Production and Characterization of Green Biosorbent Based on Modified Corn Cob Decorated Magnetite Nanoparticles

In most developing countries, particularly in the countries of sub-Saharan Africa, corn cobs are considered as waste polluting the environment during the harvest period of this cereal. In order to valorize this agricultural waste, high-performance, inexpensive and low-energy consumption magnetic bioadsorbents were prepared from corn cobs. The chemically activated raw corn cob was magnetized by coating the surface with magnetite nanoparticles. The prepared biosorbents were characterized by FT-IR, XRD, FE-SEM associated with EDX, HR-TEM, TG analysis, BET surface area analysis and XPS. The maximum specific surface area of 35.22 m2/g was reached. An attempt to use of these magnetic biosorbents for the removal of heavy metal like Cr(VI) from aqueous solution was envisaged.

Application of Modified Silica Coated Magnetite Nanoparticles for Removal of Iodine from Water Samples

The adsorption of iodine onto silica coated magnetite nanoparticles(im-SCMNPs) that modified with imidazole was investigated for removal of high concentrations of iodine from wastewater. Modified silica magnetite nanoparticles showed high efficiency in removing iodine from wastewater samples. The optimum pH for iodine removal was 7.0-8.0. The adsorption capacity was evaluated using both the Langmuir and Freundlich adsorption isotherm models. The size of the produced magnetite nanoparticles was determined by X-ray diffraction analysis and scanning electron microscopy. Synthesized magnetite nanoparticles showed the high adsorption capacity and would be a good method to increase adsorption efficiency for the removal of iodine in a wastewater treatment process. The Langmuir adsorption capacity(qmax) was found to be 140.84 mg/g of the adsorbent.

Facile method to synthesize oleic acid-capped magnetite nanoparticles

We described a simple one-step process for the synthesis of oleic acid-capped magnetite nanoparticles using the dimethyl sulfoxide(DMSO) to oxidize the precursor Fe^(2+) at 140℃.By adjusting the alkalinity of the reaction system,magnetite nanoparticles with two sizes of 4 and 7 nm could be easily achieved.And the magnetite nanoparticles coated by oleate were well-monodispersed in organic solvent.

Green Synthesis of Magnetite Nanoparticles Using Aqueous Leaves Extracts of <i>Azadirachta indica</i>and Its Application for the Removal of As(V) from Water

Because of various disadvantages of chemical synthesis processes, these days people are attracting towards green synthesis processes as it is devoid of toxic by-products, cost-effective and eco-friendly. In this study, a simple green synthesis method is applied for the synthesis of magnetite (Fe3O4) nanoparticles (MNPs) by co-precipitation of FeCl3·6H2O and FeSO4·7H2O in the molar ratio of 2:1 using Azadirachta indica leaves extract under nitrogen environment. FTIR, XRD, SEM etc. were used to characterize the synthesized MNPs. Batch adsorption experiments were carried out to determine adsorption equilibrium of As(V) as a function of pH, adsorbent dose, contact time and different initial concentrations. Kinetics results were best described by pseudo-second order model with rate constant value 0.0052 g/(mg·min). The equilibrium adsorption isotherm was best fitted with Langmuir adsorption isotherm model. The maximum adsorption capacity was found to be 62.89 mg/g at pH 2. MNPs showed a high affinity for As(V) and avoids filtration for solid-liquid separation, thus it would be employed as a promising material for the removal of As(V) from water.

Comparative Study between Magnetite Nanoparticles and Magnetite/Silver as a Core/Shell Nanostructure

Magnetite nanoparticles (MNPs) and magnetite/silver nanoparticles (M/Ag NPs) were synthesized by chemical co-precipitation of Fe2+ and Fe3+. In case of M/Ag NPs, MNPs (core) were separately coated by silver metal (shell) in presence of glucose as a reducing agent. The particle size and morphology of the nanoparticles were characterized by dynamic light scattering (DLS) and scanning electron microscopy (SEM). Magnetic properties were investigated by vibrating sample magnetometry (VSM). The superparamagnetic natures of the nanoparticles were confirmed by the absence of the hysteresis loop. Coverage with silver produced a core-shell heterostructure which weakens magnetization of MNPs, inducing an inert character to the fnal nanostructure. The surface conjugation of MNPs with silver metal has been employed in order to improve the compatibility of magnetite nanoparticles to overcome their limitations in practical applications.

Hydrothermal Liquefaction of Water Hyacinth: Effect of Process Conditions and Magnetite Nanoparticles on Biocrude Yield and Composition

In this work, an efficient way of converting the water hyacinth to biocrude oil using magnetite nanoparticles (MNPs) as potential catalysts was demonstrated for the first time. MNPs were synthesised by co-precipitation and used in the hydrothermal liquefaction (HTL) of water hyacinth at different reaction conditions (temperature, reaction time, MNPs to biomass ratio and biomass to water ratio). The best reaction conditions were as follows: temperature— 320, reaction time—60 minutes, MNPs to biomass ratio – 0.2 g/g and biomass to water ratio – 0.06 g/g. HTL in presence of MNPs gave higher biocrude yields compared to HTL in absence of MNPs. The highest biocrude yield was 58.3 wt% compared to 52.3 wt% in absence of MNPs at similar reaction conditions. The composition of biocrude oil was analysed using GC-MS and elemental analysis. GC-MS results revealed that HTL in presence of MNPs led to an increase in the percentage area corresponding to hydrocarbons and a reduction in the percentage area corresponding to oxygenated compounds, nitrogenated compounds and sulphur compounds. Elemental analysis revealed an increase in the hydrogen and carbon content and a reduction in the nitrogen, oxygen and sulphur content of the biocrude when HTL was done in presence of MNPs compared to HTL in absence of MNPs. The nanoparticles were recovered from the biochar by sonication and magnetic separation and recycled. The recycled MNPs were still efficient as HTL catalysts and were recycled five times. The application of MNPs in the HTL of water hyacinth increases the yield of biocrude oil, improves the quality of biocrude through removal of hetero atoms, oxygen and sulphur compounds and is a potentially economical alternative to the traditional petroleum catalysts since MNPs are cheaper, widely available and can be easily recovered magnetically and recycled. This will potentially lead to an economical, environmentally friendly and sustainable way of producing biofuels from biomass.

Properties of Biogenic Magnetite Nanoparticles in the Radula of Chiton Acanthochiton rubrolineatus Lischke

The properties of biogenic magnetite（Fe 3 O 4 ）nanoparticles in chiton acanthochiton rubrolineatus lischke were characterized by selected electron diffractometry,high resolution transmission electron microscopy,Fourier transform infrared spectroscopy,M·ssbauer spectroscopy and magnetization measurements.Results showed that the magnetite nanoparticles presented crystalline appearance,exhibiting strong absorptions at 595,1 463,3 467 cm-1 and weak adsorptions at 1 697,1 113,1 048,848,445 cm-1 in FT-IR,two partially overlapping sextets in M·ssbauer spectrum,and the area ratio of the sextets was 1.08.Also,the particles exhibited ferromagnetic behavior,and had 82 A·m2/kg saturation magnetization,1.4·104 A/m coercive force and 4.0 A·m2/kg remnant magnetization,respectively.The investigation indicates that the biogenic magnetite nanoparticles mineralized in the chiton are impure in composition and non-stoichiometric.

Interfacial processes and mechanisms of synergistic degradation of dichlorobiphenyl by white rot fungi and magnetite nanoparticles

The rapid increase in the artificial syntheses of organic pollutants has raised widespread concern.However,the mechanisms by which fungi degrade these new organic pollutants in the environment and adapt to environmental stressors remain unclear.In this study,Phanerochaete chrysosporium,a model white rot fungus,was used to explore the interfacial processes and mechanisms for synergistic degradation of 4,4′-dichlorobiphenyl(PCB15)with magnetite nanoparticles.The results showed that after 3 and 5 days of cultivation with Phanerochaete chrysosporium alone,the rates for PCB15 degradation were 32%and 65%,respectively,indicating that the white rot fungus itself was able to degrade the organic pollutant.Moreover,the addition of magnetite nanoparticles significantly enhanced the degradation of PCB15 by Phanerochaete chrysosporium.After cocultivation for 3 and 5 days,the rates for PCB15 degradation increased to 42%and 84%,respectively.Synchrotron radiation-based Fourier transform infrared spectromicroscopy(SR-FTIR)showed that the magnetite particles were tightly adhered to the fungal hyphae and were unevenly distributed on the hyphal surfaces.Furthermore,cocultivation of the fungus and magnetite nanoparticles significantly enhanced the nanozymatic activity of magnetite.A linear regression model provided a significantly negative correlation(r=−0.96,p<0.001)between the nanozymatic activity of the magnetite and the concentration ratio of the PCB15,supporting the hypothesis that white rot fungi degraded the PCB15 by enhancing the nanozyme activity of magnetite.High-resolution X-ray photoelectron spectroscopy(XPS)revealed that the nanozymatic activity of magnetite was mainly governed by oxygen vacancies on the mineral surfaces rather than the iron valence.Together,these findings increase our understanding of the powerful capabilities of fungi in terms of stress resistance and adaptation to extreme environments and provide new insights into fungal-mediated degradation of organic pollutants for soil remediation in contaminated sites.

Growth of Magnetite Nanoparticles under Magnetic Fields

1 Introduction Over the past several years, the preparation and characterization ofnanoscale magnetic materials, especially one-dimensional (1D) nanostructure, have attracted much attention as the nanomaterials would allow investigating the fundamental aspects of magnetic-ordering phenomena in magnetic materials with reduced dimensions and could lead to new potential applications such as data storage technology[1-6].……

Interactions of ferro-nanoparticles(hematite and magnetite) with reservoir sandstone: implications for surface adsorption and interfacial tension reduction

There are a few studies on the use of ferro-nanofluids for enhanced oil recovery,despite their magnetic properties;hence,it is needed to study the adsorption of iron oxide(Fe2 O3 and Fe3 O4) nanoparticles(NPs) on rock surfaces.This is important as the colloidal transport of NPs through the reservoir is subject to particle adsorption on the rock surface.Molecular dynamics simulation was used to determine the interfacial energy(strength) and adsorption of Fe2 O3 and Fe3 O4 nanofluids infused in reservoir sandstones.Fourier transform infrared spectroscopy and X-ray photon spectroscopy(XPS) were used to monitor interaction of silicate species with Fe2 O3 and Fe3 O4.The spectral changes show the variation of dominating silicate anions in the solution.Also,the XPS peaks for Si,C and Fe at 190,285 and 700 eV,respectively,are less distinct in the spectra of sandstone aged in the Fe3 O4 nanofluid,suggesting the intense adsorption of the Fe3 O4 with the crude oil.The measured IFT for brine/oil,Fe2 O3/oil and Fe3 O4/oil are 40,36.17 and 31 mN/m,respectively.Fe3 O4 infused with reservoir sandstone exhibits a higher silicate sorption capacity than Fe2 O3,due to their larger number of active surface sites and saturation magnetization,which accounts for the effectiveness of Fe3 O4 in reducing IFT.

Inductive heat property of Fe_3O_4 nanoparticles in AC magnetic field for local hyperthermia

Magnetite (Fe3O4) nanoparticles with different magnetic properties were prepared by coprecipitation of Fe3+ and Fe2+ with aqueous NaOH solution. The inductive heat properties of Fe3O4 nanoparticles in an alternating current (AC) magnetic field were investigated for local hyperthermia. The maximum saturation magnetization Ms of Fe3O4 nanoparticles is 65.53 emu·g-1 under the optimum conditions of Fe3+: Fe2+ molar ratio at 1.8:1. The Ms of Fe3O4 nanoparticles decreased as the Fe3+/Fe2+ molar ratio increased. But the coercivity Hc increases with the increasing of Fe3+/Fe2+ molar ratio. Exposed in the AC magnetic field for 29 min, the temperatures of physiological saline suspension containing Fe3O4 nanoparticles were 42-97.5 ℃. The inductive heat property of Fe3O4 nanoparticles in AC magnetic field decreases as Hc increases, but increases with the increasing of Ms. The Fe3O4 nanoparticles would be useful as good thermoseeds for localized hyperthermia treatment of cancers.

Effect of Fe_(3)O_(4) nanoparticles on magnetic xerogel composites for enhanced removal of fluoride and arsenic from aqueous solution

Fe_(3)O_(4)magnetic xerogel composites were prepared by polycondensation of resorcinol(R)-formaldehyde reaction via a sol-gel process in an aqueous solution through varying the molar ratio of Fe_(3)O_(4)nanoparticles(MNPs),catalyst(C),and water(W)content.MNPs were obtained by co-precipitation(MC),oxidation of iron salts(MO),or solvothermal synthesis(MS).Both MNPs and magnetic xerogels were examined regarding the performance of arsenic and fluoride removal in a batch system.The MC-based MNPs had higher adsorption capacities for both fluoride(202.9 mg/g)and arsenic(3.2 mg/g)than other MNPs in optimum conditions.The X-ray diffraction,Fourier transform infrared spectroscopy,and energy-dispersive X-ray spectroscopy confirmed that Fe was composed into the polymeric matrix of magnetic xerogels that contained 0.59%-4.42%of Fe with a molar ratio of MNPs(M)to R between 0.01 and 0.10.With low R/C and optimum M/R ratios,an increase in the surface area of magnetic xerogels affected the fluoride and arsenic adsorption capacities.The magnetic xerogel composites with the MC-based MNPs prepared at a fixed R/C ratio(100)and at different R/W(0.05-0.06)and M/R(0.07-0.10)ratios had a high arsenic removal efficiency of 100%at an As(V)concentration of 0.1 mg/L and pH of 3.0.The maximum adsorption capacities of magnetic xerogels were approximately five times higher than those of the xerogels without MNP composites.Therefore,Fe_(3)O_(4)nanoparticles enhanced the adsorption of arsenate and fluoride.The variations of alkaline catalyst and water content significantly affected the resulting properties of textural and surface chemistry of magnetic xerogel composites.

Synthesis and characterization of Fe_3O_4@SiO_2 magnetic composite nanoparticles by a one-pot process

Fe3O4@SiO2 core–shell composite nanoparticles were successfully prepared by a one-pot process. Tetraethyl-orthosilicate was used as a surfactant to synthesize Fe3O4@SiO2 core–shell structures from prepared Fe3O4 nanoparticles. The properties of the Fe3O4 and Fe3O4@SiO2 composite nanoparticles were studied by X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, and Fourier transform infrared spectroscopy. The prepared Fe3O4 particles were approximately 12 nm in size, and the thickness of the SiO2 coating was approximately 4 nm. The magnetic properties were studied by vibrating sample magnetometry. The results show that the maximum saturation magnetization of the Fe3O4@SiO2 powder（34.85 A·m^2·kg^–1） was markedly lower than that of the Fe3O4 powder（79.55 A·m^2·kg^–1）, which demonstrates that Fe3O4 was successfully wrapped by SiO2. The Fe3O4@SiO2 composite nanoparticles have broad prospects in biomedical applications; thus, our next study will apply them in magnetic resonance imaging.

Surface modification of Fe_3O_4 nanoparticles and their magnetic properties

Fe3O4 magnetic nanoparticles were synthesized by the hydrothermal method, and the influences of the surfactant sodium bis（2-ethylhexyl） sulfosuecinate （AOT） on the particles were investigated. The structure, morphology, and magnetic properties of the products were characterized by X-ray powder diffraction （XRD）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FT-IR）, and vibrating sample magnetometer （VSM）. It is confirmed that the as-prepared nanoparticles have been modified by using the surfactant during the synthesis process. The amount of the surfactant has an effect on the size, the dispersal, and the magnetic properties of the particles. Besides, the mechanisms of the influences were also discussed.

Investigation of Influence of Magnetic Nanoparticles on the Quality-Factor of the Oscillatory Circuit

In this study, author investigated the spectral response of EM （electromagnetic） energy absorption in a colloidal system of Fe3O4 nanoparticles with an average size of 9.50 nm immersed in a 2% aqueous solution of SDS （sodium dodeci[ sulfate）. The temperature of the nanoparticles and the SDS solution was evaluated by a novel method based on measuring the Q-factor （quality-factor） of a resonant circuit. The Q-factor of the investigated system as a function of the frequency of the EM field was obtained. The nanoparticles-SDS liquid system exhibited a resonance-like behavior of the absorption, where the resonance frequency was about 170 MHz, and the absorption rise up to the resonance frequency was rather slow. The observed absorption of EM energy was accompanied by a small temperature increasing of the system. Measurements of the ESR （electron spin resonance） spectrum of the Fe3O4 nanoparticles have presented a slightly asymmetric singlet with the proportionality factor g = 2 and a line-width of the magnetic field strength △H = 0.1 mT. It was shown that the observed absorption spectrum corresponds to paramagnetic behavior of the investigated nanoparticles.

Fabrication and Characterisation of Novel Natural Lycopodium clavatum Sporopollenin Microcapsules Loaded In-Situ with Nano-Magnetic Humic Acid-Metal Complexes

Sporopollenin exines microcapsules, derived from the naturally occurring spores of Lycopodium clavatum, have been loaded in-situ with humic acid sodium salt-Zinc (HA-Zn) complex. The chemical treatment method utilised to prepare the sporopollenin microcapsules from raw spores was discussed and the resulted sporopollenin microcapsules were characterised using SEM, TGA and FTIR. Metal complexes of the sodium salt of humic acid and zinc ion were prepared using different protocols and in-situ loaded into the pre-treated sporopollenin microcapsules. The resulted complex was characterised before and after the encapsulation process using FTIR, TGA and XRD techniques. The morphology of the empty and loaded sporopollenin was not altered. Infrared spectroscopy revealed an increase in the absorption for COO– vibrations at 1583 and 1384 cm–1 in the FTIR spectra of HA-Zn complex compared to that of the original sodium salt of humic acid, indicative of bonding of the metal ions in hydrated form to the carboxyl or phenolic hydroxyl groups or both of the sodium humate molecules. TGA results of the HA-Zn complex loaded sporopollenin showed that around %15 of residual HA-Zn was successfully encapsulated indicative of the efficiency of the protocol used. We showed also that biodegradable magnetite nanoparticles can be surface modified with HA and encapsulated into sporopollenin. The resulted biosorbents microcapsules can be used for enhanced magnetic removal of either heavy metals or HA from different aqueous media.

Synthesis and characterization of water-soluble magnetite nanocrystals via one-step sol-gel pathway

Water-soluble magnetite nanocrystals have been prepared by one-step non-alkoxide sol-gel method.The magnetic properties of magnetite nanocrystals obtained are size dependent.The experimental results also reveal that 2-pyrrolidone not only serves as solvent,but also involves surface coordination which renders the magnetite nanoparticles water-soluble and colloidal solution stable.Although the current synthetic approach is a small modification to the non-alkoxide sol-gel method,it allows us to directly obtain high-quality water-soluble magnetic nanocrystals.In addition,we realize that this method could be easily extended to preparation of many other transition and main group metal oxide water-soluble nanocrystals only from simple metal ion salts.

Fabrication of a Magnetite Nanoparticle-loaded Polymeric Nanoplatform for Magnetically Guided Drug Delivery

We developed a magnetite nanoparticle-loaded polymeric nanoplatform for magnetically guided 10- hydroxycamptothecin（HCPT） delivery. The nanoplatform was fabricated by simultaneously incorporating magnetite nanoparticles（NPs） and HCPT into the polymer micelle self-assembled from methoxy polyethylene glycolpoly（D,L-lactide-co-glycolide）（MPEG-PLGA） copolymer. Successful loading of HCPT into the nanoplatform was confirmed by Fourier transform infrared（FTIR） spectroscopy. Subsequently, we examined the in vitro antitumor efficacy of free HCPT and nanoplatform against three different cancer cell lines HeLa, A549 and HepG2. Flow cytometric analysis was condkt ,ucted to reveal the cell apoptosis caused by free HCPT and nanoplatform. Finally, the magnetic targeting property of the nanoplatform was evaluated by a self-designed in vitro experiment.

SYNTHESIS AND CHARACTERIZATION OF SURFACE-HYPERBRANCHED MAGNETITE NANOPARTICLE FOR BOVINE SERUM ALBUMIN IMMOBILIZATION

A hyperbranched polyamidoamine polymer was synthesized on the surface of magnetite nanoparticles to enhance bovine serum albumin (BSA) immobilization efficiency. The amount of immobilized bovine serum albumin (BSA) on the surface-hyperbranched magnetite nanoparticle was up to 2.5 times as much as that of magnetite nanoparticle modified with only amino silane.