing paraffin oil nanoemulsions stabilized by Span80 and Tween80. The preparation of the required nanoemulsions was optimized by testing different conditions, such as varying the hydrophilic–lipophilic balance (HLB), the emulsifier concentration (EC), the oil–water ratio (OWR), and the temperature (T), as determined by the average droplet diameter (ADD) and polydispersity index (PDI). Our results indicated that a minimum ADD of 65.9 nm and PDI of 0.116 were obtained at an optimum HLB value of 6.0, EC of 10% (w/w), OWR of 2:1, and T of 40 °C. Both the steady-state and dynamic rheological parameters were further investigated, revealing that the emulsions exhibited pseudoplastic behaviors. The long-term stabilities of the nanoemulsions after the addition of inorganic salts were monitored by observing their visual appearances. It was found that the emulsions containing pure water or 0.1 M CaCl₂ and AlCl₃ became slightly separated, while the emulsions containing 0.1 M KCl and NaCl showed no separation after 30 days of storage at room T. This difference among different salts could be related to the number of valence electrons of their cations. The spatial electrostatic effects of the monovalent cationic (KCl and NaCl) and the nonionic surfactants were greater than the delamination/sedimentation forces of the system, which was better than the salt based on the cations with valences greater than one (CaCl₂ and AlCl₃). In conclusion, the present work illustrated the formation, rheological properties, and stability of water containing gardenia yellow pigment in paraffin oil nanoemulsions, which can be of great significance for the application of gardenia-yellow-pigment-based formulations. Full article

Extracellular vesicles (EVs) are important mediators of intercellular communication in several physiopathological conditions. Oxidative stress alters EVs release and cargo composition depending on the cell type and stimulus. Recently, most of the EVs studies have focused on the characterization of their cargo, rather than on the morphological features (i.e., size distribution, shape, and localization on the cell surface). Due to their high heterogeneity, to fully characterize EVs both the functional and morphological characterization are required. Atomic force microscopy (AFM), introduced for cell morphological studies at the nanoscale, represents a promising method to characterize in detail EVs morphology, dynamics along the cell surface, and its variations reflecting the cell physiological status. In the present study, untreated or H₂O₂-treated wild-type and SOD1-G93A SH-SY5Y cells have been compared performing a transmission electron microscopy (TEM) and AFM morpho-quantitative analysis of budding and released vesicles. Intriguingly, our analysis revealed a differential EVs profiling, with an opposite behavior and implying different cell areas between WT and SOD1-G93A cells, on both physiological conditions and after H₂O₂ exposure. Our results empower the relationship between the morphological features and functional role, further proving the efficacy of EM/AFM in giving an overview of the cell physiology related to EVs trafficking. Full article

MoP is a topological semimetal which has drawn attention due to its unique electrical and optical properties resulting from massless electrons. In order to utilize these properties for practical applications, it is necessary to develop a technique to produce high-quality, large-scale thin films of this 2D material. We report below our initial results of growth of MoP thin films using atomic layer deposition (ALD), where the film grows layer-by-layer. These films were grown on 5 cm × 5 cm silicon oxide coated Si wafers. Resistivity versus temperature measurements show that these films are metallic and includes a partial superconducting phase. The magnetoresistances of both the longitudinal and Hall currents measured at 1.8 K show a strong effect of the magnetic field on the resistivity. Density functional theory was employed to determine the lattice constants of the MoP crystal. These parameters were in good agreement with those obtained from the Rietveld fit to the XRD spectrum of the films. Full article

Carbon-coating proved an efficient and reliable strategy to increase the power capabilities and lifetime of phosphate-based positive electrode materials for Li-ion batteries. In this work, we provide a systematic study on the influence of polyacrylonitrile-(PAN)-derived carbon coating on electrochemical properties of the nanosized Li-rich Li_1+δ(Fe_0.5Mn_0.5)_1−δPO₄ (Li-rich LFMP) cathode material, as well as the characterization of carbon-coated composites by means of Raman spectroscopy for the determination of carbon graphitization degree, DF-STEM and STEM-EELS for the estimation of carbon layer thickness, uniformity and compositional homogeneity of the conductive layer respectively, and impedance spectroscopy for the determination of charge transfer resistances of the resulted composite electrodes in Li-based cells. Using PAN as a carbon coating precursor enables significantly enhancing the cycling stability of Li-rich LFMP/C compared to those conventionally obtained with the glucose precursor: up to 40% at high current loads of 5–10C retaining about 78 ± 2% of capacity after 1000 cycles. Varying the PAN-derived carbon content in the composites allows controlling the electrochemical response of the material triggering either a high-capacity or a high-power performance. Full article

Bimetallic nanoparticles are a complex nanoscale combination of two metal constituents. The superior properties of bimetallic nanoparticles (BNPs) compared with monometallic nanoparticles have attracted much attention from both scientific and technological perspectives. In recent years, many fabrication techniques have been proposed, and the detailed characterization of bimetallic nanoparticles has been made possible by the rapid advancement of nanomaterial analysis techniques. Metallic nanoparticles can be classified according to their origin, size, and structure, and their synthesis process can be physical, chemical, or biological. Bimetallic nanoparticles are more attractive than metal nanoparticles due to their unique mixing patterns and synergistic effects of two metal nanoparticles forming the bimetal. In this review, the different bimetallic synthesis methods and various characterization techniques are discussed. The paper will also discuss various applications for bimetallic nanoparticles. Different characterization techniques for bimetallic nanoparticles include X-ray diffraction (XRD) to investigate crystallinity and phase composition; the morphology and composition analysis of nanoparticles are studied using a scanning electron microscope fitted with an energy-dispersive X-ray analyzer (EDX); transmission electron microscopy (TEM), UV–vis spectrum, FTIR, and TGA analysis are also among the characterization tools used. Finally, we report on the various applications of BNPs, which include antimicrobial activity, pollutant removal, and wastewater application. Full article

Due to their biocompatibility, ease of surface modification, and heating capabilities, gold nanomaterials are considered excellent candidates for the advancement of photothermal therapy techniques and related applications in cancer treatment. Various morphologies of gold nanomaterials have been shown to heat when exposed to high-powered laser irradiation, especially that which is from the near-infrared (NIR) region. While these lasers work well and are effective, light-emitting diodes (LEDs) may offer a safe and low-powered alternative to these high energy lasers. We investigated the heating capability of NIR-dye conjugated gold nanorods when exposed to an 808 nm LED light source using polyethylene glycol (PEG)-coated gold nanorods as the control. In this way, since the rods exhibited a surface plasmon resonance peak between 795 and 825 nm for both the PEG-coated rods and the dye-conjugated rods, which are fairly close to the frequency of the 530 mW, 850 nm LED light source, we were able to reveal the heating effect of the dye modification. While both morphologies heat when irradiated with the LED light, we demonstrated that the addition of an NIR dye increases the rate of heating and cooling, compared to the PEGylated counterpart. To our knowledge, the complementary effect given by the conjugated NIR-dye has not been previously reported in the literature. The targeting abilities of the NIR-dye combined with the increased heating rate of the modified particles used in this proof-of-concept work suggests that these particles may be exceptional candidates for theranostic applications. Full article