Magnetic Iron Oxide Particles Research Articles

Design and characterisation of activated magnetic zeolite 4A from naturally occurring kaolin clay of Cameroonian origin for optimised dye removal by Fenton-like degradation

ABSTRACT The transformation of local clay material of Cameroonian origin into magnetic zeolite (Fe@Zeo-4A) for the degradation of acid-blue 90 in solution was investigate herein. The insertion of magnetic iron oxide particles into the zeolitic framework of Zeo-4A was achieved via hydrothermal synthesis. FT-IR spectroscopy, XRD and SEM confirmed the transformation of the clay into zeolite while EDX analysis and elemental mappings confirmed the presence of iron in the magnetic zeolite. Fe@Zeo-4A was strongly attracted to an external magnetic field. N2 adsorption-desorption studies revealed a considerable decrease in specific surface area and pore volume from the zeolite to the magnetic zeolite, suggesting the occupation of the pores of the zeolite by magnetite. The central composite design of the response surface methodology was used as optimisation approach for four parameters affecting the efficiency of degradation: solution pH, H2O2 concentration, initial dye concentration and time of stirring. ANOVA results revealed good correlation between the experimental and predicted results as well as the suitability of the linear regression model for describing the dye degradation process. An adjusted correlation coefficient of 85.17% was obtained for the dye degradation model. An optimal degradation percentage of 95.2% was obtained experimentally under optimal conditions of 7.6 for pH, 20 mg/L for dye concentration, 15.0 mol/L for [H2O2] and 15 min for time, in close agreement with a theoretical response of 96.6% predicted by the model. The magnetic zeolite was found to exhibit good stability over a wide pH range and lost only about 18% of its catalytic efficiency after five cycles of degradation experiments. Therefore, the novel magnetic zeolite-based material is an efficient Fenton catalyst for treating dye-contaminated wastewater.

Within-city spatial variations in PM2.5 magnetite nanoparticles and brain cancer incidence in Toronto and Montreal, Canada.

Magnetite nanoparticles are small, strongly magnetic iron oxide particles which are produced during high-temperature combustion and friction processes and form part of the outdoor air pollution mixture. These particles can translocate to the brain and have been found in human brain tissue. In this study, we estimated associations between within-city spatial variations in concentrations of magnetite nanoparticles in outdoor fine particulate matter (PM2.5) and brain cancer incidence. We performed a cohort study of 1.29 million participants in four cycles of the Canadian Census Health and Environment Cohort in Montreal and Toronto, Canada who were followed for malignant brain tumour (glioma) incidence. As a proxy for magnetite nanoparticle content, we measured the susceptibility of anhysteretic remanent magnetization (χARM) in PM2.5 samples (N = 124 in Montreal, N = 110 in Toronto), and values were assigned to residential locations. Stratified Cox proportional hazards models were used to estimate hazard ratios (per IQR change in volume-normalized χARM). ARM was not associated with brain tumour incidence (HR = 0.998, 95% CI 0.988, 1.009) after adjusting for relevant potential confounders. Although we found no evidence of an important relationship between within-city spatial variations in airborne magnetite nanoparticles and brain tumour incidence, further research is needed to evaluate this understudied exposure, and other measures of exposure to magnetite nanoparticles should be considered.

Recovery and reuse of magnetic silica-coated iron oxide particles for eco-friendly chemical mechanical planarization

Chemical mechanical planarization (CMP), a crucial process in semiconductor manufacturing, raises environmental concerns due to increased waste generation, prompting questions about its long-term sustainability. To address this issue, we explore an innovative approach to the waste management and recycling process by introducing magnetite (Fe3O4) particles coated with SiO2 layers, aimed at enhancing the CMP recycling efficiency. These core-shell particles exhibit controlled shell thickness, and modified surface charges, as confirmed by various analytical techniques. Our results reveal that slurries containing Fe3O4@SiO2 particles significantly improve W removal rates and surface smoothness compared to conventional slurries, attributed to the optimal mechanical properties. Moreover, the magnetite core facilitates the magnetic separation and recovery of used particles from spent slurries, offering a cost-effective and environmentally friendly solution. The recycling efficacy of these particles is demonstrated through multiple CMP cycles, showing consistent removal rates and surface quality, highlighting the potential of magnetic separation in sustainable CMP.

Exploring gunshot residue detection in fingerprints by functionalized particle-coupled matrix-assisted laser desorption/ionization mass spectrometry.

In firearm forensic investigations, detecting gunshot residue (GSR) is crucial for linking firearms to suspects and determining firing distance for forensic reconstruction. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS) is emerging as a versatile and promising technological platform for fingerprint analysis. The capability of functionalized particles as an advanced dusting powder for visualizing latent fingerprints is widely recognized. This study aims to investigate the feasibility of employing functionalized magnetic fingerprint dusting powders for distinguishing regular and GSR fingerprints using MALDI-ToF-MS, thereby enhancing forensic evidentiary support. In this study, silica and carbon coated magnetic iron oxide particles were surface functionalized with phenyltriethoxy orthosilicate (PTEOS) or 3-aminopropyl triethoxysilane (APTES) to create hydrophobic and hydrophilic particles, respectively. Donor shooters' fingerprints, both GSR-containing and regular, were analyzed using these functionalized particles coupled with MALDI-ToF-MS. The results demonstrated effective fingerprint visualization and conclusive discrimination between GSR-containing and regular fingerprints through orthogonal partial least squares discriminant analysis. This technique provides enhanced sensitivity, speed, and adaptability compared to conventional methods, making it a promising choice for initial detection of GSR in latent fingerprints. Moreover, when subjected to thorough analysis using advanced instruments, it has the potential to significantly strengthen the probative value of fingerprint evidence in forensic investigations.

The Effect of Mo Addition on Iron Oxide Magnetic Particles Synthesis by Silica Gel Method

The Effect of Mo Addition on Iron Oxide Magnetic Particles Synthesis by Silica Gel Method

Microwave-Assisted Solvothermal Synthesis of Nanocrystallite-Derived Magnetite Spheres.

The synthesis of magnetic particles triggers the interest of many scientists due to their relevant properties and wide range of applications in the catalysis, nanomedicine, biosensing and magnetic separation fields. A fast synthesis of iron oxide magnetic particles using an eco-friendly and facile microwave-assisted solvothermal method is presented in this study. Submicron Fe3O4 spheres were prepared using FeCl3 as an iron source, ethylene glycol as a solvent and reductor and sodium acetate as a precipitating and nucleating agent. The influence of the presence of polyethylene glycol as an additional reductor and heat absorbent was also evaluated. We reduce the synthesis time to 1 min by increasing the reaction temperature using the microwave-assisted solvothermal synthesis method under pressure or by adding PEG at lower temperatures. The obtained magnetite spheres are 200–300 nm in size and are composed of 10–30 nm sized crystallites. The synthesized particles were investigated using the XRD, TGA, pulsed-field magnetometry, Raman and FTIR methods. It was determined that adding PEG results in spheres with mixed magnetite and maghemite compositions, and the synthesis time increases the size of the crystallites. The presented results provide insights into the microwave-assisted solvothermal synthesis method and ensure a fast route to obtaining spherical magnetic particles composed of different sized nanocrystallites.

Arsenite removal from drinking water by bark-based magnetic iron oxide particle (BMIOP): a column study.

The removal of arsenite [As(III)] from drinking water was investigated in a column at flow rates of 2.0 and 5.0mL/min (up-flow direction) using bark-based magnetic iron oxide particles (BMIOP) prepared by coating (Fe(NO3)3.9H2O) over Tamarindus Indica bark. The BMIOP was compared with regenerated BMIOP, commercial activated carbon, commercial activated alumina (Al2O3). At 2.0mL/min, empty bed contact time (EBCT), breakthrough time (BT), the volume of treated water and breakthrough capacity (BC) on fresh BMIOP were found to be 6.8min, 33.15h, 4.380 L and 0.742mg/g, respectively, and at 5.0mL/min, were found to be 4.1min, 13h, 3.675 L and 0.453mg/g respectively. EBCT, BT and BC were increased by 65.85%, 155% and 63.79%, respectively, as the flow rate was reduced from 5.0 to 2.0mL/min. After regeneration of BMIOP, EBCT, BT, saturated time, BC and saturation capacity (SC) were reduced by 21.95%, 15.38%, 55.15%, 16.78% and 29.71%, respectively. The BC of fresh BMIOP was increased by factors 4.15, 3.60 and 1.20 and SC by factors 9.51, 7.88 and 1.42 compared to commercial activated carbon, commercial activated Al2O3 and regenerated BMIOP, respectively. Logit model could be used for the design of the adsorption column. Thomas model and artificial neural network (ANN) were applied to predict the characteristic column parameters useful for process design. Quality of treated water meets BIS requirements. Toxicity Characteristic Leaching Procedure (TCLP) and semi-dynamic tests show that the exhausted BMIOP is safe for disposal in a secure landfill; hence, BMIOP has been proved to separate As(III) from water.

Magnetically responsive low-cost adsorbents for aniline removal

Aniline (benzenamine) is a very important substance used in industry even though it is classified as very toxic. The need for a practical solution to remove it from the environment is still a current topic. Aniline adsorption from water solution was evaluated using low-cost, magnetically responsive adsorbents of different type (plant derived materials, microbial and algae biomass, carbon-based and inorganic materials). Magnetic modification, based on the deposition of magnetic iron oxide particles on material surface, enabled rapid adsorbent separation from the analyzed solutions. Carbon-based materials including activated charcoal and biochars exhibited the best adsorption properties. Biochar pyrolysis temperature substantially influenced its affinity for aniline adsorption. Maximum adsorption capacity for magnetically modified spruce biochar pyrolyzed at 1200 °C was 75.7 mg/g. • Aniline (benzenamine) is a very important emerging contaminant. • Aniline adsorption was evaluated using low-cost, magnetically responsive adsorbents. • Carbon-based materials including biochars exhibited the best adsorption properties. • Biochar pyrolysis temperature substantially influenced its affinity for aniline adsorption. Statement of novelty: Large amount of (bio)materials was magnetically modified and tested as possible adsorbents for aniline removal. Magnetic modification enabled rapid adsorbent separation from the analyzed solutions. Magnetic activated carbon, as well as low-cost magnetic biochar, exhibited the best adsorption properties and can be used for efficient aniline removal. Magnetic biochars represent valuable and efficient adsorbents for environmental remediation.

Iron-Oxide Magnetic Particles with Specific Ligand for Proteases Purification: Synthesis and Characterization

Iron-Oxide Magnetic Particles with Specific Ligand for Proteases Purification: Synthesis and Characterization

Study of Endogenous Paramagnetic Centers in Biological Systems from Different Areas

Plant leaves (Eldar pine (Pinus eldarica M.), fig (Ficus carica L.), and olive (Olea europaea L.)), collected in territories with different ecological conditions, of the Absheron Peninsula (Azerbaijan Republic) were studied by electron paramagnetic resonance spectroscopy (EPR). The generation of nanophase iron oxide magnetic particles in biological systems under the influence of stress factors was revealed. It was found that the process of biomineralization plays a role in the formation of biogenic iron oxide magnetic nanoparticles in plants and the generation of magnetite crystals in biological tissues, and stress factors have a stimulating effect on this phenomenon.

Efficient exclusion of uranyl ion from aqueous medium by a novel magnetic bio adsorbent (Phyllanthus emblica bark)

The exclusion process of uranyl ion in an aqueous medium is carried out with an adsorption method. The existence of uranyl ion in the environment is a matter of concern due to its toxicity. The biotic factor has been affected badly with the presence of uranyl ion above a permissible limit. In the present study, iron oxide magnetic particles (Fe3O4) were successfully fused with tree bark of Phyllanthus emblica by chemical precipitation, which was characterized by XRD, FTIR, and SEM-EDS study. Moreover, Phyllanthus emblica bark is extremely rich in iron and magnetic adsorbent does not produce any secondary pollutant as compared to other adsorbents. It is a novel as well as green approach towards environment. The amount of the adsorbent (0.3 gm/50 ml) could remove 85.6% of U(VI) in 40 min from a metal ion solution concentration 25 mg/L at room temperature (303 K). The equilibrium adsorption is reported at pH = 7. The adsorption isotherm is defined by Langmuir (r2 = 0.963), while the kinetic interest profile is considered by the kinetics of pseudo second-order (r2 = 0.9988). Estimated thermodynamic parameters are fit for present investigation.

Impact of the charge transfer process on the Fe2+/Fe3+distribution at Fe3O4 magnetic surface induced by deposited Pd clusters

Magnetic iron oxide particles decorated with transition-metal nanoparticles have become increasingly attractive in catalysis regarding the environment modifications, such as an additive ligand or carrier, which could significantly influence their performances. In this work, we used the Density Functional Theory (DFT) in the gradient approximation to study the interaction between the metal and its support for palladium and palladium oxide clusters on the surface of Fe3O4(001)magnetite. We report a dynamic process promoted by the palladium deposition with charge transfer from the metal host. An increase in the Fe2+/Fe3+ ratio at the topmost surface of the support was determined. The reduction of surface Fe3+ ions with electrons located at the interface has been proposed. Surprisingly, this slight increase in the surface density in Fe2+ ions was not observed in palladium oxide when the charge transfer from the support was significantly enhanced. Finally, the impact of the charge transfer process between the surface and the adsorbed species on palladium in terms of structure stability was discussed.

Magnetorheological Fluids with Surface-Modified Iron Oxide Magnetic Particles with Controlled Size and Shape.

This study is focused on surface-modified Fe3O4@SiO2 particles with precisely controlled sizes and shapes applied in magnetorheological (MR) fluids. After the preparation of the monodisperse spindle-shaped and cubic Fe3O4@SiO2 particles, surface modification with dodecyltrimethoxysilane (DTM) was carried out via a silane coupling reaction to increase the dispersion stability of the particles. Afterward, MR fluids were prepared by mixing the DTM-modified Fe3O4@SiO2 particles with silicon oil. Transmission electron microscopy observations demonstrated that spindle-shaped Fe3O4@SiO2 particles could form a more stable chain-like structure than cubic Fe3O4@SiO2 particles upon application of an external magnetic field. The rheological measurements of MR fluids also indicated that the surface modification with DTM, the introduction of anisotropic shapes, and the increase in the particle size all played positive roles in the improvement in MR properties.

One-pot strategy for obtaining magnetic PMMA particles through ATRP using Fe(CO)5 as co-initiator

The first aim of this study was to develop an ATRP process for methyl methacrylate (MMA) polymerization using Fe(CO)5 as co-initiator. The kinetics analysis of the reaction in solution confirmed the controlled characteristic of the polymerization process. The process displays a slow initiation step and presents bimolecular termination reactions at higher molecular weights, confirmed by NMR analysis. Also, these observations are sustained by GPC, FT-IR, and XPS analyses, explaining the rather unusual dispersity values (1.4) for an ATRP reaction. The use of formic acid, which shifts the equilibrium towards Fe2+ species affording a quasi-controlled controlled polymerization process, is a key element in achieving control over the reaction. The Fe2+/Fe3+ ratio at the end of the reaction, determined by XPS analysis, suggests the possibility to generate magnetic iron oxide particles. Therefore, the synthesis strategy was adapted for use in the suspension polymerization process of MMA which permitted the production of magnetic PMMA particles through a facile one-pot approach, using only an ammonia treatment stage. The obtained PMMA particles, characterized by SEM, XPS, TEM, TGA, and XRD analyses, have porous characteristics and magnetic properties which makes them good candidates as catalyst supports, separation processes, or biomedical applications.

Precipitation of Magnetic Iron Oxide Induced by Sporosarcina pasteurii Cells.

Sporosarcina pasteurii (S. pasteurii) is bacterium notable for its highly efficient urea degradation ability. Due to its high urease activity, S. pasteurii has been successfully utilized in applications including solidifying soil or sand, termed “bio-concrete”. In addition to calcium carbonate precipitation, urease isolated from the jack bean plant was recently demonstrated to induce the formation of magnetic iron oxide particles from soluble ferrous ion in a designed reaction. However, it remained unknown if a similar magnetic material could be formed using whole cells with high urease activity under biocompatible conditions. Here, we demonstrated that magnetic iron oxide with a highly ordered structure could be formed on the surface of S. pasteurii cells with a theoretical product of 1.17 mg in a 2-mL reaction. Moreover, the cells surrounded by the precipitated magnetic iron oxide maintained their viability. Due to the simple cultivation of S. pasteurii, the process developed in this study could be useful for the green synthesis of magnetic iron oxide, basic research on the mechanism of magnetic microbial-induced precipitation (MIP), and related engineering applications.

Preparation and characterization of PAni(CA)/Magnetic iron oxide hybrids and evaluation in adsorption/photodegradation of blue methylene dye

In this work hybrids of citric acid doped polyaniline and magnetic iron oxide (MOM) were prepared by in situ chemical polymerization and evaluated in blue methylene dye (MB) adsorption/photodegradation in aqueous medium. The samples were characterized by vibration absorption spectroscopy in the infrared region, X-ray diffraction, thermogravimetric analysis, transmission electron microscopy, Mössbauer spectroscopy, vibration sample magnetometry and electrical conductivity measurements using the four-point method. The characterization results showed that magnetic iron oxide consists of magnetite and maghemite phases with superparamagnetic behavior at room temperature. The hybrids materials present magnetic iron oxide particles dispersed in the polymer phase and electrical conductivity of the order of 10−2S cm−1 and showed adsorbent properties. The adsorption process prevails in relation to the photodegradation, but in the hybrids with higher content of MOM an increase in MB removal was observed under UV irradiation, with reduction of 99% of the dye concentration, indicating synergism between the MOM -polymer phases in the photocatalytic action. These results are related to the hybrids morphology.

Magnetic solid phase extraction of silver-based nanoparticles in aqueous samples: Influence of particle composition and matrix effects on its application to environmental samples and species-selective elution and determination of silver sulphide nanoparticles with sp-ICP-MS

Silver-based nanoparticles (Ag-b-NPs) are currently a cause for concern because they are being produced in increasing quantities for use in industrial goods and consumer products. This goes hand in hand with their release to the environment and the resultant risks for the entire ecosystem. Therefore, it is essential that these materials are monitored. A promising technique that overcomes a number of shortcomings in handling environmental samples is magnetic solid phase extraction (MSPE) of Ag-b-NPs, which is applied in this study. It has been possible to extract different kinds of Ag-b-NPs at environmentally relevant concentrations in the low ng L−1 range using iron oxide magnetic particles (IOMPs) of different size and shape with efficiencies in the range from 80 to 100%. Furthermore, environmentally relevant inorganic ions and TiO2 particles exhibited no major effect on the extraction efficiency. However, natural organic matter (NOM) exhibited a significant influence from 1 mg L−1 resulting in a 50% drop in extraction efficiency. This effect could be overcome by adding 10 mM Ca2+ or increasing the iron oxide magnetic particle (IOMP) concentration to 500 mg L−1. Applying the presented procedure, Ag-b-NPs added to a river water sample at βAg = 50 ng L−1 were successfully extracted. We also investigated the coextraction of Ag+, demonstrating that NOM could eliminate coextraction. The subsequent species-selective elution of Ag2S-NPs after MSPE, was carried out based on ethylene diamine tetraacetate (EDTA) as eluent in different matrices. A desorption efficiency of 76 ± 6% could be achieved while preserving the Ag2S-NPs' size. By contrast, core Ag-NPs and AgCl-NPs are dissolved if the presented method is followed.

Structural and Morphological Properties of Undoped and Manganese Doped Hematite Nanoparticles Prepared by Ball Milling Method

Hematite nanoparticles of undoped and manganese doped were synthesized from natural sand of Logas District Kuansing Regency Riau Province by ball milling method. Structural and morphological properties of these compounds were studied using X-Ray Diffractometer (XRD) and Scanning electron microscope (SEM) respectively. Crystalline structure, lattice parameters, morphologies of the synthesized compounds were studied and the results are discussed. X-ray diffraction (XRD) confirmed the presence of a hematite (α-Fe2O3) phase. Average crystallite size based on flections (1 0 4) for undoped and manganese doped magnetic iron oxide particles are 39.2 nm and 38.2 respectively. The intensity of (1 0 4) reflection is stronger for magnetic iron oxide synthesized for 60 hours than that of 2 step (60+60) hours ball milling. This indicates the product grown along (1 0 4) direction. The average crystallite size decreases when magnetic iron oxide is doped with 10% Mn as confirmed by SEM images.

The Effect of Synthesis Procedure on Hydrogen Peroxidase-Like Catalytic Activity of Iron Oxide Magnetic Particles

A comparative study was carried out using magnetic nanoparticles (MNPs) for the fabrication of non-enzymatic sensors for the continuous and rapid detection and monitoring of H2O2. Various MNPs, differing in terms of their synthesis procedure and modification, were synthesized and characterized by different techniques. The electrochemical catalytic activity of the synthesized MNPs toward the reduction in H2O2 was investigated by cyclic voltammetry. The naked MNPs showed the highest catalytic activity among all the synthesized MNPs. The biosensor based on the naked MNPs was then applied in the determination of H2O2 using chronoamperometry. The parameters such as the applied cathodic potential and the amount of MNPs on the developed biosensor were optimized. Moreover, the analytical figures of merit, including reproducibility (RSD = 6.14%), sensitivity (m = 0.0676 µA µM−1), limit of detection (LOD) = 27.02 µmol L−1, and limit of quantification (LOQ) = 89.26 µmol L−1 of the developed biosensor indicate satisfactory analysis. Finally, MNPs were successfully utilized for the determination of H2O2 in milk.

Morphology and Structural Properties of Undoped and Cobalt Doped Magnetic Iron Oxide Particles for Improving the Environmental Quality

Doping of metal ions in magnetic iron oxide particles can improve its performance and lead to its new technological and industrial applications. Magnetic iron oxide particles of undoped and cobalt doped were synthesized from natural sand of Logas District Kuansing Regency by ball milling method. The structural properties and the morphology of the magnetic iron oxide F e2O3 particles were analyzed using X-Ray Diffractometer (XRD) and scanning electron microscope (SEM). The X-ray diffractometric study showed that X-ray diffraction (XRD) peaks shift to slightly higher angles as compared to those of undoped magnetic iron oxide particles. This shift is due to relatively smaller ionic radius of cobalt as compared to those for iron. Moreover, peaks corresponding to cobalt oxide or metal cobalt could not be observed in the diffraction pattern. Some other diffraction peaks from other crystalline forms such as silicon (Si) and titanium (Ti) were observed.