Modified Magnetite Nanoparticles Research Articles

Removal of fine solids from bitumen by hetero-aggregation and magnetic separation using surface-modified magnetite nanoparticles. Part 2: Role of surface modification

Stearylamine acetate (SAA) modified magnetite nanoparticles (MNPs) have been previously proven to significantly improve the efficiency of fine solids removal from cyclohexane-diluted non-aqueous extracted (NAE) bitumen following magnetic separation. In this work, asphaltene-modified magnetite nanoparticles (Asp-MNPs) were prepared, and their ability to remove fine solids from NAE bitumen was evaluated. The influence of the surface modification with SAA or asphaltene on MNPs in their interactions with NAE fine solids was studied through quartz crystal microbalance with dissipation monitoring and atomic force microscopy studies. It was demonstrated that modification by SAA increased the adhesion interaction between the MNPs and NAE fine solids through a bridging effect. The use of an external magnetic field also strengthened the hetero-aggregation between surface-modified MNPs and the NAE fine solids. Though the asphaltene modification of MNPs resulted in a repulsive behavior in the interaction between MNPs and NAE fine solids due to steric effect, the applied external magnetic field could drive the Asp-MNPs together and induce the bridging among the Asp-MNPs through an interdigitation process, and the NAE fine solids could be captured through a sweeping effect by the networked Asp-MNPs.

Adsorption of Antibiotic Drug on the Surface of Humic Acid Modified Magnetite Nanoparticles: Kinetics, Isotherm and Thermodynamic Studies

The present study reports the synthesis of humic acid-modified magnetite nanoparticles for adsorption behaviour towards the ofloxacin drug. Several analytical and spectroscopic techniques were used to characterize the synthesized surface modified magnetite nanoparticles. In order to determine the highest possible adsorption capacity of these coated nanoparticles, the effects of various influencing variables such as pH of the solution, contact time, initial concentration of adsorbate solution, amount of adsorbent and temperature were also investigated using batch adsorption method. Adsorption isotherm and kinetic analysis for the adsorption of ofloxacin drug from aqueous solution were studied simultaneously. The kinetics and isotherm studies demonstrated good agreement with the pseudo-second-order kinetics model and Langmuir model of isotherm, respectively. Thermodynamic analysis of the adsorption of ofloxacin on the surface of humic acid modified magnetite nanoparticles displayed negative values of Gibb’s free energy change, positive values of enthalpy as well as entropy change, resulting that the adsorption process was spontaneous and endothermic in nature. A comparative study of percentage drug removal efficiency of humic acid functionalized magnetite nanoparticles with the reported adsorbents has also been reported. This study revealed that the humic acid-modified magnetite nanoparticles showed remarkable adsorption capacity and thus could be used as an effective adsorbent for the removal of ofloxacin from aqueous solution.

Immobilization of phosphotungstic acid on the surface of chemically modified magnetite nanoparticles: An efficient heterogeneous acid catalyst for alcoholysis of epoxides

A new magnetically recoverable heterogeneous acid catalyst was easily synthesized by electrostatic interaction of phosphotungstic acid (HPW) species with 3-aminopyridine (Ampy) modified magnetite-silica heterostructure (Fe3O4/SiO2-Ampy-HPW). The step by step modification of magnetite nanoparticles along with structural stability, and maintenance of magnetization and morphology of bare magnetite nanoparticles after chemical functionalization steps were confirmed by various physicochemical techniques. The size of these nanoparticles was obtained to be 10–30 nm from TEM analysis, which was in accordance with the data estimated from XRD technique. Also, it was observed that the presence of HPW on the surface of catalyst has increased the acid content of catalyst. Catalytic property of Fe3O4/SiO2-Ampy-HPW catalyst was assessed in acid-catalyzed ring opening of epoxides with alcohols. According to the results obtained at optimum reaction condition, the prepared catalyst exhibited good performance (conversion of 93%) with high selectivity (100%) in methanolysis of styrene oxide compared to the unfunctionalized Fe3O4/SiO2, which is definitely due to the presence of HPW acidic species on the surface of Fe3O4/SiO2. Moreover, other epoxides and alcohols were tested in this catalytic system, which subsequently, reasonable results with more or less conversion were obtained based on the types of the epoxides and alcohols used.

Poly(methacrylic acid) surface modified magnetite nanoparticles for dispersive solid-phase adsorption of chlorpyrifos pesticide from aqueous solutions

Poly(methacrylic acid) surface modified magnetite nanoparticles for dispersive solid-phase adsorption of chlorpyrifos pesticide from aqueous solutions

Modified magnetite nanoparticles synthesized using cetyltrimethylammonium bromide and their application to immobilize trypsin

This paper presents the study of the properties of immobilized trypsin from the bovine pancreas. Fe3O4 nanoparticles as magnetically detachable carriers were synthesized using surfactant cetyltrimethylammonium bromide (CTAB). CTAB allows for obtaining non-agglomerated nanosized particles with superparamagnetic properties. The support surface was functionalized with amino groups using (3–aminopropyl)triethoxysilane and next glutaraldehyde. Immobilization of trypsin was carried out by covalent binding of trypsin with modified magnetite. The activities of native and immobilized trypsin were measured using 1% casein. The effect of reuse at nine cycles on the activity of the immobilized trypsin was tested. The activity of immobilized trypsin on magnetite was studied during storage at 4 °C for 28 days. It was found that in optimal conditions at a temperature of 55 °C and pH 7.6. The Michaelis–Menten constant Km was 5.59 ± 0.37 mM and the maximum reaction rate vmax was 10.74 ± 1.85 mM min−1 for immobilized trypsin, compared to a Km of 4.63 ± 0.34 mM and a vmax of 8.74 ± 0.88 mM min−1 for free trypsin at a temperature of 37 °C. High activity of the immobilized trypsin during reusability, presents that immobilized trypsin might find potential application in practice.

Synthesis of Fe3O4nanoparticles encapsulated with orange pectin for the treatment of gastrointestinal cancers

The current work reports a unique bio-inspired synthesis of orange derived pectin modified magnetite nanoparticles (Fe3O4NPs). Pectin is a naturally occurring biopolymer containing plethora of polar organofunctions which are exploited in the toxic reagent free modification of biocompatible magnetic NPs and also towards the stabilization of NPs by preventing them from agglomeration. The physicochemical properties of the as-prepared bio-nanocomposite (Fe3O4@Pectin) was analytically investigated through SEM, EDX, TEM, VSM and XRD. The anti-gastrointestinal system cancers and cytotoxic potentials of synthesized NPs against cancer cell lines were assessed. The anti-gastrointestinal system cancers potentials of the NPscould significantly remove (HT-29, HCT 116, Ramos.2G6.4C10, HCT-8 (Colorectal cancer)), (Capan-2, AsPC-1, CFPAC-1, HPAF-II (Pancreatic cancer)), (GC1436, GC1401, AGS, and GC1415 (Gastric cancer)) cell lines by MTT assay. The corresponding IC50 were found as 13, 8, 16, 15, 11, 12, 15, 15, 23, 36, 30, and 23μg/mL against HT-29, HCT 116, Ramos.2G6.4C10, HCT-8, Capan-2, AsPC-1, CFPAC-1, HPAF-II, GC1436, GC1401, AGS, and GC1415 cancer cell lines. Furthermore, the antioxidant capacity of Fe3O4@Pectin NPswas determined by DPPH method which displayeda significant activity as per IC50 value. It is believed that the antioxidant effects play a significant role in the considerable anti-colorectal, pancreatic and gastric cancerseffects.

Proficient exclusion of pesticide using humic acid-modified magnetite nanoparticles from aqueous solution.

Extensive dispersal of the pesticides to shield the different types of vegetation from pests has increased the production but at the same it has resulted in an increase in environmental pollution. Consequently, it is necessary to eliminate these undesired pollutants from the environment. The current investigation offers the synthesis of humic acid-coated magnetite nanoparticles towards effective removal of the most common insecticide, imidacloprid, from aqueous solution using a batch adsorption method. These synthesized nanoparticles were characterized with the help of several analytical and spectroscopic techniques. To acquire the maximum conceivable adsorption, effects of different influencing parameters like pH of the solution, time of contact, concentration of pesticide solution, amount of adsorbent and temperature were also examined. Moreover, the kinetic studies were found to be in good agreement with a pseudo-second-order kinetic model supporting the occurrence of chemisorption phenomenon. Additionally, isotherm modeling proved that the adsorption process was in accordance with the Langmuir model of isotherm. Thermodynamic parameters depicted the endothermic and spontaneous behavior of the adsorption process. Desorption studies were also carried out to examine the reusability of these nano-adsorbents. These verdicts confirmed that the surface modified magnetite nanoparticles may be treated as proficient material for exclusion of imidacloprid from the aqueous solution.

Synergistic Integration and Pharmacomechanical Function of Enzyme-Magnetite Nanoparticle Swarms for Low-Dose Fast Thrombolysis.

Magnetic micro-/nanoparticles are extensively explored over the past decade as active diagnostic/therapeutic agents for minimally invasive medicine. However, sufficient function integration on these miniaturized bodies toward practical applications remains challenging. This work proposes a synergistic strategy via integrating particle functionalization and bioinspired swarming, demonstrated by recombinant tissue plasminogen activator modified magnetite nanoparticles (rtPA-Fe3 O4 NPs) for fast thrombolysis in vivo with low drug dosage. The synthesized rtPA-Fe3 O4 NPs exhibit superior magnetic performance, high biocompatibility, and thrombolytic enzyme activity. Benefiting from a customized magnetic operation system designed for animal experiments and preclinical development, these agglomeration-free NPs can assemble into micro-/milli-scale swarms capable of robust maneuver and reconfigurable transformation for on-demand tasks in complex biofluids. Specifically, the spinning mode of the swarm exerts focused fluid shear stresses while rubbing on the thrombus surface, constituting a mechanical force for clot breakdown. The synergy of the NPs' inherent enzymatic effect and swarming-triggered fluid forces enables amplified efficacy of thrombolysis in an in vivo occlusion model of rabbit carotid artery, using lower drug concentration than clinical dosage. Furthermore, swarming-enhanced ultrasound signals aid in imaging-guided treatment. Therefore, the pharmacomechanical NP swarms herein represent an injectable thrombolytic tool joining advantages of intravenous drug therapy and robotic intervention.

Pd Nanoparticles Decorated on Ionic Liquid Modified Magnetite Nanoparticles as a Recyclable and Active Nanocatalyst for Reduction of Nitro Compounds and Degradation of Organic Dyes

AbstractThe development of new technologies for the efficient degradation of toxic organic pollutants from water resources has received great attention. In this study, we described an effective method for the preparation of Pd nanoparticles (NPs) decorated on nitrogen rich ionic liquid (IL) modified magnetic nanoparticles and its application as the green and recoverable heterogeneous catalyst in the reductive degradation of organic dyes and reduction of nitro compounds. The Fe3O4/SiO2−IL−Pd nanocatalyst was characterized by several techniques namely, FT‐IR, FE‐SEM, EDX‐ elemental mapping, XRD, TEM, XPS, TGA and VSM. The Fe3O4/SiO2‐IL−Pd nanocatalyst was applied for the efficient reduction of structurally different nitroarenes, methyl orange (MO), methylene blue (MB) and methyl red (MR) in aqueous media using NaBH4 as reducing agent at room temperature. Using this catalyst nitroarenes were reduced to corresponding amines very efficiently and organic dyes reduced quantitatively under short reaction times. The catalyst can be recovered and recycled for at least ten runs without a notable decrease in the activity.

Modification of magnetite nanoparticles surface with multifunctional ionic liquids for coomassie brilliant blue R-250 dye removal from aqueous solutions

Multifunctional pyridinium ionic liquids with different alkyl chain lengths were used as coating agents to prepare surface modified magnetite nanoparticles (MNPs/MIL). The synthesized nanoparticles were well characterized using Fourier transformation of infrared spectroscopy (FTIR), X-Ray diffraction (XRD), dynamic light scattering (DLS), energy dispersive X-ray analysis (EDX) and transmission electron microscopy (TEM) techniques to indicate that MNPs were successfully coated with multifunctional pyridinium ionic liquid (MIL) to control their particle size and surface charge. The positive surface charges on the MNPs/MIL, as indicated from zeta potential measurements, recommend their application as adsorbents for coomassie brilliant blue-R250 anionic dye (CBB) from aqueous solutions. The results indicated the high adsorption capacities of the surface modified magnetite nanoparticles that reached to 702 and 691 mg/g for magnetite nanoparticles coated with tetradecyl multifunctional pyridinium ionic liquids (TMIL) and hexadecyl multifunctional pyridinium ionic liquids (HMIL), respectively comparing with bare magnetite that only reached 84 mg/g. The equilibrium isotherm and kinetic parameters were evaluated and analyzed using different models to indicate that pseudo-second-order kinetic and the Freundlich isotherm models were more suitable to describe the adsorption of CBB from aqueous solutions on Fe3O4/HMIL and Fe3O4/TMIL. The adsorption mechanism was suggested to be through electrostatic interaction, π–π interactions, and H-bonding.

Synthesis, Characterization, and Application of Magnetite Nanoparticles Coated with Hydrophobic Polyethyleneimine for Oil Spill Cleaning

Pollution with oil spills, a major contributor to water contamination, has a remarkable effect on the economy, biodiversity, and environment. To protect marine species and environment, efforts should be undertaken for developing efficient ways to remove oil spills. The current work discusses the oil spill removal using magnetite nanoparticles (MNPs) functionalized with hydrophobic polyethyleneimine (HPEA). In this respect, nonylphenol pentaethylenehexamine (NTEPA) and nonylphenol triethylenetetramine (NDETA) were prepared by a simple one-step method and used as capping agents in the synthesis of hydrophobically modified magnetite nanoparticles designated as NDETA/Fe3O4 (magnetite as a core and NDETA as a shell) and NTEPA/Fe3O4 (magnetite as a core and NTEPA as a shell). The prepared MNPs were characterized using FTIR, XRD, TEM, DLS, TGA, and DSA to determine their physical and chemical properties. Additionally, MNPs were applied as oil spill collectors with high efficiencies that reached 93% and 90% for NDETA/Fe3O4 and NTEPA/Fe3O4, respectively, at low magnetite to oil ratios.

Study of Isotherm and Kinetic Parameters for Efficient Adsorption of Methylene Blue Dye onto the Surface of Meldrum’s Acid Modified SPIONs

In present study, Meldrum’s acid modified magnetite nanoparticles (MA-Fe3O4) were synthesized for the removal of methylene blue by co-precipitation method. These coated nanoparticles were examined by TGA, FESEM, XRD, FTIR and UV-vis analysis. The FESEM results depicted that mean size of modified superparamagnetic iron oxide nanoparticles (SPIONs) was about 30 nm. Meldrum’s acid modified magnetic nanoparticles were found extremely effective in methylene blue dye adsorption from aqueous solution. The data obtained from isotherm study showed that adsorption process was consistent with Freundlich Model. Moreover, kinetic studies revealed that the adsorption of the dye on surface of coated magnetic nanoparticles followed pseudo-second order kinetics. Additionally, a comparative study has been made for the methylene blue dye removal efficiency by Meldrum’s acid modified magnetic nanoparticles with already reported adsorbents.

Chitosan modified Fe3O4 nanoparticles for hyperthermia application

Chitosan modified Magnetite nanoparticles (Fe3O4) were synthesized using solvo-thermal method. The structural characterization of the samples was performed by using x-ray diffraction (XRD) technique. The crystallite size of both bare and chitosan modified Nanoparticles were calculated from Scherrer’s formula and W-H plot which are found to be in the range of 20–30 nm. Transmission Electron Microscopy (TEM) analysis of the Chitosan (C) coated Fe3O4 reveals the emergence of almost spherical shape with agglomeration. The magnetization values obtained from VSM study at room temperature of both Fe3O4 and C-Fe3O4 are 71.871 emu/g and 60.275 emu/g respectively. The efficiency of Magnetic hyperthermic ability is also measured by calculating specific absorption rate (SAR) for both nanoparticles. At 187.09 Oe, Fe3O4 nanoparticles show maximum SAR of 173.6 W/g, while Chitosan modified Fe3O4 magnetic nanoparticles show a SAR of 161.16 W/g.

Magnetic composite sponges based on chitosan and whey protein modified magnetite nanoparticles for dye removal from water

Magnetic composite sponges based on chitosan and whey protein modified magnetite nanoparticles for dye removal from water

Introduction of PdCl2 supported on tartaric acid modified magnetite nanoparticles (Fe3O4@TA-Pd) as a novel catalytic system in Suzuki–Miyaura coupling reaction

In this paper, a new magnetically separable catalytic system based on Palladum (Pd) encapsulated with tartaric acid (TA) as a linker (Fe3O4@TA-Pd) is introduced in which TA as a hydroxy organic acid grafted onto the Fe3O4 nanoparticles (Fe3O4 NPs) readily forms complexes with Pd2+. To assess the catalytic capability of the prepared catalyst bearing Pd chelated with TA, it was exploited for achieving some biaryl compounds through Suzuki–Miyaura cross-coupling reaction of aryl halides with phenylboronic acid (PhB(OH)2). This catalyst was reused up to 7 runs with minimizing the change in its activity. Convenient preparation, easy separation and recoverability of this catalyst, facile and efficient transformation to biaryl products along with relatively excellent yields are of the superiorities of this catalyst.

Microwave assisted synthesis of oleic acid modified magnetite nanoparticles for benzene adsorption

Benzene is a carcinogenic, mutagenic and highly toxic nonpolar organic compound, its presence in water occurs as a result of leakage of underground pipes and improper effluent disposal. Adsorption techniques have proven to be efficient for benzene removal from water providing a low maintenance method with high removal efficiencies. Nanoparticles provide high surface areas for adsorption and magnetite particles are specifically advantageous owing to their magnetic characteristics. Magnetite surfaces require modification with hydrophobic compounds for the adsorption of nonpolar pollutants. Herein, magnetite nanoparticles (MNP) were modified with oleic acid to form a magnetite-oleic acid composite (MNP-OA) via microwave synthesis for the adsorption of benzene from simulated wastewater. Infrared analysis confirmed the interaction between magnetite and oleic acid and particle diameters were determined by XRD analysis as 19.7 nm and 17.1 nm for MNP and MNP-OA respectively. Magnetic measurements indicated that both materials were superparamagnetic with a decrease in saturation magnetization after modification due to the non-magnetic layer on the surface. Oleic acid modification improved the benzene uptake of magnetite nanoparticles by approximately 30 % while kinetic studies suggested that a concentration driving force controlled the adsorption process. The adsorbent was regenerated and was efficient for five adsorption-desorption cycles.

Hematopoietic Bone Marrow Cells of Rat after Intravenous Administration of Chitosan-Modified Magnetite Nanoparticles

Chitosan-modified magnetic nanoparticles are a promising basis for the creation of new diagnostic agents and therapeutic drugs. The cells of erythroid, granulocytic, monocytic, lymphocytic, and megakaryocytic lineages of bone marrow of mature rats were investigated for 120 days after single injection of 0.14 g per 1 kg body weight chitosan-modified magnetic nanoparticles (Fe3O4). Light microscopy was applied to describe the structure of hematopoietic cells and morphometric study was performed on Romanowsky—Giemsa stained smears to measure cells size (µm) and relative number (%). Comparison of the biological effects of nonmodified and modified magnetite nanoparticles on hematopoietic cells of bone marrow revealed the advantages of modification. Chitosan-modified magnetite nanoparticles did not affect the structure of hematopoietic cells in the rat bone marrow, and their injection produced a reversible increase in the relative number of monocytes, stab neutrophils and segmented neutrophils, as well as polychromatic and oxyphilic normoblasts.

Synthesis and characterization of magnetite nanoparticles by co-precipitation method coated with biocompatible compounds and evaluation of in-vitro cytotoxicity.

Recent advances in the use of magnetite nanoparticles for biomedical applications have led to special attention to these nanoparticles. The unique properties of magnetite nanoparticles such as superparamagnetism, low toxicity, and the ability to bond with biological molecules, are suitable for drug delivery, diagnostic methods and therapeutic approaches. The aim of this study was to synthesize magnetite nanoparticles with different biocompatible coatings and investigate their cytotoxicity. Magnetite nanoparticles were synthesized by co-precipitation method and the cytotoxicity of these nanoparticles was investigated with Hepatoma G2 cell using the MTT assay. Treated cells, did not showed any evident cell cycle arrest. The Fourier Transmission Infrared (FTIR) spectroscopy, X- ray powder Diffraction (XRD), Transmission Electron Microscopy (TEM) were evaluated. The results of XRD showed the coated magnetite nanoparticles were 10-12 nm and this size also achieved with TEM images. Synthesized magnetite nanoparticles with SiO2 and oleic acid coatings had lower cytotoxicity than other coatings.

Grafting β-Cyclodextrin/allyle glycidyl ether/thermosensitive containing polymer onto modified Fe3O4@SiO2 for adsorption of diazinon from aqueous solution

ABSTRACT In the present study, β-cyclodextrin/Allyl Glycidyl Ether (AGE)/thermo-sensitive polymer was grafted onto modified Fe3O4@SiO2 to be utilised as a possible adsorbent for diazinon removal from an aqueous solution. The modified magnetite Nano-Particles (NPs) were examined by using several techniques, including X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Elemental Analysis (EA), Vibrating Sample Magnetometry (VSM), and Thermo-Gravimetric Analysis (TGA). The effects of different parameters, such as pH, contact time, adsorption isotherm, reaction temperature, ultrasonic desorption, and reusability was evaluated. The results demonstrated that the best adsorption of diazinon on the modified magnetite nano-sorbent occurred at 20°C at the optimum pH of 6. The initial concentration and adsorbent dosage were 100 mg L−1 and 0.01 g, respectively. The kinetic study showed that the best time for the pesticide sorption was 2 min. Also, the Pseudo-Second-Order (PSO) model employed fitted the adsorption kinetics well, thus exhibiting high correlation coefficients. Diazinon adsorption capacity was found to be 34 mg g−1. The equilibrium data of diazinon modified by the magnetite nano-sorbent were suitably shown by Langmuir, Freundlich, Redlich-Peterson, and Temkin models. The data fitted well to Langmuir equation, thus indicating the monolayer adsorption. The reusability experiments revealed excellent removal capabilities of at least 10 times. The results demonstrated that the proposed method had the significant advantages of simplicity and efficiency for diazinon determination from real water samples.

Novel Bionanocompounds: Outer Membrane Protein A and Lacasse Co-Immobilized on Magnetite Nanoparticles for Produced Water Treatment.

The oil and gas industry generates large amounts of oil-derived effluents such as Heavy Crude Oil (HCO) in water (W) emulsions, which pose a significant remediation and recovery challenge due to their high stability and the presence of environmentally concerning compounds. Nanomaterials emerge as a suitable alternative for the recovery of such effluents, as they can separate them under mild conditions. Additionally, different biomolecules with bioremediation and interfacial capabilities have been explored to functionalize such nanomaterials to improve their performance even further. Here, we put forward the notion of combining these technologies for the simultaneous separation and treatment of O/W effluent emulsions by a novel co-immobilization approach where both OmpA (a biosurfactant) and Laccase (a remediation enzyme) were effectively immobilized on polyether amine (PEA)-modified magnetite nanoparticles (MNPs). The obtained bionanocompounds (i.e., MNP-PEA-OmpA, MNP-PEA-Laccase, and MNP-PEA-OmpA-Laccase) were successfully characterized via DLS, XRD, TEM, TGA, and FTIR. The demulsification of O/W emulsions was achieved by MNP-PEA-OmpA and MNP-PEA-OmpA-Laccase at 5000 ppm. This effect was further improved by applying an external magnetic field to approach HCO removal efficiencies of 81% and 88%, respectively. The degradation efficiencies with these two bionanocompounds reached levels of between 5% and 50% for the present compounds. Taken together, our results indicate that the developed nanoplatform holds significant promise for the efficient treatment of emulsified effluents from the oil and gas industry.