Field Emission Scanning Electron Microscopy Research Articles

The Production of Hydrochar from Hazelnut Waste and its Use in the Removal of Pb (II) and Cr (III)

Heavy metals (HMs) are causing an increasing amount of harm to the environment and living organisms. A variety of studies is being conducted to eliminate or diminish such pollutants. In this study, hydrochar was produced from hazelnut waste (HW), and Pb and Cr ion removal research was conducted with this adsorbent. In this way, both the evaluation of HW was provided and the removal of HMs, which are very harmful for the environment. The structural and morphological properties of the produced hydrochars were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR), and EDX analyses. The effects of many parameters, such as initial concentration, temperature, adsorbent dosages, contact time, and pH on adsorption were discussed. In the studies executed in different parameter environments, it was determined that hydrochar removed 76% and 67% of Pb and Cr ions, respectively. Also, Langmuir and Freundlich isotherm models, pseudo-first-order and pseudo-second-order kinetic models, and thermodynamic parameters like Gibbs free energy were investigated in order to gain a better understanding of the adsorption system of the generated hydrochar. Furthermore, the hydrochar's reusability as an adsorbent was investigated, and it was demonstrated that the material continued to function effectively even after four cycles.

Investigation and evaluation of palygorskite microstructure following acid pretreatment and its potential use as an adsorbent for copper

Palygorskite exhibits distinctive morphological and textural characteristics due to its fibrous and micropore nature. This research experimentally investigates the microstructure of palygorskite and how acid treatment changes the fibrous shape and ability to adsorb. Acetic and hydrochloric acid were used to study the effect of acid on palygorskite fibrous morphology. The effect of several factors, including acid type, hydrochloric acid concentration, mixing time, and temperature, on the efficiency of palygorskite in removing Cu was also studied. Different analytical techniques were used: scanning electron microscopy, field emission scanning electron microscopy, X-ray diffraction, X-ray fluorescence, particle size distribution, and zeta potential. Results illustrated that acetic acid effectively dispersed fibre aggregates, creating voids within the fibrous structure and reducing particle size while keeping the shape of the fiber. Hydrochloric acid led to varying degrees of structural changes. A concentration of 0.5, 1, and 2 M dispersed the fibre agglomerates and increased positive surface charge. Formation of an amorphous silica phase at 4 and 6 M, accompanied by a reduction in positive zeta potential. In general, acid pretreatment kept the morphology of the palygorskite fibre; however, 6 M HCl induced microfractures and roughness on the fibre rod. At room temperature and with a mixing time of one hour, the adsorption capacity of raw palygorskite for Cu was 298.4 ppm, while that of acetic acid pretreated palygorskite was 277.2 ppm. The primary decrease in Cu concentration occurred following palygorskite treatment with 0.5 M HCl to 212 ppm.

Crude Oil Desulfurization by Polystyrene/Graphene Nanocomposite Membranes

The main aim of this paper is to evaluate the effect of graphene nanoplatelets (GNPs) on the desulfurization of the polystyrene nanofibers. Hence, different loadings of GNP, 0.5, 1, 1.5, and 2 wt.% GNP was incorporated into the polystyrene nanofibers using electrospinning technique. Several characteristics of the electrospun membranes were investigated. The obtained field emission scanning electron microscopy (FE-SEM) images confirmed the formation of uniform fibers and proper distribution of the particles in the electrospun structures. In addition, thinner fibers with smaller pore sizes were formed by addition of the GNPs into the nanofibrous mats. Moreover, the hydrophobic behavior reduced by increment of GNP content in the polystyrene nanofibers. Fourier transform infrared spectra (FTIR) confirmed the interaction of the polymer chains with the loaded filler particles. Furthermore, introduction of the GNP nanofillers in the decrease of the crude oil sulfur content from 2.8% to 2.6% via addition of 0.5 wt.% of GNPs into the as-spun fibers. Further reduction of the sulfur content (to 1.8%) was also obtained by embedding 2 wt.% of GNPs. Overall, the obtained data manifested that the electrospinning composite membranes are good candidate material for removing sulfur from crude oil.

Anticorrosion properties of ionic liquid functionalized graphene oxide epoxy composite coating on the carbon steel for CCUS environment.

The adoption of carbon capture, utilization, and storage (CCUS) technology is increasingly prevalent, driven by the global initiative to conserve energy and reduce emissions. Nevertheless, CCUS has the potential to induce corrosion in equipment, particularly in high-pressure environments containing carbon dioxide (CO2). Therefore, anti-corrosion protection is necessary for the metal utilized for CO2 production and storage equipment. Herein, an ionic liquid (triethylsulfonium bis-trifluoromethylsulfonyl-imide) was used to functionalize graphene oxide (prepared via the improved Hummers method). Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) confirmed ionic liquids (IL) were successfully attached to the graphene oxide (GO) lattice. Afterwards, 0.5 wt% and 1 wt% IL-GO composites were separately incorporated into the epoxy and coated on the carbon steel substrate with a thickness of 50 ± 2µm. The surface examinations demonstrated a consistent distribution of the ILGO composite in the epoxy matrix and achieved a uniform surface. The anti-corrosive properties of 0.5 wt% and 1 wt% IL-GO/epoxy coatings were evaluated using electrochemical tests such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) after immersion in the CO2 (1.5MPa) and 3.5 wt% sodium chloride (NaCl) systems. After 48h of immersion in a corrosion environment (CO2-NaCl), the protection efficiency of 0.5 wt% and 1 wt% IL-GO/epoxy coatings is 86.41 ± 0.55 and 92.59 ± 0.83 (%), respectively. The findings of this study demonstrated that the ILGO composite-reinforced epoxy coating exhibited exceptional corrosion resistance when exposed to CO2.

Exploring Green Pyrotechnic Formulations and Primary Explosives with 1,3,4-Oxadiazole-Based Micro and Submicron Energetic Coordination Polymers.

Alkali and alkaline-earth metal incorporated 5,5'-dinitramino-3,3'-azo-1,3,4-oxadiazole (H2DNAO) based Energetic Coordination Polymers (ECPs), namely dipotassium 5,5'-dinitramino-3,3'-azo-1,3,4-oxadiazole(K2DNAO), dicesium 5,5'-dinitramino-3,3'-azo-1,3,4-oxadiazole(Cs2DNAO) and barium 5,5'-dinitramino-3,3'-azo-1,3,4-oxadiazole(BaDNAO) are synthesized for the first time. Synthesized ECPs are thoroughly characterized using infrared spectroscopy (IR), elemental analysis (EA), thermogravimetric analysis and differential scanning calorimetry (TGA-DSC), field emission scanning electron microscopy (FE-SEM), and dynamic light scattering (DLS), UV-vis spectroscopy. All ECPs are also confirmed by single-crystal X-ray diffraction technique (SC-XRD). The micro-ECPs exhibit excellent densities (1.98-2.80g cm-3), insensitivities (IS: 25-40 J; FS: 240-360 N), and good thermal stabilities (Td: 182-212°C). K2DNAO and Cs2DNAO show good detonation performance (VOD:7460-7893m s-1; DP: 27.5-30.6GPa), respectively. To further investigate sub-micron-energetics, three sub-micron ECPs are prepared from their micro counterparts using ultrasonication method, demonstrating significant improvement in thermal stability (Td: 194-221°C) but are highly sensitivity (IS: 2-15J; FS: 40-360N). Burning tests of two experimental formulations using micro K2DNAO and Cs2DNAO demonstrate their potential in green pyrotechnic applications. Interestingly, the submicron-counterparts show remarkable initiating capability. Considering their ease of synthesis, and safety profile, these materials can be effectively transported in their microform and can be rapidly converted into submicron-form on demand, making them suitable for pyrotechnic applications.

Morphogenesis of Aragonite Biomineral Structures by the Nonclassical Colloidal Crystal Growth Mechanism Revisited on the Nanoscale: The Noah's Ark Shell (Arca noae, L.) Case Study.

Characterization and formation of the biomineral aragonite structures of the Noah's Ark shell (Arca noae L.,1758) were studied from structural, morphogenetic, and biochemical points of view. Structural and morphological features were examined using X-ray diffraction, field-emission scanning electron microscopy, and atomic force microscopy, while thermal properties were determined by thermogravimetric and differential thermal analyses. Proteins from the soluble organic matrix (SOM) were analyzed by Edman degradation. The results showed that the Noah's Ark shell exhibits several distinct biomineral structures characterized by complex morphologies and different forms of aragonite. The inner shell of the Ark is characterized by a combination of nanogranular surfaces and micron-sized, idiomorphically developed aragonite crystals indicative of orthorhombic symmetry. The formation of these structures is discussed in terms of the nonclassical crystal growth route considering the colloidally mediated mechanism based on the initial particle-particle interaction of the nanosized and metastable precursor aragonite phase and their dissolution and recrystallization processes. These structures contained a small amount of connecting organic material, SOM, assessed at 1.5% of the total mass. Edman degradation revealed the partial amino acid sequence that is present also in the tetratricopeptide repeat (TPR) protein 8 from diverse mussels. Bacterial TPR-containing protein was found to be involved in the biomineralization process, so we propose such a function for these proteins also in mussels.

Enhancing Mass Transfer Coefficient Prediction from Field Emission Scanning Electron Microscope Images Through Convolutional Neural Networks and Data Augmentation Techniques

With the growing demand for drug products requiring lyophilization, it is essential to either expand aseptic drying capacity or improve the efficiency of existing capacity through process intensification, ensuring that resources are utilized to their full potential. In this regard, mathematical models are highly recommended to assist professionals in process optimization. To effectively utilise these models, it is also essential to develop robust techniques for determining key parameters, including the product resistance to vapour flow. Traditional experimental methods for evaluating this coefficient are time-intensive and/or require the insertion of probes into the product, which is not feasible at a manufacturing scale. This study addresses these challenges by introducing a novel deep learning framework designed to predict the mass transfer coefficient directly from Field Emission Scanning Electron Microscope images. This approach significantly streamlines the evaluation process, leveraging the high-resolution capabilities of Field Emission Scanning Electron Microscope for detailed analysis. In this work, we focus on advanced Field Emission Scanning Electron Microscope image processing, choice of strategic convolutional neural network configuration, and thorough model performance evaluation to predict the mass transfer coefficient. Given the frequent scarcity of datasets in this field, we have employed data augmentation techniques to enhance the robustness of our model. The results demonstrate good predictive accuracy (error on the interpolation test data lower than 5%), highlighting the potential of this framework to facilitate the assessment of mass transfer coefficients in freeze-dried products.

Mangifera indica–driven CuO nanoparticles: properties for sensing and optoelectronics

This study reports biological synthesis of Mangifera indica leaf extract–mediated copper oxide nanoparticles (CuO NPs). CuO NPs are characterized for crystal structure and crystallite size determination, absorption peak, particle size and morphological analysis, elemental composition, and functional groups’ identification using X-ray diffraction (XRD), ultraviolet–visible spectroscopy, high-resolution transmission electron microscope (HRTEM), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectrometer (EDS), and Fourier transform infrared (FTIR). NPs show an absorption peak ∼338 nm and Tauc’s plot gives band gap energy ∼2.2 eV. XRD pattern depicts monoclinic phase ∼18 nm average crystallite size NPs. FESEM and HRTEM micrographs confirm the needle-shaped NPs having 5:40 nm aspect ratio. The EDS spectrum, depicting the Cu and O peaks, shows that the particles are free from any type of impurity. FTIR analysis elucidates the role of bioactive chemicals in the extract in the successful formation of NPs. The photoluminescence study reveals the existence of violet, green, orange, yellow, and red emission bands. Also, NPs exhibit an electrical conductivity of 1.37 × 10–7 S/m and 5. 31 × 10–7 S/m at 100°C and 200°C. Thus, environmentally friendly, non-toxic, green-synthesized CuO NPs hold significant potential for applications in resistive sensors, solar cells, and optoelectronics devices.

Influence of Ho3+ doping on microstructure and dielectric properties of CaCu3Ti4O12 lead free ceramic

Abstract The present research investigated the effect of Ho3+ doping on the microstructural and dielectric properties of Ca1-xHoxCu3Ti4O12 ceramic. X-ray diffraction (XRD) patterns confirmed the formation of calcium copper titanate (CCTO) ceramic. Field Emission Scanning Electron Microscopy (FESEM) images showed that the grain size of Ca1-xHoxCu3Ti4O12 samples significantly decreased with increasing Ho3+ ion concentration, which consequently reduced the dielectric constant in the doped CaCu3Ti4O12 ceramics. The lowest dielectric losses (tanδ = 0.13 at 323K and 1 kHz) and a dielectric permittivity (ε′ = 8.38 x 103) were observed in the Ca0.98Ho0.02Cu3Ti4O12 ceramic. The dielectric behaviour of the Ca1-xHoxCu3Ti4O12 ceramics was correlated with the Internal Barrier Layer Capacitance (IBLC) model. X-ray photoelectron spectroscopy (XPS) detected the presence of Cu+/Cu2+ and Ti3+/Ti4+ in all synthesized samples, indicating that electron hopping between Cu+ ↔ Cu2+ and Ti3+ ↔ Ti4+ ionic states was the main cause of the formation of semiconducting grains in the synthesized ceramics.

Bio-synthesised nanoparticles employment for eliminating metals from wastewater via implementation of a three level Box-Behnken technique

The objective of the present study is to optimise the removal of metals such as aluminium, zinc, and copper from industrial wastewater using green-synthesised nanoadsorbents. To achieve this, the Box–Behnken experimental design and response surface methodology will be employed. We used inductively coupled plasma mass spectrometry to analyse the metals present in the wastewater. A three-factor, three-stage Box–Behnken design was used to maximise the removal of these metals from aqueous solution. This involved response surface modelling and quadratic programming based on 17 different experimental data from a batch study. The study focused on three independent variables: pH, contact time, and adsorbent amount. The nanoadsorbents were prepared using a combination of Citrus X sinensis peel and Musa Cavendish peel extract, which served as the reducing agents, to produce a combined peel extract-silver nanoparticle product. Field emission scanning electron microscopy imaging and UV–visible spectroscopic analysis unequivocally demonstrated the presence of nanoparticles, with a surface plasmon resonance at 438 nm. The optimal values of the selected variables were determined by solving the quadratic regression model and analysing the contour plots of the reaction surface. At the experimental conditions of pH = 5, contact time = 92.5 min, and adsorbent dosage = 0.1 g/L, the recovery efficiency of Al, Cu, and Zn was significantly reduced. The optimised parameters were successfully applied to wastewater collected, and the degradation of detected metal ions was tested. The experiment demonstrated an effective reduction in these metals.

Biosynthesis of zero-dimensional TiO2 nanostructures for potential photocatalytic applications

This study introduces a sustainable approach to synthesize zero-dimensional TiO2 nanostructures using Allium sativum (garlic) clove extract as a biogenic capping and reducing agent. The synthesized particles were dried at 80 ºC for 24 hours and calcined at 450 ºC for 2 hours. X-ray diffractometer (XRD), Field Emission Scanning Electron Microscopy (FESEM), UV-vis spectroscopy, and photocatalytic activity analysis were used to characterize the synthesized nanoparticles. The XRD pattern revealed the prevalence of the tetragonal anatase phase in the synthesized nanostructures, with an average crystallite size of 6.45 nm. The Williamson-Hall plot method was employed to evaluate the type of strain induced in the synthesized particles, and the crystallinity of TiO2 nanostructures was estimated to be 74.91%. The Rietveld analysis calculated the lattice parameters, cell volume, and other relevant parameters. FESEM image showed spherical nanostructures with an average size of 45.08 nm. UV-vis spectroscopy indicated an optically active region at ~361 nm, and the direct bandgap, calculated using the Tauc plot, was 3.28 eV. The photocatalytic efficiency of TiO2 for methylene blue degradation reached 86.23% within 90 minutes, showing its potential for environmental remediation.

Comprehensive Characterization and Impact Analysis of Interlayers on CO2 Flooding in Low-Permeability Sandstone Reservoirs

In low-permeability sandstone reservoirs (LPSR), impermeable interlayers significantly challenge carbon capture, utilization, and storage (CCUS) and enhance oil recovery (CO2-EOR) processes by creating complex, discontinuous flow units. This study aims to address these challenges through a comprehensive multi-faceted approach integrating geological and microscopic analyses, including core analysis, reservoir petrography, field emission-scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), and well-logging response analysis, and utilizing three-dimensional (3D) geological modeling. The current comprehensive investigation systematically characterizes interlayer types, petrophysical properties, thickness, connectivity, and their spatial distribution in the reservoir unit. Numerical simulations were conducted to assess the sealing efficiency and the impact of various interlayer materials on CO2 flooding over a 10-year period. Results indicate the presence of petrophysical and argillaceous interlayers, with optimal sealing occurring in petrophysical barriers ≥ 4 m and argillaceous barriers ≥ 1.5 m thick. CO2 leakage occurs through preferential pathways that emerge in a side-to-middle and bottom-to-top direction in interbeds, with multidirectional pathways showing greater leakage at the bottom compared to the upper side within barriers. Increased interlayer thickness constraints CO2 breakthrough but reduces vertical flooding area and production ratio compared to homogeneous reservoirs. Augmented interbed thickness and area mitigate CO2 breakthrough time while constraining gravity override and dispersion effects, enhancing horizontal oil displacement. These novel findings provide crucial insights for optimizing CCUS-EOR strategies in LPSR, offering a robust theoretical foundation for future applications and serving as a key reference for CO2 utilization in challenging geological settings of LPSR worldwide.

STUDY THE INFLUENCE OF ANNEALING TEMPERATURE ON THE STRUCTURAL CHARACTERISTICS OF Fe73.5-XCrXCu1Nb3Si13.5B9

Alloy ribbons with the composition Fe73.5-xCrxCu1Nb3Si13.5B9 (where x = 1, 5, 10, 12.5, 17.5) are produced using a rapid quenching technique and subsequently annealed at various temperatures. The development of a homogeneous, ultra-fine grain structure, and also confirmation of the Fe(Si) phase, are examined through X-ray diffraction analysis. As the temperature increases, the amorphous nature of the as-prepared ribbons begins to diminish due to the onset of crystallization nucleation. Differential Scanning Calorimetry (DSC) measurements clearly show that the crystallization temperature shifts to higher values with increasing heating rates and time. A strong correlation between the onset of crystallization and the volume fraction of the crystalline α-Fe(Si) phase is observed through differential thermal scanning calorimetry. Additionally, Field Emission Scanning Electron Microscopy (FESEM) is employed to capture micrographs at different annealing temperatures, reflecting variations in the Cr content. Bangladesh Journal of Physics, Vol. 29, Issue 1, pp. 13 – 24, June 2022

EFFECT OF Cr AS A GRAIN GROWTH INHIBITOR ON CRYSTALLIZATION KINETICS FOR Fe73.5-xCrxCu1Nb3Si13.5B9 (x = 1, 5, 10, 12.5, 17.5)

Nanocrystalline Finemet© alloys of composition Fe73.5-xCrxCu1Nb3Si13.5B9 with x = 1, 5, 10, 12.5, 17.5 were synthesized using the melt spinning technique to study the impact of chromium (Cr) as a grain growth inhibitor on the crystallization kinetics. The alloys were studied under several heat treatments starting from the as-cast to 600℃ and the amorphousity of the ribbons is reduced as well as the nucleation of crystallizations starts. Differential Scanning Calorimetry (DSC) analysis shows that increasing Cr content shifts the crystallization temperatures to higher values, enhancing thermal stability. Moreover, the X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) confirmed the development of an ultra-fine α-Fe(Si) nanocrystalline phase, with the grain size decreasing as Cr content increased. The evolution of microstructure and thermal properties highlight the role of Cr content in delaying crystallization and reducing grain growth, thus improving the nanocrystalline state of the material. These findings provide insights into optimizing Fe-Si-B-based nanocrystalline alloys for advanced applications by balancing thermal treatments and Cr concentration. Bangladesh Journal of Physics, 28(1), 59-68, June 2021

Co-Delivery of Glycyrrhizin and Paclitaxel via Gelatin-Based Core-Shell Nanoparticles Ameliorates 1,2-Dimethylhydrazine-Induced Precancerous Lesions in Colon.

Colorectal cancer is a lethal malignancy that begins from acquired/inherent premalignant lesions. Thus, targeting these lesions at an early stage of the disease could impede the oncogenesis and maximize the efficacy. The present work underscores a combinatorial therapy of paclitaxel (PTX) and glycyrrhizin (GL) delivered via gelatin-derived core-shell nanoparticles [AC-PCL(GL + PTX)-GNPs] for effective management of precancerous lesions. The desolvation method was adopted to prepare GL-loaded gelatin nanoparticles (GL-GNPs), which were coated with PTX and AC-PCL. The prepared NPs exhibited optimal physical attributes and had spherical morphology, as analyzed by transmission electron microscopy and field-emission scanning electron microscopy. In vitro release studies revealed sustained release for ∼96 h. Cell culture studies in HTC 116, and HT-29 cells showed synergistic action with CI < 0.9 and DRI > 1. Moreover, AC-PCL(GL + PTX)-GNPs exhibited amplified intracellular uptake and thus significantly reduced IC50. Pharmacokinetic studies revealed substantiated pharmacokinetic parameters (AUC0-∞, Cmax, etc.). In vivo studies in a 1,2-dimethyl hydrazine-induced model revealed a decrease in the number of lesions, mucin depletion, and subside infiltrations. An immunohistochemical study revealed elevated expression of caspase-9 and suppressed expression of VEGF and Ki-67. Toxicity studies showed insignificant changes in systemic biomarkers along with no alterations in organ morphology and hemocompatibility. In essence, AC-PCL(GL + PTX)-GNPs render a competent and safer tactic to regulate early-stage precancerous lesions.

Magnetic nanoparticles of Nd2Fe14B prepared by ethanol-assisted wet ball milling technique

The magnetic material Nd2Fe14B is one of the strongest magnetic materials found in nature. The demand for the production of these nanoparticles is significantly high due to their exceptional properties. The aim of the present study is to synthesize magnetic nanoparticles of Nd2Fe14B using ethanol in the wet ball milling technique (WBMT). Nd2Fe14B powder an average particle size(APS) of 730 nm was subjected to wet ball milling in stainless steel cup containing 5 mm diameter steel balls.The powder was milled for 12 h at 400 rpm, with intervals of 15 min and a 15-second pause each time. The morphology of the powder and nanoparticles, crystallinity, changes of the samples under temperature, magnetic properties, and the structural bonds were analyzed using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), and Fourier-transform infrared spectroscopy (FTIR).The microstructural images revealed that the shape of the particles changed from flat(730 nm) to spherical(76 nm) after WBMT. The crystallinity results indicated a hexagonal crystal structure, with the average crystallite size being 17.1 nm. In the spectrum of the synthesized Nd2Fe14B nanoparticles, a peak appeared at a wavenumber of 803 cm−1, along with peaks at wavenumbers of 1037 cm−1 and 1083 cm−1, which are associated with the stretching vibrations of Nd-Fe, Fe-B, and Nd-B bonds, respectively. Numerical results of magnetic performance parameters indicated the ferromagnetic properties of the particles(HC = 6097.47, Mr = 34.65 and MS = 49.11).It appears that in WBMT, the operational parameters significantly affect the average crystallite size, saturation magnetization, as well as the size and shape of the nanoparticles. Additionally, the ferromagnetic nature of Nd2Fe14B in the hysteresis loop plays an important role in the thermal stability of the nanoparticles.

Characterization, Antibacterial Activity, and Dye Removal Capacity of Green and Hydrothermal Green Synthesized ZnO Nanostructures Using Crataegus Orientalis

AbstractIn this study, the cost‐effective and environmentally friendly green synthesis of zinc oxide (ZnO) nanostructures is reported using Crataegus orientalis fruit extract with green synthesis (GS) and hydrothermal‐assisted green synthesis (HTGS) methods. The optical, structural, and morphological characteristics of the synthesized ZnO nanostructures are examined by UV–vis Spectroscopy (UV–vis), X‐ray diffraction (XRD), and field emission scanning electron microscopy (FE‐SEM) supported with energy dispersive X‐ray spectroscopy (EDX). XRD patterns confirmed that the synthesized ZnO nanostructures have a hexagonal single phase. The average crystallite size and optical bandgap values are obtained as 31 and 27 nm, 2.8 and 3.02 eV, for GS‐ZnO and HTGS‐ZnO nanostructures, respectively. The synthesized HTGS‐ZnO and GS‐ZnO nanostructures are used as a catalyst in the photodegradation of methylene blue (MB) dye and show excellent degradation activity of 99% after 120 min of UV illumination. In addition, it is found that HTGS‐ZnO and GS‐ZnO nanostructures have a higher antibacterial effect against Staphylococcus aureus ATCC 25923 than ZnO nanostructures synthesized by chemical methods. Moreover, since both synthesis methods show similar results, the GS method, which is lower cost, simpler, and less time‐consuming than the HTGS technique, can be recommended to synthesize ZnO nanostructures using Crataegus orientalis.

Versatile applications of cobalt and copper complexes of biopolymeric Schiff base ligands derived from chitosan.

In the present study, biopolymeric Schiff base (SB) ligands were synthesized from chitosan and isatin. Consequently, their earth abundant transition metal complexes of cobalt and copper were synthesized. All compounds were extensively characterized using FTIR and UV spectroscopy, thermo-gravimetric (TG) analysis, X-ray powder diffraction (XRD) and FESEM (field emission scanning electron microscopy). The impetus of this study was to explore different applications of the same transition metal complexes, thereby converting them to broad spectrum antimicrobial drugs and to useful chemical catalysts. Thus, these cobalt and copper complexes were applied as anti-bacterial and anti-fungal agents and in reductive degradation of common pollutants. Specifically, chitosan, and all synthesized compounds were investigated against fungal species, namely, Candida and Aspergillus, and bacterial species, like Pseudomonas syringae, Escherichia coli, Staphylococcus aureus and Staphylococcus epidermis. All compounds demonstrated promising antimicrobial activity. Chitosan-modified compounds demonstrated a high antifungal activity against Candida albicans and possessed superior antibacterial action than free chitosan. Additionally, catalytic ability in reductive degradation of common dyes, methylene blue (MEB), Congo red (CR) and methyl orange (MO), was investigated. These dyes were conveniently degraded in presence of metal complexes, whereas neither chitosan nor the Schiff base ligand derived from it could carry out similar reaction.

Electrochemical sensor based on multi-walled carbon nanotubes and two-dimensional zeolitic imidazolate framework nanosheets: Application in determining dacarbazine

Background and Purpose: Cancer is a serious public health concern, hence the determination of dacarbazine as a significant chemotherapeutic agent is very important. Experimental Approach: In the present work, we describe using a facile method to synthesize a nanocomposite of multi-walled carbon nanotubes (MWCNTs) and two-dimensional zeolitic imidazolate framework nanosheets (2D ZIF-L NSs). The resulting MWCNTs/2D ZIF-L NSs nanocomposite was characterized by field-emission scanning electron microscopy. The MWCNTs/2D ZIF-L NSs nanocomposite was subsequently used to modify a screen-printed carbon electrode (SPCE) to achieve an electrochemical sensing platform for the detection of dacarbazine. Conclusion: This detection method can be used as a valuable tool in the analysis of pharmaceutical formulations to bring benefits in the cancer treatment.

Study on the Antibacterial Properties and Optical Characteristics of Clear Orthodontic Aligners Coated With Zinc Oxide and Magnesium Oxide Nanoparticles.

This study aimed to evaluate and compare the antibacterial properties and optical characteristics of clear orthodontic aligners coated with zinc oxide (ZnO) and magnesium oxide (MgO) nanoparticles. In this experimental laboratory study, polyethylene terephthalate glycol (PETG) aligner samples were coated with nanoparticles of ZnO, MgO and a combination of both (ZnO + MgO). The surface coatings were analysed before and after stability testing using field emission scanning electron microscopy (FESEM). Colour changes and translucency were measured using a spectrophotometer, and the antimicrobial and antibiofilm properties were evaluated against Streptococcus mutans and Lactobacillus species. Statistical analysis was conducted using SPSS, with significance set at p < 0.05. Significant statistical differences were found in the colour changes between the groups (p < 0.001), with the greatest change in MgO-coated aligners (0.94 ± 0.09), followed by ZnO + MgO (0.75 ± 0.05) and ZnO (0.5 ± 0.09). ZnO-coated aligners exhibited the highest translucency (47.6 ± 0.44) compared to MgO (45.07 ± 0.74) and ZnO + MgO (45.76 ± 0.7) (p = 0.002 and p = 0.026, respectively). Nanoparticle-coated aligners showed significantly reduced bacterial growth (p < 0.05). The ZnO + MgO combination demonstrated superior antibacterial effects compared to individual coatings. Nanoparticles remained stable after 24-h agitation in artificial saliva and brushing, maintaining 60%-65% stability. The aligners coated with ZnO nanoparticles exhibited the least colour change and the highest translucency compared to those coated with MgO nanoparticles and the ZnO + MgO combination. The highest antibacterial properties were observed in the aligners coated with a combination of ZnO and MgO nanoparticles.