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Preparation,characterization and heterogeneous catalytic applications of GO/Fe3O4/HPW nanocomposite in chemoselective and green oxidation of alcohols with aqueous H2O2
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Graphene oxide ‐ Fe3O4 ‐ NH3+H2PW12O40 ‐ magnetic nanocomposite (GO/Fe3O4/HPW) was prepared by linking amino ‐ functionalized Fe3O4 nanoparticles (Fe3O4 ‐ NH2) on the graphene oxide (GO), and then grafting 12 ‐ tungstophosphoric acid (H3PW12O40) on the graphene oxide ‐ magnetite hybrid (GO ‐ Fe3O4 ‐ NH2). The obtained GO/Fe3O4/HPW nanocomposite was well characterized with different techniques such as FT ‐ IR, TEM, SEM, XRD, EDX, TGA ‐ DTA, AGFM, ICP and BET measurements. The used techniques showed that the graphene oxide layers were well prepared and the various stages of preparation of the GO/Fe3O4/HPW nanocomposites successfully completed. This new nanocomposite displayed excellent performance as a heterogeneous catalyst in the oxidation of alcohols with H2O2. The as ‐ prepared GO/Fe3O4/HPW catalyst was more stable and recyclable at least five times without significantly reducing its catalytic activity. 相似文献
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The contribution of electrospun nanofibrous membranes (e.NFMs) in the biosensing platforms opens up a new prospect for the invention of faster and more sensitive analytical devices. In this paper, we utilized e.NFM of polyethersulfone (PES) as a solid substrate for the protein immobilization through two different approaches: physical and covalent. Scanning electron microscopy (SEM) and Fourier‐transform‐infrared (FTIR) tests were performed to study the effect of plasma treatment on protein immobilization efficacy. Moreover, taking advantage of ELISA technique, the influence of different parameters, namely, nanofibers diameter, membrane thickness, plasma treatment time, an incubation time of ethyl‐3‐(3‐dimethylaminopropyl)‐carbodiimide/N‐hydroxysuccinimide (EDC/NHS), and their ratio on antibody immobilization efficacy through two mentioned approaches, was also assessed. 相似文献
3.
Valiollah Babaeipour Seyed Abbas Shojaosadati Rasoul Khalilzadeh Nader Maghsoudi Amir Mohammad Farnoud 《Applied biochemistry and biotechnology》2010,160(8):2366-2376
Development of inexpensive and simple culture media and appropriate induction conditions are always favorable for industry.
In this research, chemical composition and stoichiometric data for γ-interferon production and recombinant Escherichia coli growth were used in order to achieve a simple medium and favorable induction conditions. To achieve this goal, the effects
of medium composition and induction conditions on the production of γ-interferon were investigated in batch culture of E. coli BL21 (DE3) [pET3a-ifnγ]. These conditions were considered as suitable conditions for the production of γ-interferon: 2.5× M9 medium, supplemented
with a mixture of amino acids (milligram per liter), including glutamic acid 215, aspartic acid 250, lysine 160, and phenylalanine
90, and induction at late-log phase (OD600 = 4.5). Under these conditions, dry cell weight of 6 ± 0.2 g/l and γ-interferon concentration of 2.15 ± 0.1 g/l were obtained.
Later, without changing the concentration ratio of amino acids and glucose, the effect of increase in the primary glucose
concentration on productivity of γ-interferon was investigated. It was found that 25 g/l glucose will result in maximum attainable
biomass and recombinant human γ-interferon. At improved conditions, a dry cell weight of 14 ± 0.2 g/l, concentration and overall
productivity of γ-interferon 4.2 ± 0.1 g/l and 420 ± 10 mg/l h, respectively, were obtained. 相似文献
4.
Copper–birhodanine complex immobilized on Fe3O4 nanoparticles: DFT studies and heterogeneous catalytic applications in the synthesis of propargylamines in aqueous medium
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Heterogeneous magnetic nanocatalyst, Fe3O4@SiO2–Ligand–Cu (II) MNPs, reveals high catalytic performance within the synthesis of propargylamines using the multicomponent coupling reaction of aldehydes, phenylacetylene and secondary amines in water as a solvent. The substantial feature of this organic–inorganic hybrid magnetic nanocatalyst is the capability of straightforward separation of the reaction mixture by an external magnet which was retrieved ten times without significant loss of catalytic activity. This methodology has other advantages such as subordination to the principles of green chemistry and avoiding the use of expensive and harmful organic solvents. To study the stability and actual structure of birhodanine derivative–copper (II) complex, DFT calculations were also performed. 相似文献
5.
Acrylic coatings exhibiting improved hardness, solvent resistance and glossiness by using silica nano-composites 总被引:1,自引:0,他引:1
Ahmad Dashtizadeh Majid AbdoussHossein Mahdavi Manuchehr Khorassani 《Applied Surface Science》2011,257(6):2118-2125
To prepare nano-composite emulsion acrylic resins with improved surface hardness and solvent resistance, nano-silica particles were treated with surfactants. The monomers of methyl methacrylate/butylacrylate were co-polymerized on the surface of dispersed silica particles. Several emulsions with different silica contents and copolymer mole fractions were prepared. Finally the emulsions were modified to water-based acrylic coatings and improved properties such as surface hardness, solvent resistance and glossiness were determined. The study of coatings was directed to find the improved resin by optimum surface properties. Size distribution and morphology of latexes were characterized by Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy and scanning electron microscopy. The glass transition temperature of nano-composites was measured and discussed its relation with silica contents, monomer mole fractions and improved properties of coatings. The optimum pendulum hardness of coatings was on 0.46 methyl methacrylate mole fraction and 120 g silica content. An increase in pendulum hardness of nano-composites with the addition of modified silica was observed. DLS and TEM studies indicate that silica particles were dispersed homogenously through the polymer matrix. 相似文献
6.
Sahar Javaheri Manuchehr Babaeipour Arash Boochani Sirvan Naderi 《Chinese Journal of Physics (Taipei)》2018,56(6):2698-2709
Electronic and optical properties of pure and V-doped AlN nanosheet have been investigated using density functional theory, and the dielectric tensor is calculated using the random phase approximation (RPA). The results of structural calculations show that the V atoms tend to replace instead of aluminum atoms with the lowest formation energy. In addition, study of the electronic properties shows that pure AlN nanosheet is a p-type semiconductor that by increasing one V atom, it possesses the metallic properties and magnetic moment becomes Zero. Moreover, by replacing two V atoms, the half-metallic behavior with 100% spin polarization can be found, and each supercell gains a net magnetic moment of 3.99 µB. Optical properties like the dielectric function, the energy loss function, the absorption coefficients, the refractive index are calculated for both parallel and perpendicular electric field polarizations, and the results show that the optical spectra are anisotropic. 相似文献
7.
Gholam Reza Pazuki Vahid Taghikhani Manuchehr Vossoughi 《Journal of solution chemistry》2008,37(5):665-675
In this research, a new local composition model has been proposed to study the vapor-liquid and liquid-liquid phase equilibria
of polyelectrolyte solutions. The proposed model has been used in order to obtain the activity of water in polyethylene glycol
(PEG) and polypropylene glycol (PPG) solutions. The interaction parameters introduced into the proposed model have been reported.
The interaction parameters between the salt and water molecule have been estimated using the experimental mean ionic activity
coefficients of aqueous electrolytes studied in this work. Also, the interaction parameters between the polymer and salt molecule,
and the polymer and water molecule have been computed using the experimental activity of water data in aqueous polymer solutions.
The results showed that the proposed model, segment-based Wilson and segment-based NRTL models have good accuracy in correlating
the vapor-liquid phase equilibria of the water-polymer and water-polymer-salt systems.
Also, the liquid-liquid phase behavior of the polymer-salt aqueous two-phase systems has been correlated using the proposed
model. The results show that the proposed model can more accurately correlate the phase behavior of aqueous two-phase systems
than the UNIQUAC and the modified Wilson models. 相似文献
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