Crystalline Magnetite Research Articles

Preparation, characterization and application of polymeric ultra-permeable biodegradable ferromagnetic nanocomposite adsorbent for removal of Cr(VI) from synthetic wastewater: kinetics, isotherms and thermodynamics

Hexavalent chromium (Cr(VI)) contamination in drinking water due to industrial activities is a growing worldwide concern. Cr(VI) concentrations exceeding a few parts per billion (ppb) can cause serious health problems such as asthma, blood cancer, kidney-related diseases, liver and spleen damage, as well as neurological system, immunological deficiencies, and reproductive issues. This study, thus, explored the feasibility of employing a novel polymeric ferromagnetic nanocomposite adsorbent made of low-cost, biodegradable, and ultra-permeable materials from pulp and paper sludge for adsorptive removal of hexavalent chromium (Cr6+) from synthetic wastewater. Vibrating-sample magnetometer (VSM), X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmet-Teller surface area (BET), and Fourier transform infrared (FTIR) were used to analyze the produced nanocomposite adsorbent. The Fourier transform infrared results confirmed the presence of adsorptive peaks attributed to −OH, −NH2, and FeO. Scanning electron microscopy micrographs revealed a porous adsorbent surface. XRD revealed the existence of the crystalline spinel-structured magnetite (Fe3O4) phase of iron oxide, while the saturation magnetization was established to be 26.90 emu/g. The Brunauer–Emmett–Teller analysis confirmed a slight decrease in the surface area of the nanocomposite adsorbent to 6.693 m2.g−1, compared to Fe3O4 (7.591 m2.g−1). The optimum conditions for Cr6+ removal were pH 2.0, 1.0 g/L adsorbent dose, room temperature (25°C), 120 min contact time, and 20 mg/L pollutant concentration. During removal, the Cr(VI) was adsorbed by electrostatic attraction and/or reduced to trivalent chromium Cr(III). At low starting Cr(VI) concentrations, chemisorption dominated the removal process, but as concentrations increased, physisorption became more significant. The prepared nanocomposite adsorbent presented exceptional removal efficiency of up to 92.23%, indicating that it may be useful for the adsorption of metal ions from industrial and household wastewater.

Influence of the iron-oxide mass fractions of magnetic powdered activated carbon on its hexavalent chromium adsorption performance in water

Magnetic powdered activated carbon (Mag-PAC) is an effective adsorbent to remove hexavalent chromium (Cr(VI)) from water and can be recovered for reuse. However, the tradeoff between the adsorption performance of Cr(VI) and magnetic properties of Mag-PAC remains unclear. Herein, we prepared a series of Mag-PAC adsorbents containing various iron-oxide mass fractions with FeSO4·7H2O as the precursor, using a facile wet-chemical precipitation route and conducted batch experiments to evaluate the Cr(VI) adsorption performance. Results revealed that Mag-PAC was functionalized by magnetic iron oxide comprising crystalline goethite and magnetite structures. Furthermore, its adsorption performance was highly dependent on pH and was most effective at an initial solution pH of 2. Both the sorption rate constant and Cr(VI) adsorption capacity were greatly influenced by magnetization, and they gradually decreased as the iron-oxide mass fraction increased. Among the prepared adsorbents, Mag-PAC-75 (∼32% wt iron) exhibited not only an excellent Cr(VI) adsorption performance (Langmuir adsorption capacity: 75.76 mg/g) but also effective magnetic properties (saturation magnetization: 9.66 emu/g). Coexisting anions had a negligible competitive effect on Cr(VI) removal by Mag-PAC-75 at an initial pH of 2, whereas the presence of tannic acid markedly improved the Cr(VI) elimination. The presence of trivalent chromium on the surface of Mag-PAC-75 confirmed via X-ray photoelectron spectroscopy indicated that some synergistic redox reactions may occur during the sorption process. After five regeneration cycles using NaOH, Mag-PAC-75 continued to exhibit a high Cr(VI) removal efficiency and magnetic stability. These findings indicate that optimizing the adsorption performance and magnetic properties is a key factor for realizing the practical application of Mag-PAC for Cr(VI) removal. Overall, Mag-PAC may have been a promising application prospect for Cr(VI) removal from water due to its high adsorption capacity and magnetic properties, coupled with its good reusability and magnetic stability after regeneration cycles.

Magnetic biochar from spent coffee grounds as filler in bioplastic composites

This study focuses on the synthesis of magnetic biochar derived from spent coffee grounds and their use in biodegradable pectin composite films. X-ray diffraction and Raman spectroscopy confirmed an amorphous char structure with embedded crystalline magnetite in the magnetic biochar. For the composite films, the hysteresis loops show a magnetic behavior reminiscent of a soft magnet with a low coercive field of 90 Oe and 14 % remanence. Thermogravimetric analysis revealed improved thermal stability of the composite films compared to pure pectin films. The proposed approach offers enhanced thermal properties and magnetic functionality, with potential applications in sustainable packaging, electromagnetic shielding and environmental sensing.

Irinotecan-loaded magnetite-silica core-shell systems for colorectal cancer treatment

Colorectal cancer represents a worldwide spread type of cancer and it is regarded as one of the leading death causes, along with lung, breast, and prostate cancers. Since conventional surgical resection and chemotherapy proved limited efficiency, the use of alternative drug delivery systems that ensure the controlled release of cytostatic agents possess immense potential for treatment. In this regard, the present study aimed to develop and evaluate the efficiency of a series of irinotecan-loaded magnetite-silica core–shell systems. The magnetite particles were obtained through a solvothermal treatment, while the silica shell was obtained through the Stöber method directly onto the surface of magnetite particles. Subsequently, the core–shell systems were physico-chemically and morpho-structurally evaluated trough X-ray diffraction (XRD) and (high-resolution) transmission electron microscopy ((HR-)TEM) equipped with a High Annular Angular Dark Field Detector (HAADF) for elemental mapping. After the irinotecan loading, the drug delivery systems were evaluated through Fourier-transform infrared spectroscopy (FT-IR), thermogravimetry and differential scanning calorimetry (TG-DSC), and UV–Vis spectrophotometry. Additionally, the Brunauer–Emmett-Teller (BET) method was employed for determining the surface area and pore volume of the systems. The biological functionality of the core-shells was investigated through the MTT assay performed on both normal and cancer cells. The results of the study confirmed the formation of highly crystalline magnetite particles comprising the core and mesoporous silica layers of sizes varying between 2 and 7 nm as the shell. Additionally, the drug loading and release was dependent on the type of the silica synthesis procedure, since the lack of hexadecyltrimethylammonium bromide (CTAB) resulted in higher drug loading but lower cumulative release. Moreover, the nanostructured systems demonstrated a targeted efficiency towards HT-29 colorectal adenocarcinoma cells, as in the case of normal L929 fibroblast cells, the cell viability was higher than for the pristine drug. In this manner, this study provides the means and procedures for developing drug delivery systems with applicability in the treatment of cancer.

New insights into the adsorptive characteristics of trihalomethane precursors from surface water using magnetic powdered activated carbon

Powdered activated carbon (PAC) can effectively eliminate dissolved organic matter (DOM) as a precursor of trihalomethane (THM), but its application has raised concerns regarding its separation and the overelevated formation of brominate THM species in treated water after chlorination. Although magnetic PAC (Mag-PAC) has been proposed as an easily separable adsorbent for water treatment, its removal by Mag-PAC remains unknown. In this study, a novel Mag-PAC adsorbent for removing DOM and controlling THM formation from surface water was fabricated, evaluated using batch experiments, and compared with PAC. Our results found that Mag-PAC blended the advantages of PAC and magnetic particles, having an efficient removal performance toward DOM with an adsorption capacity of 2.84–3.69 mg-C/g and good magnetic separability of 10.15 emu/g. The iron oxide coating on the carbon matrices was predominantly distributed in the presence of crystalline goethite and magnetite structures. Chemisorption was the dominant mechanism of DOM adsorption by Mag-PAC. The sorption rate of DOM was influenced by the impregnation of iron oxide, but such impregnation did not significantly affect the DOM adsorption capacity. Aromatic DOM, humic-acid and fulvic-acid like compounds were efficiently adsorbed by the Mag-PAC. Compared with PAC, Mag-PAC exhibited a higher reduction in lifetime cancer risks from THMs through the ingestion pathway by decreasing the formation potential of trichloromethane and bromodichloromethane, which generated high unit risks among various THM species. These findings highlight the potential of Mag-PAC as an effective sorbent for DOM removal to control the formation of THM in surface water.

Rapid ultrasound driven self-assembled nanoarchitectonics iron oxide-reduced graphene oxide as an anode for Li-ion battery and its electrochemical performance studies

With the scope of identifying an effective nanomaterial as an anode for Li-ion battery under economic synthesis factors, here, high crystalline mesoporous magnetite nanoparticles (m-Fe3O4 NPs) with an average diameter of 45 ± 10 nm were successfully synthesized through facile, one-pot sonoelectrochemical method in 15 min, and it was structurally anchored into sonochemically exfoliated reduced graphene oxide nanosheets (m-Fe3O4@rGO). The morphological studies through FESEM and HRTEM analysis confirm that the m-Fe3O4 were well anchored into rGO nanosheets, and it has maximum magnetic saturation value of 39 emu g−1 and high surface area of 254 m2 g−1. The performance analysis results of m-Fe3O4@rGO nanocomposite as an anode material in half-cell configuration with Li-metal had demonstrated that around 11 % enhancement in first discharge capacity (1440.79 mAh g−1 at 0.2 A g−1 current density), ~50 % increased rate capability (356 mAh g−1 at 5.0 A g−1 current density) than bare m-Fe3O4 electrode and had maintained nearly 441 mAh g−1 after 500 cycles at 2.0 A g−1 current density. These results suggest that the sonochemical method could be a better alternate method when compared to other time-consuming processes like solvothermal method where high temperature is required to fabricate effective nanocomposite for high-rate performance in real time applications of Li-ion battery.

In situ SR-XRD analysis of corrosion product formation during ‘pseudo-passivation’ of carbon steel in CO2-containing aqueous environments

In situ Synchrotron Radiation X-ray Diffraction (SR-XRD) is employed to follow the evolution of corrosion products on X65 carbon steel in a CO2-containing aqueous environment (80 °C, pH 6.3–7.3). A custom-designed flow cell is used to follow the real-time concomitant changes in electrochemical behaviour and corrosion product growth during stages of both natural and potentiodynamically driven ‘pseudo-passivation’. We show that no detectable crystalline magnetite (Fe3O4) phase forms during ‘pseudo-passivation’ across all conditions studied. Furthermore, the results suggest the significant ennoblement observed during ‘pseudo-passivation’ in these experiments can be strongly related to the accumulation of iron carbonate (FeCO3) on the steel surface.

Asymmetric nanoparticle oxidation observed in-situ by the evolution of diffraction contrast

The use of transmission electron microscopy (TEM) to observe real-time structural and compositional changes has proven to be a valuable tool for understanding the dynamic behavior of nanomaterials. However, identifying the nanoparticles of interest typically require an obvious change in position, size, or structure, as compositional changes may not be noticeable during the experiment. Oxidation or reduction can often result in subtle volume changes only, so elucidating mechanisms in real-time requires atomic-scale resolution or in-situ electron energy loss spectroscopy, which may not be widely accessible. Here, by monitoring the evolution of diffraction contrast, we can observe both structural and compositional changes in iron oxide nanoparticles, specifically the oxidation from a wüstite-magnetite (FeO@Fe3O4) core–shell nanoparticle to single crystalline magnetite, Fe3O4 nanoparticle. The in-situ TEM images reveal a distinctive light and dark contrast known as the ‘Ashby-Brown contrast’, which is a result of coherent strain across the core–shell interface. As the nanoparticles fully oxidize to Fe3O4, the diffraction contrast evolves and then disappears completely, which is then confirmed by modeling and simulation of TEM images. This represents a new, simplified approach to tracking the oxidation or reduction mechanisms of nanoparticles using in-situ TEM experiments.

Pyrogenic Carbon Improves Cd Retention during Microbial Transformation of Ferrihydrite under Varying Redox Conditions.

Fe(III) (oxyhydr)oxides are ubiquitous in paddy soils and play a key role in Cd retention. Recent studies report that pyrogenic carbon (PC) may largely affect the microbial transformation processes of Fe(III) (oxyhydr)oxides, yet the impact of PC on the fate of Fe(III) (oxyhydr)oxide-associated Cd during redox fluctuations remains unclear. Here, we investigated the effects of PC on Cd retention during microbial (Shewanella oneidensis MR-1) transformation of Cd(II)-bearing ferrihydrite under varying redox conditions. The results showed that in the absence of PC, microbial reduction of ferrihydrite resulted in Cd release under anoxic conditions and Fe(II) oxidation by oxygen resulted in Cd retention under subsequent oxic conditions. The presence of PC facilitated microbial ferrihydrite reductive dissolution under anoxic conditions, promoted Fe(II) oxidative precipitation under oxic conditions, and inhibited Cd release under both anoxic and oxic conditions. The presence of PC and frequent shifts in redox conditions (i.e., redox cycling) inhibited the transformation of ferrihydrite to highly crystalline goethite and magnetite that exhibited less Cd adsorption. As a result, PC enhanced Cd retention by 41-59% and 55-77% after the redox shift and redox cycling, respectively, while in the absence of PC, Cd retention decreased by 5% after the redox shift and increased by 11% after redox cycling. Sequential extraction analysis revealed that 63-78% of Cd was associated with Fe minerals, while 3-12% of Cd was bound to PC, indicating that PC promoted Cd retention mainly through inhibiting ferrihydrite transformation. Our results demonstrate the great impacts of PC on improving Cd retention under dynamic redox conditions, which is essential for applying PC in remediating Cd-contaminated paddy soils.

Facile one-pot rapid sonoelectrochemical synthesis of mesoporous magnetite nanospheres: A Chimie Douce approach

In this study, mesoporous Magnetite (Fe3O4) nanospheres have been synthesized quickly via facile sonoelectrochemical method. The scope of this study is to obtain high yield of active Fe3O4 nanoparticles in a tunable structural morphology with reduced cost, energy, and synthesis time without compromising its quality. The coupling of the electrochemical method with ultrasound could influence higher mass transfer rate, thereby leading to rapid formation of magnetite. Studies on understanding the role of additive and stabilizer have been carried out. Further, the influence of ultrasound amplitude and irradiation time has been examined. Under constant electrochemical parameters, the formation of magnetite of required properties is achieved with added additive and stabilizer under 60% ultrasound amplitude at 15 min of irradiation time. The prepared magnetite nanoparticles under optimized synthesis parameters were spherical in shape with a narrow size distribution of 30–80 nm, mesoporous in nature, and with a surface area of 121.87 m2g-1. The high value of saturation magnetization (65.33 emug−1) conjointly discloses the near superparamagnetic nature. The elemental composition of highly crystalline magnetite nanoparticles with good stability behavior has been demonstrated by deep characterization techniques.

PH-responsive glycine functionalized magnetic iron oxide nanoparticles for SARS-CoV-2 RNA extraction from clinical sample.

The recent outbreak of the novel corona virus disease 2019 (COVID-19) has been made a serious global impact due to its high infectivity and severe symptoms. The Severe Acute Respiratory Syndrome (SARS-CoV-2) RNA extraction is considered as one of the most important steps in COVID-19 detection. Several commercially available kits and techniques are currently being used for specific extraction of SARS-CoV-2 RNA. However, such methods are time consuming and expensive due to the requirement of trained labors, and several chemical reagents. To overcome the mentioned limitations, magnetic RNA adsorption methodology of glycine functionalized iron oxide nanoparticles (GNPs) was established. It showed an efficient potential in SARS-CoV-2 RNA extraction due to pH responsive nature of GNPs. The highly magnetic pH responsive GNPs were synthesized by one-pot co-precipitation method. Random morphology and average 20 nm size of GNPs were denoted by Transmission Electron Microscopy (TEM). X-ray diffractometer (XRD) showed the crystalline magnetite nature. Fourier transform infrared spectroscopy (FT-IR) and UV–visible spectrometry confirmed the presence of glycine on the surface of magnetic nanoparticles. Furthermore, the magnetic nature and thermal properties of GNPs were examined by vibrating sample magnetometer (VSM) and thermo-gravimetric analysis (TGA), respectively. In this study, glycine performed the role of RNA adsorbent. The adsorption of RNA onto the surface of GNPs was achieved in acidic medium (pH 6). In contrary, the elution of RNA from the surface of GNPs was achieved in basic medium (pH 8). The purity of obtained RNA was analyzed by UV–visible spectrometry. Further, the obtained RNA was examined for the presence of SARS-CoV-2 specific Envelope (E), RNA dependent RNA polymerase (RDRP) and Nucleocapsid (N) genes using an RT-PCR analysis. It showed the sudden rise in amount of these genes after 25 cycles of RT-PCR and hence indicated the efficient RNA extraction by GNPs. Agarose gel electrophoresis was used for validation of the quantity and quality of RNA extracted from SARS-CoV-2 patient’s sample. The reusability studies of GNPs were performed by monitoring the repeated use of GNPs for SARS-CoV-2 RNA extraction. This method possesses potential role in the field of disease diagnosis. The extraction results of RNA from SARS-CoV-2 patient’s sample indicated that the GNPs have an outstanding property over the current existing extraction protocols. It leads to the new advancements in extraction and detection of RNA.Graphical Graphical abstract of the pH responsive SARS-CoV-2 RNA extraction by using glycine functionalized magnetic iron oxide nanoparticles (GNPs) which were prepared by modified cost effective one pot chemical synthesis method. Prepared GNPs were characterized by XRD, FT-IR and UV-Visible spectrometry, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Glycine present on the surface of nanoparticles (NPs) played an important role in pH responsive RNA extraction procedure. When nanoparticles added in acidic (pH < 7) medium, glycine gained positive surface charge hence overall surface charge of NPs became positive. Thereby SARS-CoV-2 RNA adsorption/binding occurred on the surface of GNP. Later, the RNA-GNP complex was separated by an external magnet. Separated complex was added in basic (pH > 7) medium to elute RNA from GNP. This phenomenon occurred due to surface negative charge of glycine that caused charge repulsion with RNA. Eluted RNA was examined qualitatively and quantitatively by RT-PCR, nanodrop technique and agarose gel electrophoresis. Results were compared with kit based extracted RNA. Supplementary InformationThe online version contains supplementary material available at 10.1007/s10853-022-07464-6.

Systematic Investigation of Structural, Morphological, Thermal, Optoelectronic, and Magnetic Properties of High-Purity Hematite/Magnetite Nanoparticles for Optoelectronics.

Iron oxide nanoparticles, especially hematite (α-Fe2O3) and magnetite (Fe3O4) have attained substantial research interest in various applications of green and sustainable energy harnessing owing to their exceptional opto-magneto-electrical characteristics and non-toxicity. In this study, we synthesized high-purity hematite and magnetite nanoparticles from a facile top-down approach by employing a high-energy ball mill followed by ultrasonication. A systematic investigation was then carried out to explore the structural, morphological, thermal, optoelectrical, and magnetic properties of the synthesized samples. The experimental results from scanning electron microscopy and X-ray diffraction corroborated the formation of highly crystalline hematite and magnetite nanoparticles with average sizes of ~80 nm and ~50 nm, respectively. Thermogravimetric analysis revealed remarkable results on the thermal stability of the newly synthesized samples. The optical studies confirmed the formation of a single-phase compound with the bandgaps dependent on the size of the nanoparticles. The electrochemical studies that utilized cyclic voltammetry and electrochemical impedance spectroscopy techniques verified these iron oxide nanoparticles as electroactive species which can enhance the charge transfer process with high mobility. The hysteresis curves of the samples revealed the paramagnetic behavior of the samples with high values of coercivity. Thus, these optimized materials can be recommended for use in future optoelectronic devices and can prove to be potential candidates in the advanced research of new optoelectronic materials for improved energy devices.

Diagenesis of clastic ores of the Ishkininо Co-bearing massive sulfide deposit (Southern Urals): Mineralogical-geochemical data and thermodynamic modeling

Research subject. The transformed clastic ores (ore diagenites) of the Ishkinino Co-bearing massive sulfide deposit hosted by serpentinites of the Main Uralian Fault Zone.Materials and methods. The structures and textures of the ores were stu died. The trace element contents of sulfides and oxides were determined using LA ICP MS. The physical and chemical modeling of the diagenetic formation of accessory As minerals was conducted using the Selektor program package. Results. The clastic ores are transformed gravelites with angular and rounded clasts of serpentinites, sulfides and chromite in the psammitic matrix of the same mineral composition. No hydrothermal minerals remain in gravelites; they are replaced by crystalline pyrite-2, porous pyrite-3, anhedral pyrite-4, pyrrhotite, chalcopyrite and magnetite. Chalcopyrite and magnetite replace all sulfides, sulfarsenides, chromite and gangue minerals. Chromite occurs as fragmented crystals or inclusions into serpentinite clasts. The matrix hosts euhedral cobaltite crystals with nickeline, gersdorffite and native gold inclusions. Crystalline pyrite-2 is characterized by higher Mn, Co, Ni, Cu and Zn contents. Porous pyrite-3 exhibits higher Co, Cu and Se contents. Anhedral pyrite-4 is enriched in most trace element contents in comparison with other sulfides and pyrite generations. Chalcopyrite is characterized by higher contents of Zn and Se. Pyrrhotite contains the highest Ni and hi gher Co contents.Conclusions. The main trace elements in the ores of the deposit (Co and Ni), as well as Cu, Zn and Mn, are hosted not only in sulfides, but also in oxides. Thus, chromite contains Zn and Ni, while magnetite contains Mn and Cu. Selenium occurs in all sulfides in similar quantities. Tellurium is mostly concentrated in pyrite-4. A comparative analysis of our results with those reported on other massive sulfide deposits showed that the serpentinite-sulfide gravelites of the Ishkinino deposit had been intensely transformed during diagenesis, which resulted in low trace element contents in diagenetic sulfides. The diagenetic alteration of clastic ores led to the formation of authigenic cobaltite, gersdorffite, nickeline and native gold as a result of trace element release from primary hydrothermal minerals. Thermodynamic mode ling showed the possibility of formation of As-bearing minerals (in particular, nickeline) at temperatures of 200°C and below.

Iron speciation in soil size fractions under different land uses

Iron (Fe) (oxyhydr)oxides represent a significant phase for the organic carbon (OC) stabilization. Due to their high surface areas, short-range-ordered Fe minerals, like ferrihydrite, show a higher ability to stabilize OC than crystalline secondary minerals, like lepidocrocite, goethite, and magnetite. However, how Fe phases and their crystallinity relate to soil organic matter (SOM) composition is still not completely known. We investigated Fe solid phase speciation in two soil particle size fractions (i.e., fine sand — FSa — and fine silt and clay — FSi + Cl —), isolated from coniferous (CF) and broadleaved forest soils (BF), grassland soils (GL), and technosols (TS). All samples were characterized by Fe K-edge extended X-ray absorption fine structure (EXAFS) and X-ray diffraction, and a subset by 57Fe Mössbauer spectroscopy. Further, ramped combustion thermal analyses (coupled differential scanning calorimetry (DSC) and CO2 evolved gas analysis (CO2-EGA)) were used to evaluated SOM stability. With the only exception of TS, goethite was the main Fe phase in FSa fractions, whereas less crystalline phases (i.e., ferrihydrite, based on EXAFS) dominated the FSi + Cl fractions. The proportion of goethite and ferrihydrite in both fractions decreased with increasing OC content, while that of Fe(III)-SOM in FSa increased with increasing OC content. Mössbauer and EXAFS data clearly indicated a presence of hematite in GL soils. Our data suggest that more crystalline Fe forms, like goethite and hematite, may be important for OC abundance in the FSa fraction and in soils with high OC contents, like GL. Thermal analysis showed the dominance of mineral associated organic matter in low-OC soils, and of plant residues in high-OC soils. As a whole, we posit that the FSi + Cl fractions contain Fe phases of less crystallinity because of presumed association with SOM, and that SOM in the FSi + Cl fraction is also more thermodynamically stable than in FSa, although differences are observed across land uses. Our observations suggest that the nature of Fe-SOM interactions can vary substantially with soil particle size and land use, which has important implication for SOM persistence.

Initial stage of corrosion formation for X70 pipeline external surface in acidic soil (peat) environment

Organic peat with a pH range from 4.5 to 5.5 was utilised as an alternate corrosive medium in this investigation to produce a naturally acidic environment that may promote surface deterioration on the X70 pipeline exterior surface. The physical and chemical properties of the corrosion product during the initial stage of corrosion formation have been analysed using several analytical techniques, including Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX), X-ray Diffraction analysis (XRD), and Raman spectroscopy. As the external surface is exposed to the acidic soil environment, the oxide layer is formed and initiated by intergranular corrosion on the elongated grain boundaries, leading to various shapes and sizes of corrosion products. After 60 days of exposure, XRD revealed that the corrosion products formed were consists of amorphous oxides and low-intense crystalline phases, namely lepidocrocite, γ-FeOOH (2θ≈26.85°), goethite, α-FeOOH (2θ≈21.75°), hematite, Fe2O3 (2θ≈35°) and magnetite, Fe3O4 (2θ≈38°). The morphology structure and composition analysis by SEM-EDX indicated that the corrosion products compositions are mainly contributed by Fe (55%) and O (25.99%), with some trace of C, Ca and Si compounds. Finally, the molecular structure for the micro-oxide coating around the external surface of this X70 pipeline is mainly dominated by species of lepidocrocite (γ-FeOOH), goethite (α-FeOOH), hematite (α-Fe2O3), and magnetite (Fe3O4). Overall, it can be concluded that a significant oxide layer formation by four types of iron oxides species [lepidocrocite (γ-FeOOH), goethite (α-FeOOH), hematite (α-Fe2O3), and magnetite (Fe3O4)] is observed in this work. This study also indicates that the corrosion product of the external surface of the X70 pipeline could be formed via chemisorption and physisorption process by the interaction between the acidic soil particles and the metal surface.

Formulation and in-vitro evaluations of doxorubicin loaded polymerized magnetic nanocarriers for liver cancer cells

BackgroundLiver cancer is the third most common cause of cancer deaths globally. Regrettably, its treatment is limited due to insufficient treatment options and side effects caused by chemotherapy which is the common treatment method. Thus, the main aim of the study was the synthesis of nanocarriers composed of dextran modified iron oxide nanoparticles for doxorubicin delivery (IONP@Dex@DOX) in liver cancer treatment to overcome the limitations of chemotherapy MethodsThe IONP@Dex nanocarriers were first synthesized via solvothermal method and then characterized using several analytical instruments. Significant findingsXRD and HR–TEM demonstrated spherical core-shelled, well-dispersed, and highly crystalline magnetite (311) nanocarriers with sizes ranging between 10 and 15 nm. Both IONPs and IONP@Dex nanocarriers (42.50 and 33.40 emu/g) exhibited a saturation magnetization high enough to be magnetically controlled throughout the body. A biocompatibility of above 80% was confirmed through in-vitro cell viability studies using the 3-(4,5-dimethylthiazole-2-yl)2,5-diphenyltetrazolium bromide (MTT)-based assay at 24 and 48 h against HEK293T and HepG2 cells. The results demonstrated nontoxic nanoparticles with cell viability above 80%. Interestingly, upon drug conjugation, a drastic reduction in the viability of cancerous cells was observed. Exposure of cells treated with the drug loaded nanocarrier to an external magnetic field (EMF) demonstrated an additional decrease in cell viability.

Paclitaxel-Loaded Magnetic Nanoparticles Based on Biotinylated N-Palmitoyl Chitosan: Synthesis, Characterization and Preliminary In Vitro Studies.

A considerable interest in cancer research is represented by the development of magnetic nanoparticles based on biofunctionalized polymers for controlled-release systems of hydrophobic chemotherapeutic drugs targeted only to the tumor sites, without affecting normal cells. The objective of the paper is to present the synthesis and in vitro evaluation of the nanocomposites that include a magnetic core able to direct the systems to the target, a polymeric surface shell that provides stabilization and multi-functionality, a chemotherapeutic agent, Paclitaxel (PTX), and a biotin tumor recognition layer. To our best knowledge, there are no studies concerning development of magnetic nanoparticles obtained by partial oxidation, based on biotinylated N-palmitoyl chitosan loaded with PTX. The structure, external morphology, size distribution, colloidal and magnetic properties analyses confirmed the formation of well-defined crystalline magnetite conjugates, with broad distribution, relatively high saturation magnetization and irregular shape. Even if the ability of the nanoparticles to release the drug in 72 h was demonstrated, further complex in vitro and in vivo studies will be performed in order to validate the magnetic nanoparticles as PTX delivery system.

Steering the synthesis of Fe3O4 nanoparticles under sonication by using a fractional factorial design

Superparamagnetic iron oxide nanoparticles (MNPs) have the potential to act as heat sources in magnetic hyperthermia. The key parameter for this application is the specific absorption rate (SAR), which must be as large as possible in order to optimize the hyperthermia treatment. We applied a Plackett-Burman fractional factorial design to investigate the effect of total iron concentration, ammonia concentration, reaction temperature, sonication time and percentage of ethanol in the aqueous media on the properties of iron oxide MNPs. Characterization techniques included total iron content, Fourier Transform Infrared Spectroscopy, X-Ray Diffraction, High Resolution Transmission Electron Microscopy, and Dynamic Magnetization. The reaction pathway in the coprecipitation reaction depended on the initial Fe concentration. Samples synthesized from 0.220 mol L−1 Fe yielded magnetite and metastable precipitates of iron oxyhydroxides. An initial solution made up of 0.110 mol L−1 total Fe and either 0.90 or 1.20 mol L−1 NH3(aq) led to the formation of magnetite nanoparticles. Sonication of the reaction media promoted a phase transformation of metastable oxyhydroxides to crystalline magnetite, the development of crystallinity, and the increase of specific absorption rate under dynamic magnetization.

Facile Green Synthesis of Iron Oxide Nanoparticles Using Phoenix dactylifera L. Seed Extract and Their Antibacterial Applications

Aim: The synthesis methods of iron oxide nanoparticles (IONPs) have got great attention in recent years, due to their variety in physicochemical properties and applications. This study aimed for the green synthesis of the IONPs using an aqueous extract of P. dactylifera L. seeds for its antibacterial applications.&#x0D; Methodology: IONPs were prepared in an aqueous seed extract of P. dactylifera L. The physicochemical characterisations were performed with transmission electron microscopy (TEM) to study the shape of obtained nanoparticle, energy-dispersive spectroscopy (EDS) for elemental confirmation of iron and oxygen, dynamic light scattering (DLS) for particles size measurement, vibrating sample magnetometer (VSM) for saturation magnetisation, Infrared spectroscopy (FTIR) for chemical confirmation of function groups and X-ray diffraction (XRD) for crystalline nature. The polyphenols contents were also determined; we suggest that the presence of phenolic compounds is the key element involved in the formation and the stabilisation of IONPs. Antibacterial activity was determined using disc diffusion assay and minimum inhibitory concentration (MIC) of the IONPs were determined by broth dilution assay.&#x0D; Results: The biosynthesised IONPs showed crystalline magnetite spherical morphologies with average diameter 30 nm. Discs with all the concentrations of IONPs tested in this study (10 - 100 ug.mL-1) showed antibacterial activity against bacterial strains tested (Staphylococcus epidermidis, Klebsiella pneumoniae and Pseudomonas aeruginosa). MIC values were found to be 30 ug.mL-1, 50 ug.mL-1 and 60 ug.mL-1 for S. epidermidis, K. pneumoniae and P. aeruginosa respectively.&#x0D; Conclusion: The biosynthesis of IONPs has provided, reliable, safe, simple and eco-friendly method. Hence, this study has focused on biological method of synthesis of IONPs. The IONPs synthesized in this study can be used as the therapeutic agents against bacteria.

Decrease in the Crystallite Diameter of Solid Crystalline Magnetite around the Curie Temperature by Microwave Magnetic Fields Irradiation.

A decrease in the crystallite diameter of ferrites irradiated with microwaves has been considered as a non-thermal effect of so-called de-crystallization; however, its mechanism has not been elucidated. We hypothesized that a decrease in the crystallite diameter is caused by interaction between the ordered spins of ferrite and the magnetic field of microwaves. To verify this, we focused on magnetite with a Curie temperature of 585 °C. Temperature dependence around this temperature and time dependence of the crystallite diameter of the magnetite irradiated with microwaves at different temperatures and durations were investigated. From the X-ray diffraction data, the crystallite diameter of magnetite exhibited a minimum value at 500 °C, just below the Curie temperature of magnetite, where the energy loss of the interaction between magnetite’s spins and the microwaves takes the maximum value. The crystallite diameter exhibited a minimum value at 5 min irradiation time, during which the microwaves were excessively absorbed. Transmission electron microscopy observations showed that the microstructure of irradiated magnetite in this study was different from that reported previously, indicating that a decrease in the crystallite diameter is not caused by de-crystallization but its similar phenomenon. A decrease in coercivity and lowering temperature of Verwey transition were observed, evidencing decreased crystallite diameter. This study can thus contribute to the development of the theory of a non-thermal effect.