ZnO and MgO nanoparticles: Synthesis and comparative study on their properties

We report the optical and structural properties of ZnO and MgO nanoparticles. The samples are obtained by a simple method using a new template of hexamethylene tetramine. The optical properties of the samples are studied by UV-visible spectroscopy. Their crystal structure and morphology are studied by XRD and scanning electron microscopy. The absorption spectra of MgO and ZnO show that the optical band gaps are 4.27 eV and 3.02 eV, respectively. In this investigation the photocatalytic degradation of indigo carmine (IC) in water is studied. The effects of some parameters such as pH, amount of catalyst, initial concentration of dye, are examined.     

Preparation of a dual-functionalized fumed silica nanoparticle catalysis for synthesis of azaluorenone derivatives

Research on Chemical Intermediates - A dual-functional silica-based catalyst was prepared by treating fumed silica with amino-containing silane then 1,4-butane sultone. The presence of functional...     

Simultaneous removal of Cu2+ and Cr3+ ions from aqueous solution based on Complexation with Eriochrome cyanine‐R and derivative spectrophotometric method

TiO₂ nanoparticles deposited on activated carbon (TiO₂–NP–AC) was prepared and characterized by XRD and SEM analysis. Subsequently, simultaneous ultrasound‐assisted adsorption of Cu²⁺ and Cr³⁺ ions onto TiO₂‐NPs‐AC after complexation via eriochrome cyanine R (ECR) has been investigated with UV–Vis and FAA spectrophotometer. Spectra overlapping of the ECR‐Cu and ECR‐Cr complex was resolve by derivative spectrophotometric technique. The effects of various parameters such as initial Cu²⁺ (A) and Cr³⁺ (B) ions concentrations, TiO₂‐NPs‐AC mass (C), sonication time (D) and pH (E) on the removal percentage were investigated and optimized by central composite design (CCD). The optimize conditions were set as: 4.21 min, 0.019 mg, 20.02 and 13.22 mg L^?1 and 6.63 for sonication time, TiO₂–NP–AC mass, initial Cr³⁺ and Cu²⁺ ions concentration and pH, respectively. The experimental equilibrium data fitting to Langmuir, Freundlich, Temkin and Dubinin–Radushkevich models show that the Langmuir model is a good and suitable model for evaluation and the actual behavior of adsorption process and maximum adsorption capacity of 105.26 and 93.46 mg g^?1 were obtained for Cu²⁺ and Cr³⁺ ions, respectively. Kinetic evaluation of experimental data showed that the adsorption processes followed well pseudo second order and intraparticle diffusion models.     

Sensitivity optimization of PRESAGE polyurethane based dosimeter

A new class of three-dimensional dosimeter (PRESAGE) has recently emerged, that consists of an optically clear polyurethane matrix containing a leuco dye and a free radical initiator. The dye exhibits a radiochromic response when exposed to ionizing radiation, changing color in proportion to the radiation dose. In this work we investigate and characterize the sensitivity of this new dosimeter by changing the portion of these two materials in the feature. Our results show considerable improvement in both dosimeter sensitivity and dose response stability by changing the percents of leuco dye and free radical initiator to approach to an optimum value.     

Electronic, Energetic, and Geometric Properties of Methylene-Functionalized C60

Chemical functionalization of C₆₀ fullerene with one to six carbene (CH₂) molecule(s) has been investigated using density functional theory. We have found that the reaction is regioselective so that a CH₂ molecule prefers to be adsorbed atop a C–C bond which is shared between two hexagonal rings of the C₆₀, releasing energy of ?3.95 eV. Singly occupied molecular orbital (SOMO) of the CH₂ interacts with LUMO of the C₆₀ via a [2 + 1] cycloaddition reaction. Energy of the reaction and work function of the system are decreased by increasing the number of adsorbed CH₂ molecules. The HOMO/LUMO energy gap of C₆₀ is slightly changed and the electron emission from its surface is facilitated upon the functionalization.     

Effect of axial strain on structural and electronic properties of zig-zag type of boron nitride nanotube (BNNT): a quantum chemical study

The influence of strain on structural and electronic properties of zig-zag type of boron nitride nanotubes (BNNTs) has been studied by density functional theory calculations. The variations of HOMO–LUMO gaps, geometrical parameters, cohesive energy, radial buckling, isodensity surfaces of the HOMOs and LUMOs, electrophilicity index, chemical potential, and chemical hardness and softness have been investigated for BNNTs at different strains. Our results show that the effect of axial strain on the electronic and structural properties of zig-zag BNNTs depends on the diameter as well as the length of the nanotube.     

Preparation and characterization of cellulose-ZnO nanocomposite based on ionic liquid ([C4mim]Cl)

Cellulose-ZnO composite was achieved by microwave assisted dissolution of cellulose in ionic liquid 1-butyl-3-methylimidazolium chloride ([C₄mim]Cl) followed by addition of premixed ground of Zn(CH₃COO)₂·2H₂O and NaOH. Surface characterization, optical property and thermal stability of nanocomposite were determined by X-ray diffraction, scanning electron microscopy (SEM), UV–Vis spectroscopy and thermo gravimetric analysis. XRD patterns showed the ZnO in polymer matrix has the wurtzite structure. Presence of zinc oxide nanoparticles and cellulose fibers in the composites were observed by SEM. Band-edge transition of zinc oxide in the nanocomposite occurs in lower wavelength than bulk zinc oxide. Thermal stability of nanocomposite was lower than regenerated cellulose due to catalyst behavior of zinc oxide nanoparticles in cellulose matrix.     

Stability and Rheological Properties of Suspended Pulp Particles Containing Orange Juice Stabilized by Gellan Gum

Gellan was used to suspend pulp particles in orange juice. Three groups of samples were prepared with 0%, 20%, and 40% orange juice concentrate and supplemented with gellan at different concentrations. A concentration-dependent increase in the size of gellan aggregates and gellan-protein assemblies was observed. Incorporation of gellan into the beverage with 0% juice concentrate changed the rheological behavior of sample to non-Newtonian shear-thinning fluid and increased its surface tension. When juice concentrate proportion was increased from 0% to 20%, the beverage viscosity increased. The highest gellan concentration resulted in a higher yield stress (σ₀) value and inhibited the pulp sedimentation completely.