RESUMEN
A comparative study was applied to investigate the potential of Callistemon citrinus (bottlebrush) flower extract (BBE) and Punica granatum (pomegranate) peel extracts (PPE) for the sustainable synthesis of the silver nanoparticles, Ag-BBE and Ag-PPE, respectively. The synthesis process of Ag NPs using the selected extracts was applied under optimized conditions. Hence, the effect of the selected plant's type on the different characteristics of the synthesized green Ag NPs was investigated. The UV-Vis spectroscopy revealed the presence of the characteristic silver peaks at 419 and 433 nm of the Ag-BBE and Ag-PPE, respectively. The XRD spectra reported the fcc phase formation of Ag NPs. The TEM results highlighted the morphological features of the synthesized Ag NPs. with a size range of 20-70 nm, and with 10-30 nm for Ag-BBE and Ag-PPE, correspondingly. The Raman spectra revealed characteristic silver bands in the Ag-PPE and reflected some bands related to the natural extract in the Ag-BBE sample. The antimicrobial activity and statistical analysis investigation were conducted against four selected oral pathogens (Staphylococcus aureus (SA), Candida albicans (CA), Staphylococcus epidermidis (S. epi), and Enterococcus faecalis (EF)). Both tested extracts, BBE, and PPE, revealed potential effectivity as reducing and capping agents for Ag NP green synthesis. However, the synthesized NPs demonstrated different features, depending on the used extract, reflecting the influence of the plant's biomolecules on the nanoparticles' properties.
RESUMEN
In the current report, we have successfully synthesized nanocomposites of PMMA incorporating different doping of CeO2 through a chemical approach. XRD results reflects decent matching for CeO2 nanoparticles with 29 nm crystallite size. FTIR spectroscopy demonstrates the characteristic functional groups validating the successful formation of the composite. The optical study of PMMA and the nanocomposites has proven that the optical properties such as band gap, refractive index, optical permittivity, and loss tangent factor are affected by adding CeO2 to the PMMA matrix.The peak residing around 420 nm by UV measurements is allocated to occurring electrons photoexcitation from the valence to conduction band inherent in CeO2. The dielectric measurements were achieved using broadband dielectric spectroscopy upon a wide span of frequencies (10-1-107 Hz) and within temperatures from - 10 to 80 °C with a step of 10 °C. The permittivity decreases by adding CeO2 and the dielectric parameters are thermally enhanced, however, the temperature influence is based on CeO2 content, the higher the CeO2 amount, the higher the influence of temperature. The results of the nanocomposites revealed antibacterial activity counter to gram-positive bacteria strain (S. aureus, and B. subtilis), and gram-negative bacteria (E. coli, and K. pneumoniae), yeast (C. albicans, as well as fungi (A. niger). Inherently, the change in CeO2 concentration from 0.01 to 0.1 wt% delivers maximum influence against gram-negative bacteria. These PMMA CeO2-doped composites are beneficial for optoelectronic areas and devices.
RESUMEN
Humidity sensing has been offering a noticeable contribution in different industrial, medical, and agricultural activities. Here, graphene quantum dots doped with polyaniline (PANI) and MnO2 were successfully prepared. The synthesized system is exposed to a set of structural, morphological, and optical investigations. The apparent crystallite size is less than 30 nm, reflecting the nanoscale of the structure, and thus validating the preparation route as evident on XRD pattern. SEM images show a fibrous structure where polyaniline dominates and covers most of the structure's surface. The evident bands of the FTIR spectrum are designated to the component used in synthesis confirming the chemical structure of the fabricated system. The humidity sensing study of the synthesized structure is carried out through a wide range of relative humidity (RH) levels range of 11-97%. The response and recovery times of the fabricated structure are found to be around 120 and 220s, respectively.
RESUMEN
This article investigates the effect of Ni2+ content on structural (XRD, XPS), morphological (TEM), and magnetic behaviors of silica magnesium zirconium copper nanoceramics calcined at 800 °C. The sol-gel route is followed for the silica magnesium zirconium copper/(0.0-0.7) Ni2+ samples preparation. X-ray photoelectron spectroscopy is employed to analyze the chemical states of elements for the samples. The three representative binding energy magnitudes for O, Ni, and Cu reside at 534, 857, and 979 eV, consecutively. The saturation magnetization constricts with the elevation of Ni2+ content, while the magnetic hysteresis loop resembles the superparamagnetic attitude. The optical spectra present the possibility of direct and indirect transitions in the prepared nanoceramics. Energy gap (value and type), refractive index, and real and imaginary dielectric constant were extracted. The energy gap approaches 3.75 eV and 3.71 eV for direct and indirect transitions correspondingly with (0.7) Ni2+. The antimicrobial and the toxicity performance of all inspected nanocomposites were conducted against pathogenic microbes. The attained results evidenced that SMZC-0.7Ni possesses energetic antimicrobial potential against all targeted microbes. The investigated SMZC-0.7Ni nanocomposite functioned to eradicate frequent waterborne pathogens in wastewater at an appropriate dose (100 mg/L), demonstrating that SMZC can be utilized as a competent disinfectant in the municipal wastewater decontamination process. Inherently, SMZC-0.7Ni can be employed as an excellent nano-weapon against multiple dangerous microorganisms.