Sharif Digital Repository

Hereby, a sonochemical method for synthesis of pure magnetic Fe3O4Onanoparticles (Fe3O4-NPs) in large scale is being introduced. Synthesis proceeds via simple approach, at room temperature, under sonication, using cheap reagents, green antioxidant-reductant reagent and without using inert gas purge as protective atmosphere condition. During this procedure, hydrogen gas releases continuously as valuable byproduct at the anaerobic step of reaction. Characterizations' results indicate that the final product is pure spherical Fe3O4-NPs, with narrow size distribution and about less than 32nm in mean diameter while more than 99% of particles size were less than 40nm. According to Vibrational... 

A manganese(III) complex, [Mn(phox)2(CH3OH) 2]ClO4 (phox = 2-(2′-hydroxyphenyl)oxazoline), was immobilized on silica-coated magnetic Fe3O4 nanoparticles through the amino propyl linkage using a grafting process in dichloromethane. The resulting Fe3O4@SiO2-NH2@Mn(III) nanoparticles are used as efficient and recyclable catalysts for selective oxidation of thiols to disulfides using urea-hydrogen peroxide as the oxidant. The nanocatalyst was recycled several times. Leaching and recycling experiments revealed that the nanocatalyst can be recovered, recycled, and reused more than five times, without the loss of catalytic activity and magnetic properties. The recycling of the nanocatalyst in six... 

Di-(2-ethylhexyl) phosphoric acid coated silanized magnetite nanoparticles were applied for the rapid removal and fast adsorption of molybdenum ions from simulated nitric acid solutions. The characterization of the developed adsorbent was carried out using various analytical techniques such as Transmission electron microscopy (TEM), X-ray diffraction pattern (XRD) and Fourier transform infrared spectroscopy (FT-IR). The Transmission electron microscopy photographs showed that the silanized magnetite nanoparticles were roughly spherical in shape and the average size of these particles is very close to the average size of bare magnetite particles. The binding of silane polymer and... 

Oxoperoxo tungsten(VI) complex immobilized on Schiff base-modified Fe3O4 super paramagnetic nanoparticles were synthesized and appropriately characterized using FT-IR, XRD, SEM, TEM, EDX, BET, and VSM analysis. The synthesized nanoparticles efficiently catalyzed oxidation of benzylic alcohols with H2O2 as oxidant in high yields, with high to excellent selectivity. The catalyst can be recovered using an external magnetic field and recycled for subsequent oxidation reactions without any appreciable loss of efficiency. The simple preparation, high activity, excellent selectivity, and simple recoverability of the catalyst are advantageous. © 2016 Informa UK Limited, trading as Taylor & Francis... 

In this research, an efficient biosorption system was developed for methylene blue adsorption over in situ hydrothermally synthesized magnetite 4-hydroxybenzoic acid cellulose nanohybrid. The material was characterized with EDX, VSM, FT-IR, FESEM, and TEM techniques. Results showed that the nanohybrid is a micro-cluster composed of stacked nanoscale particles. Multivariate optimization with Box–Behnken design was used to evaluate effective parameters on adsorption and their interaction. Results showed that pH, shacking time, and adsorbent dosage are effective parameters on MB adsorption. Adsorption rate is fast with equilibrium time of 5.5 min. Isotherm study revealed that the adsorption... 

In this research, an efficient biosorption system was developed for methylene blue adsorption over in situ hydrothermally synthesized magnetite 4-hydroxybenzoic acid cellulose nanohybrid. The material was characterized with EDX, VSM, FT-IR, FESEM, and TEM techniques. Results showed that the nanohybrid is a micro-cluster composed of stacked nanoscale particles. Multivariate optimization with Box–Behnken design was used to evaluate effective parameters on adsorption and their interaction. Results showed that pH, shacking time, and adsorbent dosage are effective parameters on MB adsorption. Adsorption rate is fast with equilibrium time of 5.5 min. Isotherm study revealed that the adsorption... 

The magnetic response of a polyamide nanocomposite membrane under applying a magnetic field has been modeled to evaluate elastic deformation order of magnitude. A PA-Fe3O4 nanocomposite membrane is considered to be modeled under influence of volume plane stress caused by a magnetic field. The modeling of the mechanical behavior of Fe3O4-PA nanocomposite membrane suggests that nanoparticle displacements within the nanocomposite, in the order of 200 nm under applying an external magnetic field, are greater than free volumes or porosities of the polyamide membrane. The membrane can be excited to mechanically vibrate by applying an alternating magnetic field lower than 0.1 T. As the results... 

The present research was aimed at simultaneous increase in strength and fracture energy of friction stir spot weld of Al-5083 alloy via reinforcing by Fe3O4 nanoparticles. Compared to non-reinforced welds, failure load and fracture energy of reinforced welds increased up to ∼115 and 560%, respectively. These findings were discussed in the light of grain refinement as well as considerable increase in hardness of fracture location due to the presence of sub-micron and nano reinforcing particles (RPs). Fe3O4 nanoparticles were transformed to Al–Fe intermetallics due to their small size and heat generated during the welding process. The stir zone of reinforced welds consisted of three different... 

We synthesized by electrostatic self-assembly route in basic solution Fe3O4–cysteine/RGO and Fe3O4/RGO–cysteine nanocomposites. In this method, electrostatic interaction was created via negatively charged surface of the reduced graphene oxide and reduced graphene oxide–cysteine sheets and positively charged surface of the Fe3O4 and Fe3O4–Cys nanoparticles in aqueous solution. The structural and magnetic properties of the prepared samples were analyzed by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), respectively. The dependences of magnetization as a function of... 

In this study Fe3O4/CMC magnetic nanoparticles were synthesized through co-precipitation method. Afterward, laccase from Trametes hirsuta was immobilized onto Carboxymethyl cellulose (CMC)-coated magnetic Fe3O4 nanoparticles by covalent bonding between carboxyl groups of carboxymethyl cellulose and amine group of laccases. Also, the resulted magnetic nanoparticles and immobilized laccase were characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and dynamic light scattering (DLS) analysis. Moreover, the vital factors in enzyme immobilization, such as contact time, amount of N-hydroxysuccinimide (NHS), and the amount of nanoparticles were... 

Molecular imaging (MI) can provide not only structural images utilizing temporal imaging techniques, but also functional and molecular data using a variety of newly developed imaging techniques. Nanotechnology’s application in MI has commanded a lot of attention in recent decades, and it has provided tremendous potential for imaging living subjects. In this study, D-glucosamine conjugated functionalized magnetic iron oxide nanoparticles (Fe3O4-PEG-DG NPs) were prepared and studied as magnetic resonance imaging (MRI) contrast agents. To evaluate their distribution, single-photon emission computed tomography (SPECT) is performed. Fe3O4 NPs are made using a well-known co-precipitation process... 

An extracting medium based on chitosan-polypyrrole (CS-PPy) magnetic nanocomposite was synthesized by chemical polymerization of pyrrole at the presence of chitosan magnetic nanoparticles (CS-MNPs) for micro-solid phase extraction. In this work, magnetic nanoparticles, the modified CS-MNPs and different types of CS-PPy magnetic nanocomposites were synthesized. Extraction efficiency of the CS-PPy magnetic nanocomposite was compared with the CS-MNPs and Fe3O4 nanoparticles for the determination of naproxen in aqueous samples, via quantification by spectrofluorimetry. The scanning electron microscopy images obtained from all the prepared nanocomposites revealed that the CS-PPy magnetic... 

A new method for the fabrication of an electromagnetic nanocomposite based on Fe3O4 and polyaniline (PANI) is offered. The authors focused on improvement of the physical and electromagnetic properties of the nanocomposite using a new synthetic method. Supermagnetic Fe3O4 nanoparticles were synthesized through coprecipitation method. As a chemical modification, the third generation of poly (amidoamine) dendrimer was grafted on the surface of the nanoparticles. PANI was grafted from -NH2 functional groups of dendrimer via in situ polymerization of aniline. Finally, Au nanoparticles were loaded on the nanocomposite and its catalytic activity for reduction reactions was studied  

In the past few years, laser-assisted methods have greatly influenced biomedical studies due to less invasive ways of treatment and higher precision. New stimuli-responsive drug carriers are still explored by scientists to achieve a better spatiotemporal control of drug carriers by using visible to NIR light instead of phototoxic ultra-violet irradiation. Due to their biocompatibility and high loading capacity of hydrophilic drugs, hydrogels have been used extensively in this area. However, poor cellular uptake and restricted loading of hydrophobic drugs are challenges that should be addressed. In this study, a previously known nanogel system based on chitosan and poly(N-isopropylacrylamide)... 

Ternary mesoporous nanocomposites of RGO/Fe3O4-ZnO were prepared successfully via hydrothermal technique. Fe3O4-ZnO core/shell nanoparticles were decorated on the surface of reduced graphene oxide platelet to improve charge separation efficiency and magnetic properties. The phase, microstructure and specific surface area of the prepared samples were determined via X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy/selected area electron diffraction (TEM/SAED) and Brunauer–Emmett–Teller (BET) techniques. A vibrating sample magnetometer (VSM) was used for recording the magnetization hysteresis curves. The methylene blue (MB)... 

Chondroitinase ABCI (cABCI) is a drug enzyme that can be used to treat spinal cord injuries. Due to low thermal stability of cABCI, this enzyme was immobilized on Fe3O4 nanoparticle to increase its thermal stability. The size and morphology, structure and magnetic property of the Fe3O4 nanoparticles were characterized by the analyses of SEM, XRD and VSM, respectively, and FTIR spectroscopy was employed to confirm the immobilization of cABCI on the surface of Fe3O4 nanoparticles. The results indicated that the optimum conditions for pH, temperature, cABCI-to-Fe3O4 mass ratio and incubation time in immobilization process were 6.5, 15 °C, 0.75 and 4.5 h, respectively, and about 0.037 mg cABCI... 

Magnetically separable inorganic-organic hybrid material H 5PW10V2O40/pyridino-Fe 3O4 (HPA/TPI-Fe3O4) nanoparticles provide an efficient and economic route for the synthesis of substituted bis(indolyl)methanes by the electrophilic substitution of indole with various aldehydes and ketones under solvent-free conditions with excellent yields in <30 min. This catalyst was prepared by the chemically anchoring H 5PW10V2O40 onto Fe3O 4 nanoparticles via the use of N-[3-(triethoxysilyl)propyl] isonicotinamide (TPI) linker. High catalytic activity and ease of recovery using an external magnetic field are additional eco-friendly attributes of this new catalytic system. The catalyst was recycled at... 

Polyvinylidene fluoride magnetic nanocomposite films were prepared by solution casting using two types of magnetic nanoparticles: (a) magnetic nanoparticles synthesized by co-precipitation method using oleic acid as a coating agent and (b) Fe3O4 nanoparticles prepared by hydrolysis method without using a coating agent. Dynamic light scattering measurements showed mean diameters of 135 and 46 nm in co-precipitation and hydrolysis methods, respectively. Scanning electron microscopy showed that the magnetic nanoparticles were uniformly dispersed inside the polymer matrix. X-ray diffraction confirmed that Fe3O4 nanoparticles induced nucleation of β- crystalline phase in the matrix polymer. The... 

Magnetite nanoparticles (mean particle size ranging from 10 to 20 nm) were prepared by a biomoleculeassisted solution-phase approach under ultrasonic irradiation. Cysteine was used as the capping agent in the solution. The results show that cysteine could be an efficient biocapping agent in producing Fe3O4 nanoparticles. The crystal structure and magnetic properties of the nanoparticles were characterized by XRD and VSM techniques, respectively. FT-IR was used to investigate the presence of cysteine on the nanoparticles surface. The influence of pH value of the solution on the size distribution and hydrodynamic size of nanoparticles were studied by TEM and DLS methods, respectively. The MTT... 

A new facile, rapid, inexpensive, and sensitive method based on magnetic micro-solid phase extraction (M-μ-SPE) coupled to gas chromatography-mass spectrometry (GC-MS) was developed for determination of the herbicide oxadiargyl in environmental water samples. The feasibility of employing non-modified magnetic nanoparticles (MNPs) as sorbent was examined and applied to perform the extraction process. Influential parameters affecting the extraction efficiency along with desorption conditions were investigated and optimized. The limit of detection (LOD, S/N = 3) and limit of quantification (LOQ, S/N = 10) of the method under optimized conditions were 0.005 and 0.030 ng mL-1, respectively. The...