فهرست مطالب

  • Volume:7 Issue:1, 2018
  • تاریخ انتشار: 1397/07/07
  • تعداد عناوین: 8
|
  • Alkyl surface modification of nanoporous silica SBA-15 by click chemistry to obtain triazole products
    N. Lashgari, A. Badiei, P. Hajiabbas Tabar Amiri, G. Mohammadi Ziarani* Pages 5-12

    In this study, Santa Barbara Amorphous (SBA-15) mesoporous silica has been functionalized with aminopropyl groups that were converted to propargyl-bearing moieties through the reaction with propargyl bromide. The material then underwent an efficient Cu(I)-catalyzed azide alkyne click reaction with sodium azide in order to obtain the corresponding triazole products. The covalent modification of mesoporous silica surface with organic functional groups was confirmed by different characterization techniques including Fourier transform infrared spectroscopy, thermogravimetric analysis, Scanning electron microscopy, Transmission electron microscopy, N2 adsorption-desorption isotherms and Raman spectroscopy. The results have confirmed that SBA-15 was successfully functionalized with organic moieties. No change in the periodic structure of the SBA-15 silica support was observed throughout the grafting procedure. Surface area, pore size and pore volume decreased by attaching functional groups to the pore surface. This approach provides a simple and convenient route to efficiently functionalize a wide range of new structures on the surface of SBA-15

    Keywords: Click reaction, Functionalized SBA-15, Huisgen 1, 3-dipolar cycloaddition, Mesoporous silica, Propargyl bromide
  • Selective oxidation of sulfides to sulfoxides by a vanadium-based catalyst using 30% hydrogen peroxide
    M. Didwar, M.J. Taghizadeh* Pages 13-19

    The vanadium-based catalyst, acts as a homogeneous catalyst for the selective oxidation of various kinds of sulfides with 30% aqueous H2O2. Vanadium-based catalyst was successfully used as the oxygen source for the oxidation of sulfides to sulfoxides for the first time. The sulfoxides were obtained in a good way to high yields without any detectable over-oxidation to sulfones under normal conditions. Different functional groups including C– C double bond, ester, ketone, acetal, alcohol, and oxime groups are tolerated under this reaction condition. The prepared catalyst was used to achieve a high-efficiency, low cost, ecofriendly and easy to handle protocol for synthesizing substituted sulfoxide derivatives from sulfides. The catalyst could be recycled for up to four runs without significant loss in catalytic activity. A green, efficient and selective approach for the oxidation of sulfides to sulfoxides and with stoichiometric amount of 30% aq. H2O2 is reported.

    Keywords: Heterogeneous, Hydrogen peroxide, Sulfoxidation, Selective oxidation, Vanadium
  • The immobilization of laccase enzyme from Trametes versicolor on the surface of porous zinc oxide nanoparticles and studying features of the immobilized enzyme
    M. Ebrahimi*, N. Farhadyar, Gh. Ghorbani Pages 21-28

    The laccase enzyme is the largest group of Oxidoreductase enzymes and is capable of oxidizing a wide range of organic substrates to water along with molecular oxygen resuscitation. ZnO nanoparticles are known for their specific properties such as chemical stability, high electrochemical coupling rates, and wide range of absorption of radiation as multifunctional compounds. In this study, ZnO porous nanoparticles were synthesized and then the laccase enzyme was stabilized from the source of vermicellum tramitis by surface absorption method on the surface of synthesized nanoparticles. In the following, kinetic parameters, temperature stability, reusability and sustainability of the stabilized enzyme were measured and compared with the free enzyme. Given the results obtained at all three temperatures (40, 50 and 60 °C), the stabilized enzyme shows more temperature stability than the free enzyme in desired time range. The kinetic parameters Vm and Km did not significantly change with respect to the free enzyme. Enzyme activity returned to zero after 10 cycles of use and recycling. While the free enzyme lost its activity after three weeks of maintenance in laboratory condition, the stabilized enzyme retained 30% of its initial activity. These results indicate that ZnO porous nanoparticles can be used as a suitable substrate for the stabilization of laccase enzyme by surface adsorption method, and improves the stability parameters of the enzyme without affecting the kinetic properties of the enzyme

    Keywords: Immobilization, Laccase, Porous ZnO nanoparticles, Stability, Reusability, Tramitis versicolor
  • Preparation of the novel zeolite AgX/CdO NPs composite catalyst and its application for the effective removal of fenitrothion (FN) from water
    M. Sadeghi*, S. Yekta Pages 29-42

    The novel zeolite AgX/CdO NPs composite catalyst has been fabricated under an ultrasound assisted dispersion route and identified by various analysis including FTIR, XRD, FESEM-EDAX, AFM, TEM, and EDAX-Dot mapping. Afterwards, for the first time, the zeolite AgX/CdO NPs composite has been exerted for the effective removal (adsorption and degradation) of fenitrothion (FN, O,O-dimethyl-O-(3-methyl-4-nitrophenyl phosphorothioate) as an organophosphorus pesticide from water, and the 31PNMR and GC-MS analysis proved its substantial applicability against fenitrothion. The impacts of diverse parameters on the removal outcome of fenitrothion were investigated. The 31PNMR data verified that fenitrothion was removed by the zeolite AgX/CdO NPs composite. To study the reaction kinetic, the first order model was studied. The quantities of the half-life (t1/2) and rate constant (k) calculated as 13.91 min and 0.0498 min-1, respectively. The less toxic products of dimethyl phosphorothioic acid (DMPA) and 3-methyl-4-nitrophenol (3-M-4-N) from the degradation and hydrolysis reaction were identified

    Keywords: AgX, CdO NPs, Composite, Catalyst, Degradation, Fenitrothion, Removal
  • Solid phase extraction of trace cobalt (II) in industrial wastewaters by modified nanotube carbon carboxyl and its determination with flame atomic spectroscopy
    H. R. Shahbazi, A. Moghimi*, H. Heidari Pages 43-57

    Applying a simple and selective sample preparation procedure prior to instrumental analysis is the most important and crucial step in an analytical process. Up to now, various sample preparation techniques based on solid phase extraction (SPE) systems have been developed to isolate various types of analytes from different matrices. In the method presented for preconcentration and measurement of trace amounts of cobalt (II) ions in aqueous samples, carbon nanotubes functionalized with carboxyl were used for improving the extraction and preconcentration action. Measurement of Co2+ ion concentration in aqueous solutions was performed by flame atomic absorption spectroscopy. The parameters including the extraction including pH, amount and type of desorption solvent, extraction time, the effect of other ions, etc. were optimized. The concentration factor, level of detection (LOD) of the method, and relative standard deviation (RSD %) were obtained as 20.83, 6 μg.L-1, and 1.16%, respectively

    Keywords: Carbon nanotubes functionalized with carboxyl, Co (II) ion, FAAS, Flame atomic absorption spectroscopy, Preconcentration, SPE
  • Measurement and comparison of trans fatty acids amount in some of the vegetable oils, frying oils and animal and vegetable fats in Iran
    S. Asadollahi*, E. Hosseini, N. Vasei Chaharmahali Pages 59-64

    The role of dietary fats and oils in human nutrition is one of the most important areas of concern and investigation in the field of nutritional science. The findings of investigations on this subject have wide-ranging implications for consumers, health-care providers and nutrition educators as well as food producers, processors and distributors. New evidence concerning the benefits and risks associated with particular aspects of dietary fat. Physically, oils are liquid at room temperature, and fats are solid. Chemically, both fats and oils are composed of triglycerides. In this study, different fatty acids especially trans fatty acids in 9 samples of oil including liquid and frying oils and processed and non-processed solid fats in the Iranian market were investigated. The experiments were performed by gas chromatography. Trans fatty acids were detected from 33% to 52.8%. The highest content of trans fatty acid was identified in animal oil

    Keywords: Dietary Fat, Gas chromatography, Oil, Trans fatty acids, Triglycerides
  • Bredigite (BG) as a novel nanobioceramic powder; investigation and characterization
    E. Karamian, H. Gheisari Dehsheikh* Pages 65-69

    In this project, Bredigite (BG) has been successfully prepared by a modified sol-gel method. Optimization in calcination temperature and mechanical ball milling resulted in a pure and nano-sized powder which characterized by means of X-ray diffraction; scanning electron microscopy, transmission electron microscopy and Fourier transform infrared Spectroscopy. We hypothesized that nano-sized Bredigite (BG) would mimic more efficiently the nanocrystal structure and function of natural bone apatite, owing to the higher surface area, compare to conventional micron-size Bredigite (BG). Accordingly, we used the unique advantage of nanotechnology to improve novel nanobredigite (NBG) particles as a potential candidate for bone tissue regeneration whether as a peri-implant filling powder or in combination with other biomaterials as a composite scaffold

    Keywords: Bredigite (BG), Nano bioceramic powder, SEM, TEM, X-ray diffraction
  • Green synthesis of Iron oxide nanoparticles using carum carvi L. and modified with chitosan in order to optimize the anti-cancer drug adsorption
    E. Moniri, Seyed A. Alavi, A. Izadi, R. Safaeijavan* Pages 71-78

    Magnetic iron oxide nanoparticles have gained a lot of attention in drug delivery systems because they can control a drug pathway to deliver it to the specific site under a magnetic field which is related to their magnetic core and surface coating. Chitosan-coated FeNPs, have prominent antimicrobial and biological properties that make chitosan a promising biopolymer for drug delivery application, especially in cancer treatment. In this research, FeNPs were green synthesized using the aqueous extract of Carum carvi L. and under optimum conditions. Formation of FeNPs was confirmed by UV-Vis spectroscopy, XRD analysis, and SEM. Also, chitosan-coated FeNPs were synthesized to increased biocompatibility and the absorption capacity of nanoparticles. Chitosan coating on FeNPs was detected by FTIR. After the production of nano-absorbent, the maximum absorbance of different concentrations of doxorubicin was determined. The effect of pH was investigated on the absorption of doxorubicin in maximum absorbance at pH 3-10 by UV-Vis spectroscopy. The results obtained from the characterization of FeNPs showed they are spherical particles with less than 300 nm in size. The maximum absorbance of different concentrations of doxorubicin was in 280 nm. Doxorubicin showed maximum absorption at pH 7. This green biosynthesis method has been found to be eco-friendly, cost-effective and promising for different applications. The seeds extract of Carum carvi L. have a great ability to reduce Fe ions to FeNPs. Also, doxorubicin loaded chitosan-coated FeNPs can successfully use in drug delivery systems

    Keywords: Doxorubicin, Drug delivery, Green synthesis, Iron nanoparticles, surface modification