Search for: magnetite
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    Avrami behavior of magnetite nanoparticles formation in co-precipitation process

    , Article Journal of Mining and Metallurgy, Section B: Metallurgy ; Volume 47, Issue 2 , 2011 , Pages 211-218 ; 14505339 (ISSN) Ahmadi, R ; Hosseini, H. M. R ; Masoudi, A ; Sharif University of Technology
    In this work, magnetite nanoparticles (mean particle size about 20 nm) were synthesized via coprecipitation method. In order to investigate the kinetics of nanoparticle formation, variation in the amount of reactants within the process was measured using pH-meter and atomic absorption spectroscopy (AAS) instruments. Results show that nanoparticle formation behavior can be described by Avrami equations. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were performed to study the chemical and morphological characterization of nanoparticles. Some simplifying assumptions were employed for estimating the nucleation and growth rate of magnetite nanoparticles  

    Effect of concentration on hydrodynamic size of magnetite-based ferrofluid as a potential MRI contrast agent

    , Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; 2013 ; 09277757 (ISSN) Ahmadi, R ; Gu, N ; Sharif University of Technology
    In this work, ferrofluids containing dextran coated magnetite nanoparticles have been synthesized via co-precipitation method. FT-IR results verified presence of dextran molecules on the particles surface. TEM results showed that mean particle size is 7.23 nm, while mean hydrodynamic size determined via PCS technique varies between 39.8 and 125.8 nm depending on the ferrofluid concentration. The maximum hydrodynamic size was obtained in mid concentrations. To the best of our knowledge, effect of concentration on mean hydrodynamic size has not been systematically studied before. VSM results confirmed the superparamagnetic behavior of the synthesized nanoparticles with saturation magnetization... 

    A new approach for calculation of relaxation time and magnetic anisotropy of ferrofluids containing superparmagnetic nanoparticles

    , Article Journal of Mining and Metallurgy, Section B: Metallurgy ; Volume 48, Issue 1 , 2012 , Pages 81-88 ; 14505339 (ISSN) Ahmadi, R ; Hosseini, H. R. M ; Sharif University of Technology
    In this work, a new approach is described for the calculation of the relaxation time and magnetic anisotropy energy of magnetic nanoparticles. Ferrofluids containing monodispersed magnetite nanoparticles were synthesized via hydrothermal method and then heated using the 10 kA/m external AC magnetic fields in three different frequencies: 10, 50 and 100 kHz. By measuring the temperature variations during the application of the magnetic field, the total magnetic time constant including both Brownian and Neel relaxation times can be calculated. By measuring the magnetic core size and hydrodynamic size of particles, the magnetic anisotropy can be calculated too. Synthesized ferrofluids were... 

    Microemulsion Synthesize of Fe3O4/TiO2 Core-Shell Nanoparticles

    , M.Sc. Thesis Sharif University of Technology Sonbolestan, Hosein (Author) ; Madaah Hoseini, Hamid Reza (Supervisor)
    In this study magnetite nanoparticles were synthesized by microemulsion and were coated with TiO2 by a precipitation technique. The synthesize process were done under fixed molar ratio of various constituents of microemulsion and molar ratio of water to oil. Results of X-ray diffraction spectroscopy (XRD) showed that the uncoated nanoparticles were consisted of magnetite as the major phase and no other detectable phases such as pure iron or hematite were found. Field emission scanning electron microscopy (FE-SEM) results showed that the synthesized nanoparticles small size and narrow particle size distribution. For TiO2 coating process the effect of TBOT concentration, water concentration,... 

    Fabrication of Fe-oxide@Silica@Gold (core/shell/shell) in Order to Development of Biomarkers

    , M.Sc. Thesis Sharif University of Technology Mohammad-Beigi, Hossein (Author) ; Yaghmaei, Soheyla (Supervisor) ; Arpanaei, Ayyoob (Supervisor) ; Roosta Azad, Reza (Co-Advisor)
    The aim of this work is fabrication of magnetite@silica@gold particles. Study of the effect of pH showed that increasing pH from 9 to 12 resulted in a decrease in the size of magnetite nanoparticles from 7.9±1.38 nm to 5±0.64 nm. The TEM results indicated that modifying magnetic nanoparticles with sodium citrate prior to coating with silica leads to a narrow particle size distribution (275±16.1nm) and less number of silica nanoparticles without any magnetite core. Three methods were applied for attachment of gold nanoparticles seeds onto the silica surface: 1) use of an electrostatic interaction between positively-charged aminated silica and negatively-charged gold nanoparticles surfaces, 2)... 

    Glass-ceramics for cancer treatment: So close, or yet so far?

    , Article Acta Biomaterialia ; 2018 ; 17427061 (ISSN) Miola, M ; Pakzad, Y ; Banijamali, S ; Kargozar, S ; Vitale Brovarone, C ; Yazdanpanah, A ; Bretcanu, O ; Ramedani, A ; Vernè, E ; Mozafari, M ; Sharif University of Technology
    After years of research on the ability of glass-ceramics in bone regeneration, this family of biomaterials has shown revolutionary potentials in a couple of emerging applications such as cancer treatment. Although glass-ceramics have not yet reached their actual potential in cancer therapy, the relevant research activity is significantly growing in this field. It has been projected that this idea and the advent of magnetic bioactive glass-ceramics and mesoporous bioactive glasses could result in major future developments in the field of cancer. Undoubtedly, this strategy needs further developments to better answer the critical questions essential for clinical usage. This review aims to... 

    Kinetics of magnetite nanoparticles formation in a one step low temperature hydrothermal process

    , Article Ceramics International ; Volume 39, Issue 5 , July , 2013 , Pages 4999-5005 ; 02728842 (ISSN) Ahmadi, R ; Masoudi, A ; Madaah Hosseini, H. R ; Gu, N ; Sharif University of Technology
    In the present study, a one step hydrothermal process was employed to synthesize magnetite nanoparticles using oleic acid as surfactant agent at 140 °C. Effects of reaction time and alkalinity were studied on particles size and morphology. By changing these parameters, some monodisperse spherical nanoparticles with mean particle size between 2.71 and 13.88 nm were synthesized and characterized via TEM, XRD, VSM, TGA and FT-IR techniques. Assuming the Avrami behavior of particles formation, a kinetics equation was proposed for the transformation rate at 140 °C. Using some simplifying assumptions, nucleation and growth rates were calculated for the hydrothermal formation of magnetite... 

    Comparison of different strategies for the assembly of gold colloids onto Fe3O4@SiO2 nanocomposite particles

    , Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 49 , 2013 , Pages 30-38 ; 13869477 (ISSN) Mohammad Beigi, H ; Yaghmaei, S ; Roostaazad, R ; Arpanaei, A ; Sharif University of Technology
    Three strategies were employed for the assembly of gold nanoparticles on silica-coated magnetite particles (SCMPs). In strategy I, citrate-coated gold nanoparticles were attached on the surface of amine-SCMPs. In strategy II, amine-SCMPs were coated with carboxylated gold nanoparticles via amide bond formation. In strategy III, the thiol-SCMPs surface was coated with gold nanoparticles. Among the above examined strategies, coating amine-SCMPs with gold nanoparticles via strategy I resulted in a better coverage and stronger intensity of absorption bands. Furthermore, results obtained through strategy I showed that decreasing the pH of the solution from 7 to 3 leads to a further red-shift of... 

    Targeted pulmonary drug delivery in coronavirus disease (COVID-19) therapy: A patient-specific in silico study based on magnetic nanoparticles-coated microcarriers adhesion

    , Article International Journal of Pharmaceutics ; Volume 609 , 2021 ; 03785173 (ISSN) Ebrahimi, S ; Shamloo, A ; Alishiri, M ; Mozhdehbakhsh Mofrad, Y ; Akherati, F ; Sharif University of Technology
    Elsevier B.V  2021
    Since the beginning of the COVID-19 pandemic, nearly most confirmed cases develop respiratory syndromes. Using targeted drug delivery by microcarriers is one of the most important noteworthy methods for delivering drugs to the involved bronchi. This study aims to investigate the performance of a drug delivery that applies microcarriers to each branch of the lung under the influence of a magnetic field. The results show that by changing the inlet velocity from constant to pulsatile, the drug delivery performance to the lungs increases by ∼31%. For transferring the microcarriers to the right side branches (LUL and LLL), placing the magnet at zero height and ∼30° angle yields the best outcome.... 

    Factors Affecting the Efficiency of Ferrite Process for Removal of Heavy Metals (Case study of Chromium and Nickel)

    , M.Sc. Thesis Sharif University of Technology Abdolshahinejad, Sara (Author) ; Borgheei, Mahdi (Supervisor)
    Heavy metals, present in many industrial wastewaters, are considered as major pollutants of environment. Various methods to removal heavy metals effectively from effluents have been used in industry, yet more efficient and economical methods are required. Magnetic iron nanoparticles are known for their superior adsorption, ion exchange and electro-static forces characteristics.The aim of this study was to evaluate the efficiency of magnetic nanoparticles for removal of hexavalent chromium (VI) and Divalent nickel from wastewater and the parameters that influence the removal.The magnetite nanoparticles were prepared by co-precipitation method where produced Fe3O4 nanoparticle’s average size... 

    Effect of Coprecipitation and Hydrothermal Parameters on the Properties of Ferrofluids Based on Magnetite Nanoparticles as MRI Contrast Agent

    , Ph.D. Dissertation Sharif University of Technology Ahmadi, Reza (Author) ; Madaah Hosseini, Hamid Reza (Supervisor)
    Ferrofluids are special stable suspensions of magnetic nanoparticles dispersed in liquid phase. These materials have numerous biological applications such as drug delivery, magnetic hyperthermia and magnetic resonance imaging due to their special magnetic properties and fluidity. Particle size and magnetic properties of ferrofluids have an important role in these applications. In this work, magnetite-based ferrofluids have been synthesized via coprecipitation and hydrothermal methods. In the coprecipitation process, cysteine and dextran surfactants have been used as ferrofluid stabilizer and effect of synthesize temperature, time, pH and surfactant concentration have been investigated on... 

    Synthesis and Characterization of Graphene-based Material and Investigation of its Adsorption Properties for Radioactive Waste

    , Ph.D. Dissertation Sharif University of Technology Tayyebi, Ahmad (Author) ; Outokesh, Mohammad (Supervisor)
    Nuclear power is a prominent alternative of fossil fuels that can effectively solve global warming, acid rains and other consequences of air pollutions, caused by combustion. Despite such obvious advantage, this highly compact form of energy suffers from a big problem corresponding to its nuclear waste. Graphene oxide (GO), a lamellar material with wide range of surface functional groups such as epoxy (C-O-C), hydroxyl, and carboxyl offers large surface area as well as high sorption capacity for the metallic cations. This thesis study presents a supercritical, and co-precipitation synthesis of magnetite- graphene oxide (M-GO) in which Fe3O4 nanoparticles are simultaneously formed, surface... 

    Solid phase extraction of trace amounts of Pb(II) in opium, heroin, lipstick, plants and water samples using modified magnetite nanoparticles prior to its atomic absorption determination

    , Article Journal of the Iranian Chemical Society ; Volume 9, Issue 2 , 2012 , Pages 171-180 ; 1735207X (ISSN) Karimi, M. A ; Hatefi Mehrjardi, A ; Mohammadi, S. Z ; Mohadesi, A ; Mazloum Ardakani, M ; Hormozi Nezhad, M. R ; Kabir, A. A ; Sharif University of Technology
    A new, simple, fast and reliable solid-phase extraction method has been developed for separation/preconcentration of trace amounts of Pb(II) using dithizone/sodium dodecyl sulfate-immobilized on alumina-coated magnetite nanoparticles, and its determination by flame atomic absorption spectrometry (FAAS) and graphite furnace atomic absorption spectrometry (GFAAS) after eluting with 4.0 mol L -1 HNO 3. Optimal experimental conditions including pH, sample volume, eluent concentration and volume, and co-existing ions have been studied and established. Under the optimal experimental conditions, the preconcentration factor, detection limit, linear range and relative standard deviation of Pb(II)... 

    Study the effect of ultrasonic irradiation and surfactant/fe ions weight ratio on morphology and particle size of magnetite nanoparticles synthesised by co-precipitation for medical application

    , Article World Academy of Science, Engineering and Technology ; Volume 64 , 2010 , Pages 457-460 ; 2010376X (ISSN) Azimipour Meibod, S. S ; Pourafshary, P ; Madaah Hosseini, H. R ; Sharif University of Technology
    A biocompatible ferrofluid have been prepared by coprecipitation of FeCl 2.4H 2O and FeCl 3.6H 2O under ultrasonic irradiation and with NaOH as alkaline agent. Cystein was also used as capping agent in the solution. Magnetic properties of the produced ferrofluid were then determined by VSM test and magnetite nanoparticles were characterized by XRD and TEM techniques. The effect of surfactant to Fe ion weight ratio was also studied during this project by using two different amount of Dextran. Results showed the presence of a biocompatible superparamagnetic ferrofluid including magnetite nanoparticles with particle size ranging under 20 nm. The increase in the surfactant content results in the... 

    Synthesis of Conductive Magnetite Nanocomposite based on Polyaniline/Poly(maleic acid-co-acrylic acid) with Core-Shell Structure

    , Article Advances in Polymer Technology ; 2016 ; 07306679 (ISSN) Khodadadi, F ; Najafi Moghadam, P ; Mahmoodi Hashemi, M ; Sharif University of Technology
    John Wiley and Sons Inc  2016
    In this study, a new type of magnetite nanocomposite with a core-shell structure was synthesized using Fe3O4 nanoparticles as a core and polyaniline (PANI) as a shell. For this propose, the surface of Fe3O4 was chemically modified with hexamethylenediisocyanate (HMDI) to improve its compatibility and interphase interaction with the polymeric matrix. Thereafter, the PANI was reacted with modified Fe3O4 to anchor them to PANI by covalent bands which acted as a shell. In the second step, the poly (maleic acid-co-acrylic acid) (P(MAc-co-AA)) as polymeric dopant for the PANI was synthesized. Finally, the PANI anchored to Fe3O4 was immersed in an aqueous solution of poly (maleic... 

    Investigation of the impact of synthesized hydrophobic magnetite nanoparticles on mass transfer and hydrodynamics of stagnant and stirred liquid–liquid extraction systems

    , Article Chemical Engineering Research and Design ; Volume 147 , 2019 , Pages 305-318 ; 02638762 (ISSN) Hatami, A ; Azizi, Z ; Bastani, D ; Sharif University of Technology
    Institution of Chemical Engineers  2019
    The impact of modified magnetite nanoparticles (MMNPs)on hydrodynamics and mass transfer in liquid–liquid extraction process was assessed using a ternary chemical system of toluene-acetic acid–water. The organic phase which contained toluene and acetic acid was dispersed through water, and the mass transfer of acetic acid between two phases was investigated. The hydrophobic modified magnetite nanoparticles (MMNPs)prepared through an optimized in-situ method were added to the dispersed phase at different concentrations (0.001−0.005 wt%). Two separate conditions were provided in the experiments, i.e. stagnant and stirred continuous phase. The latter case was provided by a rotor at two... 

    Kinetic of Partial Reduction of Hematite to Magnetite

    , M.Sc. Thesis Sharif University of Technology Azarbaijani, Zahra (Author) ; Halali, Mohammad (Supervisor)
    This research has studied the kinetic and mechanism of partial reduction of hematite to magnetite via carbon monoxide gas. In addition, temperature and partial pressure of CO gas as two main parameters which influence the rate of the reduction process has been studied. In order to investigate the change in mass during the reaction, thermogravimetric analysis (TGA) has been applied and in order to evaluate the effect of the temperature and partial pressure of CO on the rate of the reduction, three different temperatures and two different ratios of CO/CO2 has been experimented. Three isothermal analysis in 390°C, 440°C, and 490°C in pure CO atmosphere and two isothermal analysis in 550°C with... 

    Development of Magnetic Iron Oxide Nanoparticles Encapsulated in the Polymeric Matrix and its Applications in the Study of Radionuclides Uptake

    , M.Sc. Thesis Sharif University of Technology Esmailnia, Sahar (Author) ; Otukesh, Mohammad (Supervisor) ; Khanchi, Alireza (Supervisor)
    Nanoparticles have attracted the attention of many researchers because of the distinct physical and chemical properties. Besides the traditional applications in plastic reinforcement, fluid rheological additive, etc., the nanoparticles could be applied to many new fields and high-functional devices. Various chemical methods have been employed for the production of nanoparticles with narrow size distribution, such as co-precipitation, micro-emulsion, electrochemical synthesis, hydrothermal synthesis, sol–gel processing, flame spray pyrolysis, plasma chemical vapor deposition (CVD), hot-soap method and electrospray pyrolysis. But most of them have some problems so that only a few of them... 

    RSM based engineering of the critical gelation temperature in magneto-thermally responsive nanocarriers

    , Article European Polymer Journal ; Volume 120 , 2019 ; 00143057 (ISSN) Khodaei, A ; Bagheri, R ; Madaah Hosseini, H. R ; Bagherzadeh, E ; Sharif University of Technology
    Elsevier Ltd  2019
    The multistep release of therapeutic agents in the theranostic particulate systems has remained as a challenge in smart drug delivery. In this study, superparamagnetic nanoparticles of Fe3O4 were coated with a blend of F127/F68 grades of pluronic in order to adjust the lower critical solution temperature (LCST) and consequently engineering of the release temperature. Pluronic as a biocompatible thermo-sensitive polymer is frequently used as a self-emulsifying drug delivery system. Magnetite nanoparticles with double layer coating of oleic acid and pluronic F127 have been reported as an on-demand smart carrier for hydrophobic drugs. LCST was examined using differential scanning calorimetry... 

    Synthesis, characterization and catalytic activity of supported vanadium Schiff base complex as a magnetically recoverable nanocatalyst in epoxidation of alkenes and oxidation of sulfides

    , Article Journal of Organometallic Chemistry ; Volume 897 , 2019 , Pages 200-206 ; 0022328X (ISSN) Bagherzadeh, M ; Bahjati, M ; Mortazavi Manesh, A ; Sharif University of Technology
    Elsevier B.V  2019
    A new magnetically separable nanocatalyst was successfully synthesized by immobilizing of vanadyl acetylacetonate complex, [VO(acac)2], onto silica coated magnetite nanoparticles previously functionalized with 3-aminopropyltriethoxysilane (3-APTES) and reacted by 5-bromosalicylaldehyde to form Schiff base moiety. The obtained nanocatalyst was characterized by elemental analysis (CHN), FT-IR spectroscopy, Powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), inductively coupled plasma optical emission spectrometry (ICP-OES) and thermogravimetric analysis (TGA). Eventually, the resulting nanoparticles were used as catalyst for epoxidation of alkenes and...