One-step hydrothermal synthesis of CeVO4/bentonite nanocomposite as a dual-functional photocatalytic adsorbent for the removal of methylene blue from aqueous solutions.

Cerium vanadate/modified bentonite (CeVO4/mbt) nanocomposite with different composition percentages was synthesized through a simple one-step hydrothermal method at 180 ℃, and then its photocatalytic activity was evaluated by decolorizing methylene blue (MB) in an aqueous solution under light exposure. In order to increase the surface area as an important parameter in photocatalytic processes, bentonite was modified by ball mill method. The structural and optical properties of the synthesized composites were determined by XRD, FT-IR, DRS, FESEM, EDS, and BET measurements. XRD and EDS results confirmed the successful synthesis of pure CeVO4. FESEM images and EDS mapping showed a proper distribution of rice-like CeVO4 nanoparticles on bentonite. The removal efficiency of MB with only 0.1 g of CeVO4/mbt nanocomposite in 15 min was about 99%, which is significant compared to neat bentonite and pure CeVO4 with efficiency of 30% and 57%. The mentioned nanocomposite followed the first-order kinetics, had a reaction rate constant equal to 0.1483 min-1, and showed acceptable stability in five consecutive cycles.

Novel PWO/ ZnO heterostructured nanocomposites: Synthesis, characterization, and photocatalytic performance.

Photocatalytic degradation is becoming an increasingly attractive method for addressing environmental remediation challenges. In this work, the novel pure PWO/ZnO and doped PWO: Er/ZnO: Ag heterostructure nanocomposites with premier photocatalytic efficiency were synthesized via a simple co-precipitation method followed by a solvothermal procedure. X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX), and ultraviolet-visible (UV-Vis) absorbance measurements techniques were employed to characterize the structural and optical properties. HRTEM images prove the possibility of intimate contact formation at the pure and doped PWO/ZnO heterostructure nanocomposite interfaces. The photocatalytic performance of the PWO/ZnO heterostructure nanocomposites in the degradation of the methylene blue (MB) and methyl orange (MO) dyes under UVA light was evaluated. The photocatalysts' ability in the mineralization of organic pollutants was confirmed by the TOC test. BET and zeta potential analyses were used to study the dye adsorption mechanisms. Additionally, adsorption isotherms and kinetics have been investigated to describe the adsorption of MB and MO into the samples. The degradation rates of MB with PWO/ZnO and PWO: Er/ZnO: Ag heterostructure nanocomposites were 4.7 and 6.6 times higher than those of PWO and PWO: Er nanoparticles. This rate for MO degradation is 5.2 and 3.5 times higher than that of pure PWO and PWO: Er nanoparticles, respectively. This study outlines an easy method to develop innovative, highly effective heterostructure nanocomposites capable of converting UVA light into photocatalytic performance.

Biosynthesize, physicochemical characterization and biological investigations of chitosan-Ferula gummosa essential oil (CS-FEO) nanocomposite.

The bioavailability, solubility, stability, and evaporation rate of essential oils can all be improved by using appropriate nanocarriers. This study describes the simple biosynthesize, physicochemical, optical, and biological activity of Chitosan-Ferula gummosa essential oil (CS-FEO) nanocomposite. The prepared nanocomposite was evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) mapping, transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), UV-vis and photoluminescence (PL) techniques. The XRD investigation showed that crystallinity indexes of CS-FEO nanocomposite were lower than that of the pure CS and higher than nano-CS. According to SEM/TEM images, a spherical shape with a particle size distribution of around 50-250 nm for nanocomposite was obtained. PL measurement exhibited the addition of FEO caused a strong red emission. GC-MS analysis showed 40 various components in FEO. The antibacterial activity was studied using broth micro-dilution, disc diffusion, colony counts, and well agar diffusion methods against Gram-positive and Gram-negative bacteria. The results revealed that CS-FEO has stronger antibacterial activities than pure CS. It was also observed that the combined use of CS with FEO resulted in synergistic effects against studied bacteria. Obtained results imply that the CS-FEO may provide a new outlook in biomedical applications.

Green synthesis of multifunctional ZnO/chitosan nanocomposite film using wild Mentha pulegium extract for packaging applications.

Following the global corona virus pandemic and environmental contamination caused by chemical plastic packaging, awareness of the need for environmentally friendly biofilms and antibacterial coatings is increasing. In this study, a biodegradable hybrid film, comprising of green-synthesized zinc oxide nanoparticles (ZnO NPs) with a chitosan (CS) matrix, was fabricated using a simple casting procedure. The ZnO NPs were synthesized using wild Mentha pulegium extract, and the synthesized NPs and films were characterized using different approaches. The structural, morphological, mechanical, antibacterial, and optical properties, as well as the hydrophilicity, of the prepared samples were investigated using various techniques. Gas chromatography-mass spectrometry measurements revealed the presence of phenolic compounds in the M. pulegium extract. In addition, a strong coordination connection between Zn2+ and the chitosan matrix was confirmed, which resulted in a good dispersion of ZnO in the chitosan film. The surface of the composite films was transparent, smooth, and uniform, and the flexible bio-based hybrid films exhibited significant antibacterial and antioxidant characteristics, strong visible emission in the 480 nm region, and UV-blocking properties. The ZnO/CS films displayed a potential to extend the shelf life of fruits by up to eight days when stored at 23°C, and also acted as an acceptable barrier against oxygen and water. The biodegradable ZnO/CS film is expected to keep fruit fresher than general chemical plastic films and be used for the packaging of active ingredients.

Development of flexible scintillation sensors based on Ag and Gd doped CdWO4 nanocomposites.

In this work, CdWO4 (CWO), CWO: Ag, and CWO: Gd nanoparticles (NPs) were synthesized by a simple method. Incorporation of the prepared NPs in a polymeric matrix (Polyester) developed a highly luminescent and ionizing ray nanocomposite sensor. Results from XRD, XPS, FE-SEM and EDAX, verified the successful synthesize of pure and doped CWO nanoparticles with the mean size of approximately 50-70 nm. The luminescence properties of the synthesized NPs were examined under UV and ion-beam excitation. CWO: Ag nanoparticles exhibited the most intense emission in the blue-green range compared to the CWO and CWO: Gd samples. The scintillation response of the prepared composite films against alpha irradiation (241Am source) was studied. The highest absolute efficiency (ε) was obtained for CWO: Ag composite film (58.18%) which has promising applications in flexible and transparent optical detectors.

Facile synthesis of ZnO/CWO nanocomposite with brilliant enhanced optical response.

In this research, novel zinc oxide/cadmium tungstate (ZnO/CWO) nanocomposite was prepared by a simple chemical method. The prepared nanocomposite was characterized for its structural and optical properties by different techniques. For the first time, the radiation response of prepared nanocomposite was studied using 241Am alpha source and ion beam induced luminescence (IBIL) measurement. Also, photocurrent transient responses of the prepared nanocomposite were recorded under Xe source radiation. ZnO/CWO nanocomposite exhibited strong light emission in the blue-green range at room temperature. Under alpha irradiation, the ZnO/CWO nanocomposite showed an excellent sensitivity when compared to pure ZnO or CWO. FESEM and TEM images showed a uniform distribution of spherical nanoparticles with an average particle size of 77 nm. XRD, XPS, and EDX results indicated characteristic peaks of ZnO, CWO, and related elements in the composite. Fourier transform infrared spectroscopy confirmed the presence of several groups in the nanocomposite. Investigations indicated that the optical quality of the ZnO/CWO nanocomposite was improved when compared with pure ZnO and CWO. According to obtained results, it is anticipated that ZnO/CWO nanocomposite would hold suitable potential for applications in optoelectronic devices and detection.

Impact of nanostructured thin ZnO film in ultraviolet protection.

Nanoscale ZnO is one of the best choices for ultraviolet (UV) protection, not only because of its antimicrobial properties but also due to its potential application for UV preservation. However, the behavior of nanostructured thin ZnO films and long-term effects of UV-radiation exposure have not been studied yet. In this study, we investigated the UV-protection ability of sol gel-derived thin ZnO films after different exposure times. Scanning electron microscopy, atomic force microscopy, and UV-visible optical spectroscopy were carried out to study the structure and optical properties of the ZnO films as a function of the UV-irradiation time. The results obtained showed that the prepared thin ZnO films were somewhat transparent under the visible wavelength region and protective against UV radiation. The UV-protection factor was 50+ for the prepared samples, indicating that they were excellent UV protectors. The deposited thin ZnO films demonstrated promising antibacterial potential and significant light absorbance in the UV range. The experimental results suggest that the synthesized samples have potential for applications in the health care field.