Magnetic Iron Oxide Particles Research Articles

Development of Oil-based Drilling Fluid using Iron Oxide Magnetic (Fe3O4) with Superior Properties Leading to Real Time Rheological Control

Magnetorheological fluids have the ability to exhibit a wide range of rheological properties when exposed to an external magnetic field. In this paper, an applicable oil-based magnetorheological drilling fluid is prepared using iron oxide magnetic particles (Fe3O4). In order to prove the ability and performance of the prepared fluid, vibrating sample magnetometer (VSM) and magnetorheology tests have been performed. VSM measurements showed that permeability and saturation magnetization are 0.1615 and 135.3017 emu/gr, respectively. This test generates the hysteresis curve of the sample which shows that the behaviour of this fluid is soft magnetism i.e. it is very sensitive and is easily magnetized by the application of very small magnetic fields. Furthermore, magnetorheology measurements were conducted for magnetic fields ranging from 0 to 0.1T and the measured values are compared with rheology tests of conventional drilling fluids. The results indicate a noticeable increase in apparent viscosity and shear rate. [Received: January 29, 2019; Accepted: June 17, 2019]

Synthesis and Characterization of Bi-Functional Poly (Acrylic Acid-Co-2-hydroxyethylmethacrylate) Coated Iron Oxide Magnetic Composite Particles

This paper covers the targetable magnetic iron oxide core and biodegradable, cost-effective, eco-friendly polymer shell considering their versatile and extensive use in various fields. In this work, poly (acrylic acid–co-2-hydroxyethylmethacrylate) [P (AA-co-HEMA)] magnetic composite polymer particles were synthesized by the method of two-stage solution polymerization in aqueous media. At first synthesis, the Fe3O4 particles by a traditional co-precipitation method and in the second stage occurs the formation of the polymer using acrylic acid (AA) as monomer and 2-hydroxyethyl methacrylate (HEMA) as co-monomer. Finally, the synthesized iron oxide particles encapsulated by a polymer to modify the surface of composite particles. The modified composite particles were then characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffractometry (XRD), Dynamic Light Scattering (DLS), Thermo Gravimetric Analysis (TGA) and Vibrating Sample Magnetometry (VSM). The existence of carboxyl (-COOH) & hydroxyl (-OH) groups in the composite particles was confirmed by FTIR. XRD indicated the crystalline cubic spinel structure of magnetic composite particles. VSM results showed that the synthesized coated composite particles were paramagnetic in nature magnetic saturation is obtained 72.72 emu/g and 97.9 emu/g for bare Fe3O4 and coated magnetic composite particles respectively.

Magnetization of active inclusion bodies: comparison with centrifugation in repetitive biotransformations

BackgroundPhysiological aggregation of a recombinant enzyme into enzymatically active inclusion bodies could be an excellent strategy to obtain immobilized enzymes for industrial biotransformation processes. However, it is not convenient to recycle “gelatinous masses” of protein inclusion bodies from one reaction cycle to another, as high centrifugation forces are needed in large volumes. The magnetization of inclusion bodies is a smart solution for large-scale applications, enabling an easier separation process using a magnetic field.ResultsMagnetically modified inclusion bodies of UDP–glucose pyrophosphorylase were recycled 50 times, in comparison, inclusion bodies of the same enzyme were inactivated during ten reaction cycles if they were recycled by centrifugation. Inclusion bodies of sialic acid aldolase also showed good performance and operational stability after the magnetization procedure.ConclusionsIt is demonstrated here that inclusion bodies can be easily magnetically modified by magnetic iron oxide particles prepared by microwave-assisted synthesis from ferrous sulphate. The magnetic particles stabilize the repetitive use of the inclusion bodies .

Polymeric‐hydrogel‐coated iron oxide magnetic particles for efficient solvent dehydration

ABSTRACTIn this article, we report the synthesis of crosslinked polyacrylamide‐hydrogel‐coated iron oxide (Fe3O4–PAM) magnetic nanoparticles as a kind of novel and efficient solvent‐dehydrating agent. With the use of commercially available toluene (containing trace water at 168–173 ppm) as a model organic solvent, an excellent dehydration performance of Fe3O4–PAM was observed; trace water as low as 48 ppm was efficiently removed, and this desiccant could compete with respect to the dehydration efficiency with common sodium treatments. To our knowledge, this is the first example of the application of such water‐swollen hydrogel‐coated Fe3O4 magnetic nanoparticles for the efficient removal of trace water in solvents. Also, the Fe3O4–PAM magnetic nanoparticles could be easily separated from the solvents after the dehydration treatment; thus, they possess a great advantage over traditional organic solvent dry methods and may find a variety of applications, for example, in oil dehydration and organic solvent drying. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46869.

Specific Detection of Proteins Using Exceptionally Responsive Magnetic Particles.

Sensitivity and specificity are among the most important parameters for viable sensor technologies based on magnetic nanoparticles. In this work, we describe synthetic routes and analytical approaches to improve both aspects. Magnetic iron oxide particles having diameters of 120, 440, and 700 nm were synthesized, and their surfaces were specifically functionalized. The larger particles showed significantly stronger magnetic signals and responses when compared to commercially available magnetic particles (Dynabeads). A force-based detection method was used to distinguish specifically bound particles (via protein interactions) and nonspecifically bound ones (e.g., via physisorption). In addition, an exchange platform, denoted as exchange-induced remnant magnetization (EXIRM), was developed and utilized to detect label-free proteins specifically. Using EXIRM, the 700 nm magnetic particles showed a 7-fold increase in detection sensitivity when compared to the markedly larger commercially available Dynabeads; furthermore, EXIRM exhibited high specificity, even in a 100-fold increase of nontargeted protein. More generally, particle size effects, reaction times, and dynamic ranges are evaluated and discussed herein.

Development of bark-based magnetic iron oxide particle (BMIOP), a bio-adsorbent for removal of arsenic (III) from water.

Novel low-cost bark-based magnetic iron oxide particles (BMIOPs) were synthesized and investigated for the removal of As(III) in drinking water. The synthesized BMIOP had a saturation magnetization value of 38.62emug-1 which was found to be enough for the magnetic separation of exhausted BMIOP after As(III) adsorption. Parameters like agitation speed, adsorbent dosage, contact time, pH, temperature, and initial concentration were thoroughly investigated. Langmuir, Freundlich, and Dubinin-Radushkevich isotherms were used for the modeling of experiments and observed a maximum adsorption (19.61mgg-1) of As(III) by Langmuir isotherm. Kinetics of As(III) sorption were well correlated with the coefficients in pseudo-first-order than the pseudo-second-order rate equation. Thermodynamic parameter investigation revealed that As(III) sorption process is endothermic, feasible, and spontaneous. BMIOP emerged as less expensive adsorbent for the abatement of arsenic ion from the drinking water. BMIOP showed 13.58mgg-1 adsorption capacity when As(V) alone is present, while it is 9.43 and 7.04mgg-1 for As(V) and As(III), respectively, when present together in the water. Graphical Abstract ᅟ.

A novel method for sensitive, low-cost and portable detection of hepatitis B surface antigen using a personal glucose meter

Hepatitis B virus (HBV) infection is the major public health problem leading cause of death worldwide. The most important diagnostic marker for this infection is hepatitis B surface antigen (HBsAg). In this study, a novel, inexpensive, portable and sensitive ELISA method was designed and investigated for diagnosis of HBsAg based on the functionalized Fe3O4 and Al2O3 nanoparticles, with the strategy for detecting the concentration of glucose using a cheap and accessible personal glucose meter (PGM). The ELISA system was constructed using hepatitis B antibody against HBsAg immobilized on streptavidin coated magnetic iron oxide particles (S-Fe3O4) as the capture antibody (Ab1). In addition, another hepatitis B antibody against different epitope of HBsAg (Ab2) and glucoamylase both were immobilized on Al2O3 nanoparticles. After formation of the sandwich immune complex between Ab1 and Ab2 immobilized on S-Fe3O4 and Al2O3 NPs, respectively, through HBsAg, starch was converted into glucose using glucoamylase. Then, the glucose concentration was measured using PGM. The concentration of HBsAg was calculated based on the linear relation between the concentrations of HBsAg and glucose. Under optimal conditions, this assay showed detection limit values of 0.3 to 0.4 ng ml−1 for “ay” and “ad” subtypes of HBsAg, respectively. The results indicate that the designed assay is comparable to the commercial kits in terms of sensitivity, on-site, specificity, cost, simplicity, portability and reproducibility. The presented method can be used in disadvantaged areas of the world and blood transfusion centers. To the best of our knowledge, this is the first report of using PGMs for HBSAg detection.

Trace metals and magnetic particles in PM2.5: Magnetic identification and its implications

Magnetic measurement was combined with geochemical analysis to investigate the trace metal pollution of PM2.5. The study was carried out in Nanjing, China, where the average PM2.5 concentrations in summer and winter in 2013–2014 were 66.37 and 96.92 μg/m3, respectively. The dominant magnetic mineral in PM2.5 had a low-coercivity pseudo-single domain and consisted of magnetite and hematite. Iron-oxide magnetic particles comprised spherical as well as angular particles. Stable Pb isotopic ratio determinations showed that Pb in summer samples derived from coal emissions while the main sources of winter samples were smelting industry and coal emissions. The magnetic properties of the particles correlated strongly with trace metals derived from anthropogenic activities, such as industrial emission, coal combustion, and traffic vehicle activities, but poorly with those derived from natural sources. In the multiple linear regression analysis, Cr and Fe had higher correlation coefficients (training R > 0.7) in contrast to the low training R of As, Cd, Ni, Sr, and Ti (<0.5) determined using the PM2.5 concentrations and magnetic parameter values as the decision variables. Our results support the use of environmental magnetism determinations as a simple and fast method to assess trace metals in urban particulate matter.

Highly Efficient Removal of Silver-Containing Nanoparticles in Waters by Aged Iron Oxide Magnetic Particles

Methods for the removal of silver nanoparticles (AgNPs) and their transformation products, silver-containing nanoparticles (AgCNPs), are important, because of their potential risks to the general population and the environment. In this study, aged iron oxide magnetic particles (IOMPs) were synthesized by a simple solvothermal reaction and used for the removal of AgCNPs. The prepared IOMPs exhibit a high adsorption capacity toward AgCNPs in aqueous medium. Kinetic studies indicated that the adsorption of AgCNPs is a pseudo-second-order process. The experimental data for the adsorption of AgCNPs follow the Langmuir isotherm model, and their maximum adsorption capacities were 19.9–62.8 mg/g at pH 6.2 and 298 K. The sorption mean free energy calculated by the Dubinin–Radushkevich isotherm was 4.09–5.17 kJ/mol, indicating the occurrence of physisorption, which was mainly due to the electrostatic interactions. The IOMP adsorbents maintained high removal efficiencies after four cycles of adsorption–desorption, s...

Polyamine-modified magnetic graphene oxide nanocomposite for enhanced selenium removal

Abstract A poly (allylamine)-modified magnetic graphene oxide (PAA-MGO) with a high adsorption capacity for selenium oxyanions was prepared by a simple and facile method at room temperature. Poly (allylamine) (PAA) and magnetic iron oxide particles were synthesized on graphene oxide (GO) by an EDC (N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide)/NHS (N-hydroxysuccinimde) reaction and co-precipitation, respectively. The chemical structure and physical properties of PAA-MGO were characterized by Fourier transform infrared spectroscopy, thermo gravimetric analysis, zeta potential measurement, X-ray photoelectron spectroscopy, transmission electron microscopy, and magnetic hysteresis tests. Under external magnetic field, PAA-MGO was separated from solution within 5 min. The adsorption capacity of PAA-MGO nanocomposite at pH 5.8 is 120.1 mg/g for Se (IV) and 83.7 mg/g for Se (VI), respectively, which is not only much higher than GO and MGO, but also higher than most adsorbents reported in literature. The adsorption isotherms fit well with Freundlich model for Se (IV) and Se (VI) indicating multilayer adsorption on the rough surface of PAA-MGO. The high adsorption efficiency of PAA-MGO could be attributed to high surface area of GO matrix, active sites of iron oxide and positively charged amine groups. At 30 min, the selenium adsorption on PAA-MGO reaches 90% of the equilibrium for Se (IV) and 93% of the equilibrium for Se (VI). The pH effect on Se adsorption indicates that acidic pH benefits selenium adsorption on PAA-MGO, and the maximum adsorption capacities of PAA-MGO nanocomposite for Se (IV) and Se (VI) were both achieved at pH 3.1. The adsorbed selenium was stripped off at alkaline pH. The mechanism study illustrates that the enhanced selenium removal by PAA-MGO is attributed to dual interactions including ligand exchange between surface hydroxyl group of iron oxide and Se oxyanions, and electrostatic interaction between amine and Se oxyanions. Since PAA-MGO composite show near complete (over 99.3% for Se (IV) and 99.7% for Se (VI)) removal within 2 ppb for both Se oxyanions, it is practically usable for Se separation from wastewater.

The enhanced MR performance of dimorphic MR suspensions containing either magnetic rods or their non-magnetic analogs

A co-precipitation method was used to prepare non-magnetic rod-like ferrous oxalate dihydrate (Fe2CO4 · 2H2O) particles that were further turned into iron oxide (Fe3O4) magnetic rod-like particles. A simple precursor-assisted thermal decomposition technique enabled the preservation of the morphology and size of the precursor ferrous oxalate dihydrate particles, thus allowing their magnetic analogs to be obtained. Both types of rod-like particles were used as an additive together with spherical carbonyl iron (CI) particles in novel dimorphic magnetorheological (MR) suspensions. Controlled shear rate mode experiments were performed using a rotational rheometer with a source of an external magnetic field in order to investigate their MR behavior. Moreover, the properties of the novel prepared dimorphic MR (DMR) suspensions were compared with conventional MR suspensions based on spherical CI microparticles. It was found that the DMR suspensions exhibit enhanced MR performance as well as enhanced sedimentation stability in comparison with the MR suspension based on pure CI. The dimorphic suspensions containing magnetic rod-like additives further exhibited significant MR hardening at low shear rates. The properties of CI-based suspensions can be thus optimized by using various additive substances.

Synthesis and characterization of cationic lipid coated magnetic nanoparticles using multiple emulsions as microreactors

The aim of this study was to develop a novel iron oxide nanoparticle synthesis method with in-situ surface coating. For this purpose multiple emulsions were used as microreactors for the first time and magnetic iron oxide particles synthesized in the core of cationic solid lipid nanoparticles. DLS, SEM, TEM, VSM, Raman Spectrometer, XRD, and XPS techniques were performed for characterization of the magnetic nanoparticles. Obtained magnetic nanoparticles are superparamagnetic and no additional process was needed for surface adjustments. They are positively charged as a result of cationic lipid coating and has appropriate particle size (<30nm) for drug or nucleic acid delivery. Structure analysis showed that magnetic core material is in the form of magnetite. Saturation magnetization value was measured as 15–17emug−1 for lipid coated magnetic nanoparticles obtained by multiple emulsion method which is reasonably sufficient for magnetic targeting.

Preparation of Highly Cross-linked Magnetic Polymer Composite Particles and Application in the Separation of Arsenic from Water

Iron oxide magnetic particles have become a promising research field in separation technology because of their easy separation by external magnetic field and can be applied for the removal of toxic metals from waste water. Highly cross-linked Fe3O4/P(S-DVB) particles were prepared in this research by suspension polymerization of styrene (S) and divinylbenzene (DVB) in presence of nanosized Fe3O4 particles. At first Fe3O4 nanoparticles were prepared by co-precipitation of Fe2+ and Fe3+ from their alkaline aqueous solution. To stabilize the magnetic particles, the surface of the particles was modified with oleic acid. The morphology and surface structure were characterized by Fourier Transform IR(FTIR), Transmission Electron Microscope (TEM), Scanning Electron Microscope(SEM), and light microscope.The adsorption behavior of As(III) on composite polymer particles was evaluated and a comparative study with reference copolymer particles revealed that composite polymer particles possessed better adsorption capacity.

Sensitive magnetic biodetection using magnetic multi-core nanoparticles and RCA coils

We use functionalized iron oxide magnetic multi-core particles of 100nm in size (hydrodynamic particle diameter) and AC susceptometry (ACS) methods to measure the binding reactions between the magnetic nanoparticles (MNPs) and bio-analyte products produced from DNA segments using the rolling circle amplification (RCA) method. We use sensitive induction detection techniques in order to measure the ACS response. The DNA is amplified via RCA to generate RCA coils with a specific size that is dependent on the amplification time. After about 75min of amplification we obtain an average RCA coil diameter of about 1µm. We determine a theoretical limit of detection (LOD) in the range of 11 attomole (corresponding to an analyte concentration of 55 fM for a sample volume of 200µL) from the ACS dynamic response after the MNPs have bound to the RCA coils and the measured ACS readout noise. We also discuss further possible improvements of the LOD.

Fabrication of core-shell Fe3O4@MIL-100(Fe) magnetic microspheres for the removal of Cr(VI) in aqueous solution

Facile regeneration of an adsorbent is very important for commercial feasibility. One typical highly porous metal-organic framework (MOF) materials based on MIL-100(Fe) and magnetic iron oxide particles (denoted as MMCs) with diameter about of 350 nm were successfully synthesized. The growth of MIL-100(Fe) shell on the surface of Fe3O4 was utilized precursor as crystal seed via in-situ step hydrothermal reaction. It is a simple way to obtain well organized core-shell MOF composites, compared to the step-by-step method. MMCs were firstly used to uptake of Cr(VI) anions in aqueous solution. Adsorption experiments were carried out in batch sorption mode investigating with the factors of contact time (0–1000min), pH (from 2 to 12), dose of adsorbent (4–25mg), and initial Cr(VI) concentration (range from 10 to 100ppm).

Disease-Homologous Mutation in the Cation Diffusion Facilitator Protein MamM Causes Single-Domain Structural Loss and Signifies Its Importance.

Cation diffusion facilitators (CDF) are highly conserved, metal ion efflux transporters that maintain divalent transition metal cation homeostasis. Most CDF proteins contain two domains, the cation transporting transmembrane domain and the regulatory cytoplasmic C-terminal domain (CTD). MamM is a magnetosome-associated CDF protein essential for the biomineralization of magnetic iron-oxide particles in magnetotactic bacteria. To investigate the structure-function relationship of CDF cytoplasmic domains, we characterized a MamM M250P mutation that is synonymous with the disease-related mutation L349P of the human CDF protein ZnT-10. Our results show that the M250P exchange in MamM causes severe structural changes in its CTD resulting in abnormal reduced function. Our in vivo, in vitro and in silico studies indicate that the CTD fold is critical for CDF proteins’ proper function and support the previously suggested role of the CDF cytoplasmic domain as a CDF regulatory element. Based on our results, we also suggest a mechanism for the effects of the ZnT-10 L349P mutation in human.

Decolorization of Methylene Blue by Persulfate Activated with FeO Magnetic Particles

In this study, the degradation of methylene blue (MB) was conducted to evaluate the feasibility of using persulfate oxidation activated with iron oxide (FeO) magnetic particles. The results demonstrated that the decolorization rate of MB increased with increasing FeO concentration, exhibiting maximum efficiency at pH0 3.0. The kinetics of MB was studied in the binary FeO catalyst and persulfate oxidation system. The surface properties of FeO before and after reaction was analyzed using cyclic voltammogram (CV), three-dimensional excitation-emission fluorescence matrix (EEFM) spectroscopy, zeta potential, particle size distribution measurements, X-ray diffraction (XRD) and environmental scanning electron microscopy-energy dispersive X-ray spectrometry (ESEM-EDS). The CV data indicated that a reversible redox reaction holds the key to explaining the significant activity of the catalyst. EEFM was used to evaluate the catalyst yield of FeO by fluorescence intensity plots with excitation/emission at 220/300 nm and 260/300 nm. The XRD and ESEM-EDS results confirmed the presence of FeO in the catalyst.

Magnetically modified biochar for organic xenobiotics removal

Large amounts of biochar are produced worldwide for potential agricultural applications. However, this material can also be used as an efficient biosorbent for xenobiotics removal. In this work, biochar was magnetically modified using microwave-synthesized magnetic iron oxide particles. This new type of a magnetically responsive biocomposite material can be easily separated by means of strong permanent magnets. Magnetic biochar has been used as an inexpensive magnetic adsorbent for the removal of water-soluble dyes. Five dyes (malachite green, methyl green, Bismarck brown Y, acridine orange and Nile blue A) were used to study the adsorption process. The dyes adsorption could be usually described with the Langmuir isotherm. The maximum adsorption capacities reached the value 137 mg of dye per g of dried magnetically modified biochar for Bismarck brown Y. The adsorption processes followed the pseudo-second-order kinetic model and the thermodynamic studies indicated spontaneous and endothermic adsorption. Extremely simple magnetic modification of biochar resulted in the formation of a new, promising adsorbent suggested for selected xenobiotics removal.

Magnetic modification of diamagnetic agglomerate forming powder materials

A simple method for the magnetic modification of various types of powdered agglomerate forming diamagnetic materials was developed. Magnetic iron oxide particles were prepared from ferrous sulfate by microwave assisted synthesis. A suspension of the magnetic particles in water soluble organic solvent (methanol, ethanol, propanol, isopropyl alcohol, or acetone) was mixed with the material to be modified and then completely dried at elevated temperature. The magnetically modified materials were found to be stable in water suspension at least for 2 months.

Recovery of Phosphate by Magnetic Iron Oxide Particles and Iron Oxide Nanotubes in Water

In this study, we focused on the performance of phosphate recovery in the case of magnetic iron oxide (MIO) particles and iron oxide nanotubes (INTs) with synthetic wastewater. MIO particles were prepared by a co-precipitation method, and INTs were prepared with a potentiostatic anodization method of zerovalent iron foil in electrolyte-containing sulfate and fluoride. Although MIO had the fast adsorption rate, INT had a higher adsorption capacity per surface area rather than MIO. The adsorption isotherm of MIO and INT was approximated by a Freundlich type. Phosphate adsorbed on MIO and INT was effectively desorbed with alkaline solutions. For phosphate recovery, MIO needs a magnetic recovery device, whereas, when INT was used for phosphate recovery, another recovery step is not necessary. Both methods showed effective adsorption performance for phosphate recovery in wastewater.