فهرست مطالب

Particle Science and Technology - Volume:8 Issue: 1, Spring 2022

Journal of Particle Science and Technology
Volume:8 Issue: 1, Spring 2022

  • تاریخ انتشار: 1401/09/28
  • تعداد عناوین: 6
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  • Mohammadmehdi Namazi *, Amir Fassih, Amir Mobini Pages 1-7
    Flameless catalytic heaters are thermal systems in which the chemical energy of gaseous fuel converts into heat with zero NOx and low CO (≤ 10 ppm) emissions. Hence, they are called green heaters in the industry. These heaters benefit from a fibrous porous medium as support for catalyst nanoparticles. Pore structure has a significant effect on transport phenomena inside the porous medium. With the dramatic growth of computers, it is possible to study the impact of geometric detail on combustion phenomena. This study investigates the effect of fiber orientation and diameter on the temperature distribution and the reaction zone of CH4 catalytic combustion in the fibrous medium. As the fiber axis angle increases from 10° to 90°, the reaction zone moves 24.1% toward the reactor inlet, the maximum temperature increases by 69.7 °C, and its distribution becomes more non-uniform. Moreover, as the diameter of the fibers increased from 5 µm to 10 µm, the reaction site moved 29.8% toward the end of the reactor, the maximum temperature increased by 34.9 °C, and its distribution became slightly more uneven. The results showed how the diameter and orientation of fibers influence the performance of porous catalytic reactors. This issue should be considered, especially to increase the life of catalytic burners.
    Keywords: Catalytic Combustion, Fibrous Porous Medium, Fibers Orientation, Fibers Diameter
  • Saeid Jabbarzare * Pages 9-16
    A simple method was applied to construct Ni-doped CaTiO3 nano-powders from commercial CaCO3 and TiO2, characterized by XRD, FE-SEM, and FT-IR. The sample was composed of small grains with an average size of 78 nm. This method could be a useful, inexpensive, and efficient tool for the preparation of Ni-doped CaTiO3 nano-powders. The prepared sample was used for the removal of Cd2+ from water media. Results indicated that Cd2+ removal by Ni-doped CaTiO3 nano-powders was very efficient (100% removal yield) when the pH was adjusted to 4.5, the catalyst dosage amounted to 0.05 g, and the Cd2+ solution concentration was 60 mg.L-1. A pseudo-second-order kinetic model described the kinetics of Cd2+ removal.
    Keywords: CaTiO3 Nano-powders, Ni-Doped CaTiO3, Cd2+ Removal, Wastewater, adsorption experiment
  • Fatemeh Mobayyen Jarihani, Farajollah Mohannazadeh * Pages 17-23
    Considering that preparing microparticle drugs enhances their solubility and bioactivity, it is the pharmaceutics’ interest to have more information about the drug’s particle size; hence, it is essential to study a drug’s particle size and morphology. So far, no work has been done on the particle size of acamprosate calcium. In this work, micronized acamprosate calcium was first prepared, then its water solubility was investigated. To this aim, acamprosate calcium was synthesized from 1,3-propane sultone through two-step reactions. The resulting powder was then micronized using Triton-X-100 using the in situ micronization method. The resulting micronized particles were found to be highly pure (99.7 %). The micronized acamprosate calcium's particle size was less than 10 µm. Kinetic solubility studies showed that micronized acamprosate calcium's water solubility had improved compared to bulk particles of acamprosate calcium.
    Keywords: Acamprosate calcium, Micronized drugs, Solubility, In situ micronization, Triton-X-100
  • Roya Mashayekhi, Morteza Ehsani *, Shervin Ahmadi, Ramin Khajavi, Hossein Ali Khonakdar Pages 25-37
    The PA6/clay nanocomposites were prepared during in-situ anionic ring-opening polymerization (AROP) via reactive melt blending in a Hakke internal mixer. Then, the samples were characterized using FT-IR, DSC, DMTA, rheometer, XRD, SEM/EDX/elemental mapping, TEM, and HT-GPC to study the effects of Cloisite 15A on PA6 properties. The results showed that nanoclay caused a decrease in the ultimate tensile strength (UTS), crystallinity, Tm, Tg, and tan δ of the samples. However, it increased the Young′s modulus and stress rupture of the samples. Furthermore, the nanocomposites showed a pseudo-solid behavior because of the reinforcing effect of the nanoparticles. Additionally, α crystals were not seen in the samples with 1 and 3 % nanoclay; however, γ crystals were observable in those samples. Also, nanoclay decreased PA6 viscosity and increased dispersity and residual monomers in the nanocomposite samples. The nanoclays exfoliated in the sample have 0.5 % nanoparticles, but they were intercalated by more loading in the PA6 matrix. Moreover, the PA6 microfibrils were observed as sporadic and clay-centered clusters in the SEM micrographs of the pure and nanocomposite samples, respectively. Therefore, the clustering of PA6 microfibrils in the matrix during in-situ AROP is considered a novelty in current research.
    Keywords: Polyamide 6, Nanoclay, nanocomposites, Clusters, In-Situ Polymerization
  • Marzieh Bayat, Maryam Ranjbar *, Soheila Shokrollahzadeh Pages 39-51
    Ozone has received much attention in wastewater treatment as an impressive oxidation agent. In this work, three new metal complexes, [pyda.H][Fe(pydc)(pydc.H)].H2O, (I); [pyda.H][Fe(pydc)2].H2O, (II); and [pyda.H2]5[Mn(pydc.H)2].[pydc]5.8H2O, (III), where [pyda.H]+ = 2,6 -diaminopyridinium and [pydc]2- = 2,6 -pyridinedicarboxylate, have been synthesized by the ultrasonic-assisted synthesis method and then characterized by field emission scanning electron microscope (FE-SEM), Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric (TGA), and elemental analyses. According to the SEM image, the morphology of compound III was a nanorod. Compounds I, II, and III were then used as precursors for the preparation of Fe3O4, Mn3O4, and Mn3O4/Fe3O4 using the sol-gel and impregnation methods, respectively. Characterization of the synthesized nano-catalysts was carried out by FE-SEM, X-ray powder diffraction (XRD), and energy diffraction X-ray (EDX), the vibrating sample magnetometer (VSM) was replaced by magnetic studies. The VSM result showed that Fe3O4 and Mn3O4/Fe3O4 were superparamagnetic and ferromagnetic compounds, respectively. The Mn3O4, Mn3O4/Fe3O4, and Fe3O4 nanocatalysts were applied for the decomposition of phenol in an aqueous solution by catalytic ozonation. Phenol degradation efficiency was obtained as 97.26, 97.74, and 88.62 %, respectively.
    Keywords: Mn3O4, Fe3O4 nanocomposite, sol-gel method, Synthesis, catalytic ozonation, phenol degradation
  • Synthesis and characterization of the aminated nano-zeolite: A green heterogeneous nanocatalyst for the synthesis of valuable organic compounds
    Khadijeh Rabiei, Fatemeh Najafi Pages 53-62

    In this study, natural surface-modified nano-clinoptilolite, NCP@SiO3Pr(CH2)6N4, was synthesized and fully characterized using various analytical techniques, including FT-IR, XRD, SEM, EDS, TEM, and TG-DTA analyses. Additionally, this aminated nanocatalyst was evaluated for the effective synthesis of α,β-unsaturated carbonyl compounds containing valuable substances such as barbituric acid moiety under solvent-free conditions. This catalyst obtained desired products with excellent yields, high purity, and short reaction times. Furthermore, the synthetic, non-toxic heterogeneous nanocatalyst is easily recycled and can be reused several times.

    Keywords: NCP@SiO3Pr(CH2)6N4, α, β-Unsaturated compounds, Clinoptilolite, Green nanocatalyst, Barbituric acid