Journal of Nanoanalysis
Volume:8 Issue: 3, Sep 2021

In this research, a synthesized nano photocatalyst was prepared by supportingZnO nanoparticle on Lightweight expanded clay aggregate (LECA). The catalystwas synthesized by the co-precipitation method. The SEM, FT-IR, and XRD testswere used to characterize ZnO/LECA, which was employed for photocatalyticremoval of Cr (VI) from an aqueous solution in a batch photoreactor. The fullfactorial experimental design (FFD) was used for the statistical analysis of data.The influence of catalyst amounts, pH, and initial concentration of Cr (VI) wasinvestigated on the reduction of Cr (VI) to Cr (III). The number of active sites wasincreased with an increase in the concentration of catalyst to some extent. Also,the selection of other factors in the optimized amount was important. The optimalconditions were obtained at 0.75 g/l of photocatalyst, pH at 5 and 20 mg/l ofCr(VI). The experimental and predicted reduction efficiency by FFD at optimalconditions were 97.6 and 96.18%, respectively. The comparison of experimentaland predicted data showed a good agreement between them.

Nanoparticles have a wide range of applications due to their unique biological andphysicochemical properties. Among metal nanoparticles, silver nanoparticlesare of special importance due to their wide application. Although there are severalchemical and physical methods for the synthesis of silver nanoparticles, biologicalmethods are more suitable due to their time and low energy, non-use of toxicsolvents, and biocompatibility. In this study, an aqueous extract of dried flowers ofAchillea eriophora (Shirazi yarrow) was used as a reducing agent for the synthesisof silver nanoparticles. The reaction was performed at room temperatureand showed a change in color from pale yellow to dark brown to form silvernanoparticles. UV-Vis spectroscopy, scanning electron microscopy (SEM), Fouriertransforms infrared spectroscopy (FTIR) and particle sizing (PSA) were used toevaluate the physicochemical properties of the formed nanoparticles. Thepresence of an absorption peak at a wavelength of about 450 nm confirmed theformation of silver nanoparticles. SEM results showed that the shape of particleswas spherical and their particle size ranges were from 38 to 144 nm. FTIR resultsalso showed the role of reducing groups on the surface of nanoparticles. Theresults of PSA showed that the particles have low polydispersity and the extractis desirable for the synthesis of silver nanoparticles. Based on these results, itcan be said that the synthesis of silver nanoparticles by Shirazi yarrow extractis a simple, fast, non-toxic, and biocompatible method and can be used in food,medicine, and agriculture.

In this project, the TiO2 nanorods were synthesized from P25 TiO2 nanoparticlesby the hydrothermal method in 20 M NaOH solution. The effects of annealingtemperatures on produced nanorods were investigated by scanning electronmicroscopy (SEM) X-ray diffraction (XRD) and photoluminescence (PL)spectroscopy. An increase of annealing temperature over 300 °C has no effect on thesize of produced nanorods, but due to reduction of the surface charge causes themore compact products. In addition, the surface defects of synthesized 1D TiO2were decreased because of an increase in annealing temperatures, but we shouldnote that at higher temperatures (over 500 °C) the TiO2 phase may be convertedfrom anatase to rutile.Diameter growth and changes of surface oxygen defects ofsynthesized Nanorods are studied with increasing annealing temperatures. Also,with an increase in annealing temperature over 300 °C, there is no effect on the sizeof produced nano-rods, but due to reduction of the surface charge causes themore compact products.

Due to the natural bone microstructure, the design and fabrication ofporous ceramic scaffold nanocomposite materials coated with a thin layer of a naturalthe polymer can provide an ideal scaffold for bone tissue engineering. This study aimed tofabricate multi-component porous magnetic scaffolds by freeze-drying (FD) techniqueusing a gelatin polymer layer coated with a gentamicin drug.

Magnetic nanoparticles (MNPs) can be manipulated and controlled byan external magnetic field gradient (EMFG) that is inherent in the magnetic field'spermeability within human tissues. In the present work, unlike the usual ceramic/polymer composite scaffold, the ceramic components, and the magnet were placedtogether in the reaction medium from the beginning, and bioceramics were replacedin the composite polymer network and then coated with a drug-loaded polymer. Toevaluate the morphology of the magnetic scaffold, scanning electron microscopy(SEM) was utilized to evaluate the microstructure and observe the porosity of theporous tissue.

After analyzing the SEM images, the porosity of the scaffolds was measured,which was similar to the normal bone architecture. The addition of gentamicin tothe gelation was investigated to monitor the drug delivery reaction in the biologicalenvironment. The magnetic properties of the sample were evaluated using thehyperthermia test for 15 seconds at the adiabatic conditions. Also, the porosity valueincreased from 55% to 78% with the addition of MNPs to the based matrix.

The results of this study showed that gentamicin-gelatin-coated onporous ceramic-magnet composite scaffolds could be used in bone tissue engineeringand apply for treatment of bone tumors, because of their similarity to the bonestructure with good porosity.

The catalytic reaction of iridium nanoparticles was carried out over gamma aluminagranules to investigate the factors controlling the catalytic activities.The evaluation of iridium nanoparticle activity in the laboratory reactor wasdone for support grains with different diameters between 1 mm to 4 mm. Thecharacterization of three iridium catalysts was evaluated by XRD, FESEM andEDX before and after catalytic activity. The rate of hydrazine decomposition andhydrogen selectivity increased to 306 h-1 and 42% with the better distributionof nanoparticles, regardless of the grain size of catalyst support, whereas thehydrazine decomposition rate was larger for smaller supported catalysts. Theprobability of hydrazine monohydrate molecules in contact with active sitesbecomes higher and the movement of reactants and gas products will be easyinside and outside the pores, leading to the increase in reactivity. The rate of thehydrazine monohydrate decomposition and H2 selectivity decreased to 216 h-1and 26% with the lower catalyst grains and the higher size of support along withworse distribution on the surface. The remarkable results of results prove thatsupport granule size is a dominant factor in catalytic decomposition.

In this paper, the precipitation method has been used to stabilize Fe2O3 particleson Bentonite zeolite (BEN). Fe2O3/BEN catalysts have been characterized byscanning electron microscopy (SEM), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) surface area analysis. Artificial neural network (ANN)was used for modeling the photocatalytic degradation of Sunset Yellow FCF(SYF) azo dye in aqueous solution under irradiation in the batch photoreactor.The parameters including pH, catalyst amount, dye concentration and H2O2concentration was applied as input; the output of the network was degradationpercentage. Modeling the results of the photocatalytic degradation of dye using afeed-forward, backpropagation three-layer network, topology (4:7:1) with fourneurons in the input layer, seven neurons in the hidden layer, and one neuron inthe output layer was used. Comparison between data obtained from ANN andexperimental data indicated that the proposed ANN model provides reasonablepredictive performance. The optimum conditions were as follows: pH= 4, catalystamount=60 mg/L, dye concentration =50 ppm and H2O2 concentration =32ppm. The chemical oxygen demand (COD) analysis of the dye under optimumconditions showed a 91% reduction in 80 min period.

Doping some lanthanide ions into Sr2As2O7 crystal system is reported for thefirst time by a simple solvothermal method using Sr(NO3)2, As2O3, Er2O3 andNd2O3 compounds. Characterization of the as-synthesized nanomaterials isdone by powder X-ray (PXRD) analysis. Rietveld's analysis data confirmed thatthe synthesized materials were crystallized in a mixture of three crystal phases.FESEM images revealed that dopant ion type had a considerable effect on themorphology of the final product. The data showed that the morphology of thesynthesized materials was comb-like structure and particle. Direct bandgapenergy (Eg) of the materials obtained using ultraviolet-visible spectra showed thatthe Eg was about 3.5 eV. The synthesized nanomaterials were used as catalysts inthe Biginelli reactions. The data confirmed that the materials could behave asLewis acid catalyst in the reactions. The catalytic performance of the synthesizedsample was 92% when the catalyst amount was 0.03 g, the reaction temperature was90 °C and the reaction time was 100 min.