Search Results (3,153)

This study reports the synthesis and evaluation of iron molybdate (Fe₂(MoO₄)₃) and iron tungstate (FeWO₄) as photocatalysts for the degradation of a real industrial effluent from aluminum anodizing processes under visible light irradiation. The oxides were synthesized via a co-precipitation method in an aqueous medium, followed by microwave-assisted hydrothermal treatment. Structural and morphological characterizations were performed using X-ray diffraction, field-emission scanning electron microscopy, Raman spectroscopy, ultraviolet–visible (UV–vis), and photoluminescence (PL) spectroscopies. The effluent was characterized by means of ionic chromatography, total organic carbon (TOC) analysis, physicochemical parameters (pH and conductivity), and UV–vis spectroscopy. Both materials exhibited well-crystallized structures with distinct morphologies: Fe₂(MoO₄)₃ presented well-defined exposed (001) and (110) surfaces, while FeWO₄ showed a highly porous, fluffy texture with irregularly shaped particles. In addition to morphology, both materials exhibited narrow bandgaps—2.11 eV for Fe₂(MoO₄)₃ and 2.03 eV for FeWO₄. PL analysis revealed deep defects in Fe₂(MoO₄)₃ and shallow defects in FeWO₄, which can influence the generation and lifetime of reactive oxygen species. These combined structural, electronic, and morphological features significantly affected their photocatalytic performance. TOC measurements revealed degradation efficiencies of 32.2% for Fe₂(MoO₄)₃ and 45.3% for FeWO₄ after 120 min of irradiation. The results highlight the critical role of morphology, optical properties, and defect structures in governing photocatalytic activity and reinforce the potential of these simple iron-based oxides for real wastewater treatment applications. Full article

Plasma-activated water (PAW), enriched with reactive oxygen and nitrogen species (RONS), presents oxidative and antimicrobial characteristics with potential in cosmetic applications. This study examined the effects of two PAW formulations—nitrate-rich (PAW-N) and peroxide-rich (PAW-P)—on human hair types classified as straight (Type 1), wavy (Type 2), and coily/kinky (Type 4). The impact of PAW on hair structure and chemistry was evaluated using Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), UV–Vis spectrophotometry, and physicochemical analyses of the liquids (pH, ORP, conductivity, and TDS). PAW-N, with high nitrate content (~500 mg/L), low pH (2.15), and elevated conductivity (6244 µS/cm), induced significant damage to porous hair types, including disulfide bond cleavage, protein oxidation, and lipid degradation, as indicated by FTIR and EDS data. SEM confirmed severe cuticle disruption. In contrast, PAW-P, containing >25 mg/L of hydrogen peroxide and exhibiting milder acidity and lower ionic strength, caused more localized and controlled oxidation with minimal morphological damage. Straight hair showed greater resistance to both treatments, while coily and wavy hair were more susceptible, particularly to PAW-N. These findings suggest that the formulation and ionic profile of PAW should be matched to hair porosity for safe oxidative treatments, supporting the use of PAW-P as a gentler alternative in hair care technologies. Full article

Sorption and advanced oxidative processes (AOPs) are potential strategies for the removal of organic compounds, such as caffeine, from aqueous media. Such strategies tend to be more promising when combined with biopolymeric membranes as sorbents and photocatalyst supports. Therefore, the aim of the present study was to investigate sorption and AOP parameters in the performance of chitosan membranes and chitosan/TiO₂ composite membranes in individual and hybrid systems involving the photolysis, photocatalysis, and sorption of caffeine. Caffeine degradation by photolysis was 19.51 ± 1.14, 28.61 ± 0.05, and 30.64 ± 6.32%, whereas caffeine degradation by photocatalysis with catalytic membrane was 18.33 ± 2.20, 20.83 ± 1.49, and 31.41 ± 3.08% at pH 6, 7, and 8, respectively. In contrast, photocatalysis with the dispersed catalyst achieved degradation of 93.56 ± 2.12, 36.42 ± 2.59, and 31.41 ± 1.07% at pH 6, 7, and 8, respectively. These results indicate that ions present in the buffer solutions affect the net electrical charge on the surface of the composite biomaterial with the change in pH variation, occupying active sorption sites in the structure of the biomaterial, which was characterized by Fourier transform infrared spectrometry, thermogravimetric analysis, differential scanning thermogravimetry, and X-ray diffraction. Thus, it is verified that in a combined process of caffeine removal under UV irradiation and use of chitosan/TiO₂ composite membranes in phosphate-buffered medium, the photolysis mechanism is predominant, with little or no contribution from sorption, and that the TiO₂ catalyst promotes a significant reduction in the percentage of pollutant in the medium only when used dispersed and at low pH. Full article

Volcanic rock is a natural mineral material which has garnered interest for its potential application in water treatment due to its unique physicochemical properties. In this study, we prepared a polysilicate aluminum chloride (PSAC) coagulant using volcanic rock which exhibited good coagulation–flocculation performance. Further investigation into the influence of synthetic parameters, such as calcination temperature, reaction time, and alkali types, on the structure and performance of a volcanic rock-derived coagulant was conducted. Techniques including Scanning Electron Microscopy, Energy-Dispersive Spectroscopy, Fourier-Transform Infrared Spectroscopy, and X-Ray Diffraction were utilized to characterize it. Also, a ferron-complexation timed spectrophotometric method was used to study the distribution of aluminum species in the coagulant. Results indicated that the volcanic rock that was treated with acidic and alkaline solutions had the potential to form PSAC with Al-OH, Al-O-Si, Fe-OH, and Fe-O-Si bonds, which influenced the coagulation–flocculation efficiency. An acid leaching temperature of 90 °C, 8 mL of 2 mol/L NaOH, a reaction time of 0.5 h, and a reaction temperature of 60 °C were conducive to the preparation. A higher temperature could result in a higher proportion of Alb species, and, at 100 °C, the Ala, Alc, and Alb were 29%, 24%, and 47%, respectively, achieving a residual turbidity lower than 1 NTU at an appropriate dosage, as well as a reduction of over 0.1 to 0.018 in the level of UV₂₅₄. The findings of this study provide a feasible method to prepare a flocculant using volcanic rock. Further application is expected to yield good results in wastewater/water treatment. Full article

Background/Objectives: Magnetic iron oxide nanoparticles (IONPs), human serum albumin (HSA) and folic acid (FA) are prospective components for hybrid nanosystems for various biomedical applications. The magnetic nanosystems FA-HSA@IONPs (FAMs) containing IONPs, HSA, and FA residue are engineered in the study. Methods: Composition, stability and integrity of the coating, and peroxidase-like activity of FAMs are characterized using UV/Vis spectrophotometry (colorimetric test using o-phenylenediamine (OPD), Bradford protein assay, etc.), spectrofluorimetry, dynamic light scattering (DLS) and electron magnetic resonance (EMR). The selectivity of the FAMs accumulation in cancer cells is analyzed using flow cytometry and confocal laser scanning microscopy. Results: FAMs (d_N~55 nm by DLS) as a drug delivery platform have been administered to cancer cells (human breast adenocarcinoma MCF-7 and MDA-MB-231 cell lines) in vitro. Methylene blue, as a model photosensitizer, has been non-covalently bound to FAMs. An increase in photoinduced cytotoxicity has been found upon excitation of the photosensitizer bound to the coating of FAMs compared to the single photosensitizer at equivalent concentrations. The suitability of the nanosystems for photodynamic therapy has been confirmed. Conclusions: FAMs are able to effectively enter cells with increased folate receptor expression and thus allow antitumor photosensitizers to be delivered to cells without any loss of their in vitro photodynamic efficiency. Therapeutic and diagnostic applications of FAMs in oncology are discussed. Full article

In this work, we report a novel mechanochemical synthesis method for the synthesis of quinoxaline derivatives—a spiral gas–solid two-phase flow approach, which enables the efficient preparation of quinoxaline compounds. Compared to conventional synthetic methods, this approach eliminates the need for heating or solvents while significantly reducing reaction time. The structures of the synthesized compounds were characterized using nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible (UV–Vis) absorption spectroscopy, powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and high-performance liquid chromatography (HPLC). Using the synthesis of 2,3-diphenylquinoxaline (1) as a model reaction, the synthetic process was investigated with UV–Vis spectroscopy. The results demonstrate that when the total feed amount was 2 g with a carrier gas pressure of 0.8 MPa, the reaction completed within 2 min, achieving a yield of 93%. Furthermore, kinetic analysis of the reaction mechanism was performed by monitoring the UV–Vis spectra of the products at different time intervals. The results indicate that the synthesis of 1 follows the A4 kinetic model, which describes a two-dimensional diffusion-controlled product growth process following decelerated nucleation. Full article

This study developed phospholipid-based liposomes loaded with extract from wild thyme (Thymus serpyllum L.) tea processing residues to enhance polyphenol stability and delivery. Liposomes were prepared with phospholipids alone or combined with 10–30 mol% cholesterol or β-sitosterol. The effect of different lipid compositions on encapsulation efficiency (EE), particle size, polydispersity index (PDI), zeta potential, stability, thermal properties, diffusion coefficient, and diffusion resistance of the liposomes was investigated. Liposomes with 10 mol% sterols (either cholesterol or β-sitosterol) exhibited the highest EE of polyphenols, while increasing sterol content to 30 mol% resulted in decreased EE. Particle size and PDI increased with sterol content, while liposomes prepared without sterols showed the smallest vesicle size. Encapsulation of the extract led to smaller liposomal diameters and slight increases in PDI values. Zeta potential measurements revealed that sterol incorporation enhanced the surface charge and stability of liposomes, with β-sitosterol showing the most pronounced effect. Stability testing demonstrated minimal changes in size, PDI, and zeta potential during storage. UV irradiation and lyophilization processes did not cause significant polyphenol leakage, although lyophilization slightly increased particle size and PDI. Differential scanning calorimetry revealed that polyphenols and sterols modified the lipid membrane transitions, indicating interactions between extract components and the liposomal bilayer. FT-IR spectra confirmed successful integration of the extract into the liposomes, while UV exposure did not significantly alter the spectral features. Thiobarbituric acid reactive substances (TBARS) assay demonstrated the extract’s efficacy in mitigating lipid peroxidation under UV-induced oxidative stress. In contrast, liposomes enriched with sterols showed enhanced peroxidation. Polyphenol diffusion studies showed that encapsulation significantly delayed release, particularly in sterol-containing liposomes. Release assays in simulated gastric and intestinal fluids confirmed controlled, pH-dependent polyphenol delivery, with slightly better retention in β-sitosterol-enriched systems. These findings support the use of β-sitosterol- and cholesterol-enriched liposomes as stable carriers for polyphenolic compounds from wild thyme extract, as bioactive antioxidants, for food and nutraceutical applications. Full article

100 nm thick TiO₂/TiN bilayers with varying thickness ratios were deposited via reactive sputtering of a Ti target in controlled oxygen and nitrogen atmospheres. Post-deposition annealing in air at 600 °C was performed to induce nitrogen diffusion through the oxygen-deficient TiO₂ layer. The resulting changes in morphology and chemical environment were investigated in detail using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy. Detailed TEM and XPS analyses have confirmed nitrogen diffusion across the TiO₂ layer, with surface nitrogen concentration and the ratio of interstitial to substitutional nitrogen dependent on the TiO₂/TiN mass ratio. Optical studies demonstrated modifications in optical constants and a reduction of the effective bandgap from 3.2 eV to 2.6 eV due to new energy states introduced by nitrogen doping. Changes in surface free energy induced by nitrogen incorporation showed a correlation to nitrogen doping sites on the surface, which had positive effects on overall photocatalytic activity. Photocatalytic activity, assessed through methylene blue degradation, showed enhancement attributed to nitrogen doping. Additionally, deposition of a 5 nm gold layer on the annealed sample enabled investigation of synergistic effects between nitrogen doping and gold incorporation, resulting in further improved photocatalytic performance. These findings establish the TiO₂/TiN bilayer as a versatile platform for supporting thin gold films with enhanced photocatalytic properties. Full article

In this study, lanthanum–nitrogen co-doped titanium dioxide (La-N-TiO₂) thin films were fabricated using Ion Beam Assisted Deposition (IBAD) and subjected to accelerated ultraviolet (UV) aging experiments to systematically investigate the impact of co-doping on the films’ resistance to UV aging. X-ray diffraction (XRD) analysis revealed that La-N co-doping inhibits the phase transition from anatase to rutile, significantly enhancing the phase stability of the films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) characterizations indicated that co-doping increased the density and surface uniformity of the films, thereby delaying the expansion of cracks and increase in roughness induced by UV exposure. Energy-dispersive X-ray spectroscopy (EDS) results confirmed the successful incorporation of La and N into the TiO₂ lattice, enhancing the chemical stability of the films. Contact angle tests demonstrated that La-N co-doping markedly improved the hydrophobicity of the films, inhibiting the rapid decay of hydrophilicity during UV aging. After three years of UV aging, the co-doped films maintained high structural integrity and photocatalytic performance, exhibiting excellent resistance to UV aging. These findings offer new insights into the long-term stability of photovoltaic self-cleaning materials. Full article

This study investigates the antioxidant, antimicrobial, and antitumor activities of Taraxacum officinale (Dandelion) and Artemisia annua (Sweet Wormwood) extracts, along with their role in the green synthesis of gold (AuNPs) and silver nanoparticles (AgNPs). Bioreduction was achieved using aqueous and ethanolic extracts (100 mg/mL), enabling solvent-dependent comparisons. Nanoparticles were characterized using ultraviolet–visible spectroscopy (UV–Vis), fluorescence spectroscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS), high-resolution transmission electron microscopy (HRTEM), and zeta potential analysis. Each technique revealed complementary aspects of nanoparticle morphology, size, and stability, with UV–Vis indicating aggregation states and DLS confirming solvent-related size variation even at 3–5% ethanol. Gold nanoparticles synthesized from Dandelion showed strong antibacterial activity against Staphylococcus aureus, while silver nanoparticles from both plants were effective against Escherichia coli. Cytotoxicity assays indicated that silver nanoparticles obtained from ethanolic Dandelion extract containing 3% ethanol in aqueous solution (AgNPsE_ETOH3%-D) significantly reduced LoVo (p = 4.58 × 10⁻³) and MDA-MB-231 (p = 7.20 × 10⁻⁵) cell viability, with high selectivity indices (SI), suggesting low toxicity toward normal cells. Gold nanoparticles synthesized from aqueous Dandelion extract (AuNPsEaq-D) also showed favorable SI values (2.16 for LoVo and 8.41 for MDA-MB-231). Although some formulations demonstrated lower selectivity (SI < 1.5), the findings support the therapeutic potential of these biogenic nanoparticles. Further in vivo studies and pharmacokinetic evaluations are required to validate their clinical applicability. Full article

Biosynthesized ZnO nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible (UV-vis) spectroscopy, and Fourier transform–infrared (FT-IR) spectroscopy. XRD confirmed a hexagonal wurtzite phase with an average crystallite size of 36.44 nm, while UV-vis spectroscopy showed a distinct absorption peak at 321 nm. The Zeta potential of the ZnO nanostructures was −24.28 mV, indicating high stability in suspension, which is essential for their dispersion and functionality in biological and environmental applications. The nematicidal activity of ZnO was evaluated in vitro at concentrations of 150, 300, 450, and 600 ppm, with the highest concentration achieving 75.71% mortality of second-stage juveniles (J2s) after 72 h. The calculated LC₅₀ values for the treatments were 270.33 ppm at 72 h. Additionally, molecular docking studies indicated significant interactions between the ZnO nanostructures and nematode proteins, HSP-90 and ODR1, supporting their potential nematicidal mechanism. This research highlights the effectiveness of neem leaf extract-mediated ZnO nanostructures as an eco-friendly, sustainable alternative for nematode control, presenting a promising solution for agricultural pest management. Full article

In this work, we report a green synthesis of zinc oxide (ZnO) nanoparticles using aqueous and ethanolic extracts of Tradescantia spathacea (purple maguey) as bioreducing and stabilizing agents, which are plant extracts not previously employed for metal oxide nanoparticle synthesis. This method provides an efficient, eco-friendly, and reproducible route to obtain ZnO nanoparticles, while minimizing environmental impact compared to conventional chemical approaches. The extracts were prepared following a standardized protocol, and their phytochemical profiles, including total phenolics, flavonoids, and antioxidant capacity, were quantified via UV-Vis spectroscopy to confirm their reducing potential. ZnO nanoparticles were synthesized using zinc acetate dihydrate as a precursor, with variations in pH and precursor concentration in both aqueous and ethanolic media. UV-Vis spectroscopy confirmed nanoparticle formation, while X-ray diffraction (XRD) revealed a hexagonal wurtzite structure with preferential (101) orientation and lattice parameters a = b = 3.244 Å, c = 5.197 Å. Scanning electron microscopy (SEM) showed agglomerated morphologies, and Fourier transform infrared spectroscopy (FTIR) confirmed the presence of phytochemicals such as quercetin, kaempferol, saponins, and terpenes, along with Zn–O bonding, indicating surface functionalization. Zeta potential measurements showed improved dispersion under alkaline conditions, particularly with ethanolic extracts. This study presents a sustainable synthesis strategy with tunable parameters, highlighting the critical influence of precursor concentration and solvent environment on ZnO nanoparticle formation. Notably, aqueous extracts promote ZnO synthesis at low precursor concentrations, while alkaline conditions are essential when using ethanolic extracts. Compared to other green synthesis methods, this strategy offers control and reproducibility and employs a non-toxic, underexplored plant source rich in phytochemicals, potentially enhancing the crystallinity, surface functionality, and application potential of the resulting ZnO nanoparticles. These materials show promise for applications in photocatalysis, in antimicrobial coatings, in UV-blocking formulations, and as functional additives in optoelectronic and environmental remediation technologies. Full article

We present a simple method for customizing the optical characteristics of gold-core, silver-shell (Au@Ag) nanoparticles through controlled morphosynthesis via a seed-mediated chemical reduction approach. By systematically adjusting the concentration of cetyltrimethylammonium chloride (CTAC), we obtained precise control over both the thickness of the Ag shell and the particle shape, transitioning from spherical nanoparticles to distinctly defined nanocubes. Bright field and high-angle annular dark-field scanning transmission electron microscopy (BF-STEM and HAADF-STEM), and energy-dispersive X-ray spectroscopy (EDS) were employed to validate the structural and compositional changes. To link morphology with optical behavior, we utilized the Mie and Maxwell–Garnett theoretical models to simulate the dielectric response of the core–shell nanostructures, showing trends that align with experimental UV-visible absorption spectra. This research presents an easy and adjustable method for modifying the plasmonic properties of Ag@Au nanoparticles by varying their shape and shell, offering opportunities for advanced applications in sensing, photonics, and nanophotonics. Full article

This work explores zinc oxide nanoparticle (ZnO NP) synthesis utilizing leaf extract of the Gaultheria fragrantissima plant that are useful in medicine, environmental remediation, and cosmetics due to their antibacterial activity, photocatalytic efficiency, and UV-blocking characteristics. Traditional synthesis methods involve energy-intensive procedures and hazardous chemicals, posing environmental and human health risks. To overcome these limitations, this research focuses on utilizing G. fragrantissima, rich in bioactive compounds such as phenolics and flavonoids, with the methyl salicylate previously reported in the literature for this species, which helps reduce and stabilize NPs. ZnO NPs were characterized through X-ray diffraction (XRD), UV–visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), and energy-dispersive spectroscopy (EDS). The ZnO NPs were found to have a well-defined crystalline structure, with their average crystallite size measured at around 8.26 nm. ZnO NPs exhibited moderate antimicrobial activity against selected microbial strains. These findings underscore the potential of G. fragrantissima-mediated synthesis as an environmentally sustainable and efficient method for producing ZnO NPs with multifunctional applications. This study provides a greener alternative to conventional synthesis approaches, demonstrating a method that is both eco-friendly and capable of yielding NPss with desirable properties. Full article

Fully printable carbon-based multiporous layered electrode perovskite solar cells (MPLE−PSCs) are close to being commercialized due to their excellent stability, their ability to easily be scaled up, and their amenability to mass production via non-vacuum fabrication processes. To improve their efficiency, it is important that detailed studies of the morphologies of mesoporous electrodes be carried out. In this study, we prepared five types of ZrO₂ spacer layers for MPLE−PSCs, and the morphology of ZrO₂ and device performance were evaluated using a scanning electron microscope, nitrogen adsorption/desorption measurements, electrode resistance measurements, UV-visible light reflectance measurements, and current density–voltage measurements. The results reveal that the adequate specific surface area and pore size distribution of mesoporous ZrO₂ provided high insulation ability when used as spacers between electrodes and light absorbance, resulting in a 10.92% photoelectric conversion efficiency with a 23.22 mA cm⁻² short-circuit current density. This information can serve as a guideline for designing morphologies useful for producing high-efficiency devices. Full article