Search

The utilization of nanoparticles to enhance bacterial activity and boost hydrogen production in fermentation processes has gained significant attention due to their unique properties such as high specific surface area and quantum size. This research aimed to improve the biohydrogen yield from food waste by adding iron oxide nanoparticles (Fe 3 O 4) at various concentrations (50, 75, 100, 150, and 200 mg/l) and titanium dioxide (TiO 2) at different amounts (25–150 mg/l) to a single-stage hybrid (dark/photo) fermentation reactor. After obtaining the optimal amount of these two nanoparticles, the effect of synergic addition of nanoparticles on hydrogen production yield, was investigated at ratios of Fe 3 O 4 /TiO 2 = 50/50 and 100/50 mg/mg. At the ratio of Fe 3 O 4 /TiO 2 = 100/50, the cumulative hydrogen production and yield of hydrogen have increased from 1613 to 3392 ml and 101.60 to 213.66 mlH 2 /gVS, respectively, compared to the control experiment. We also found that the COD removal rate has enhanced from 28% to 40.1%. In the optimal value, the bacterial growth lag phase has also remarkably decreased from 8.19 to 4.81 h. • Synergic application of TiO 2 and Fe 3 O 4 significantly increased biohydrogen purity and production yield. • TiO 2 played an important role in the activity of bacteria in the photo fermentation process. • Fe 3 O 4 played an important role in the dark fermentation system. • Nanoparticles may act as a scaffold for enzyme and substrate binding. • Optimal nanoparticle concentration may differ for different bioreactors. [ABSTRACT FROM AUTHOR]

An advanced version of the solution combustion synthesis (SCS) method was developed to prepare iron oxide (IO) nanoparticles, through controlling the agglomeration, size and shape of nanoparticles by assisting a cationic surfactant, "cetyltrimethylammonium bromide (CTAB)" and ethanol. Various IO nanoparticles were prepared in the presence of different CTAB:ethanol molar compositions of 0:0, 0.27:0, 0.55:0, 0.27:17.1, 0.55:17.1 and 0.82:17.1. The morphological evolution from agglomerated-shape particles to the well-dispersed as well as the size- and shape-controlled particles depended directly on the CTAB:ethanol molar composition. A shift from ferromagnetic behavior to superparamagnetic was observed by the application of CTAB along with ethanol, where the lowest blocking temperature (T b , 60 K), highest saturation magnetization (M s , 83.5 emu g−1), zero coercivity and remanance magnetization were revealed for the particles prepared by CTAB:ethanol molar compositions of 0.55:17.1. These particles showed an acceptable specific absorption rate (SAR) value (320 W g−1) as well as no obvious hemolytic and cytotoxic effects. This work provides new insights into advancing the SCS method and thus controlling the morphology, size and shape of metal oxide nanoparticles. [Display omitted] • Controlling the agglomeration, size and shape of nanoparticles in SCS method. • Structural and magnetic properties of particles depended on the CTAB:ethanol ratio. • The agglomerated-free, size- and shape-controlled IO-EC2 structure was developed. • IO-EC2 represented an acceptable SAR value, and no hemolytic and cytotoxic effects. [ABSTRACT FROM AUTHOR]

Multicore magnetic iron oxide nanoparticles, nanoflowers (NFs), have potential biomedical applications as efficient mediators for AC-magnetic field hyperthermia and as contrast agents for magnetic resonance imaging due to their strong magnetic responses arising from complex internal magnetic ordering. To realise these applications amenable surface chemistry must be engineered that maintain particle dispersion. Here a catechol-derived grafting approach is described to strongly bind polyethylene glycol (PEG) to NFs and provide stable hydrogen-bonded hydrated layers that ensure good long-term colloidal stability in buffers and media even at clinical MRI field strength and high concentration. The approach enables the first comprehensive study into the MRI (relaxivity) and hyperthermic (SAR) efficiencies of fully dispersed NFs. The predominant role of internal magnetisation dynamics in providing high relaxivity and SAR is confirmed, and it is shown that these properties are unaffected by PEG molecular weight or corona formation in biological environments. This result is in contrast to traditional single core nanoparticles which have significantly reduced SAR and relaxivity upon PEGylation and on corona formation, attributed to reduced Brownian contributions and weaker NP solvent interactions. The PEGylated NF suspensions described here exhibit usable blood circulation times and promising retention of relaxivity in-vivo due to the strongly anchored PEG layer. This approach to biomaterials design addresses the challenge of maintaining magnetic efficiency of magnetic nanoparticles in-vivo for applications as theragnostic agents. Application of multicore magnetic iron-oxide nanoflowers (NFs) as efficient mediators for AC-field hyperthermia and as contrast agents for MR imaging has been limited by lack of colloidal stability in complex media and biosystems. The optimized materials design presented is shown to reproducibly provide PEG grafted NF suspensions of exceptional colloidal stability in buffers and complex media, with significant hyperthermic and MRI utility which is unaffected by PEG length, anchoring group or bio-molecular adsorption. Deposition in the selected pancreatic tumour model mirrors liposomal formulations providing a quantifiable probe of tissue-level liposome deposition and relaxivity is retained in the tumour microenvironment. Hence the biomaterials design addresses the longstanding challenges of maintaining the in vivo magnetic efficiency of nanoparticles as theragnostic agents. [Display omitted] [ABSTRACT FROM AUTHOR]

Oxide materials are important for gas sensing applications. Unfortunately, most of the synthesis methods use many toxic chemicals and need long calcination at high temperatures. Thus, developing simple and green synthesis processes, which can be performed fast and at low temperatures, is imperative for both industrial manufacturers and our environment. Here, our fast and green synthesis method based on low-power laser sintering for producing FeO x (with Fe 2 O 3 as the main composition) is presented. Besides, FeO x particles were decorated on reduced graphene oxide (RGO) to form a resistive sensor. Notably, our FeO x material can reduce the response of RGO toward acidic gas (NO 2) but it enhances the RGO response toward the basic NH 3 gas. Particularly, our hybrid FeO x /RGO sensor can detect NH 3 gas at above 2 ppm under dry and humidified conditions (<85 % RH). That effect of FeO x is found due to the formation of alpha-phase Fe 2 O 3 which acts as a p-type semiconductor, which is explored and explained in the discussion section. Finally, our findings not only reveal the potential of our hybrid sensing materials for practical NH 3 sensing applications but also confirm the usefulness of laser-sintering to produce catalytic oxide materials environmentally friendly and at low cost. [Display omitted] • Fast and green production method of iron oxides (Fe 3 O 4 or Fe 2 O 3) is reported. • FeO x was directly formed on RGO resistive gas sensors via laser sintering. • p-type FeO x tuned the sensing behavior of RGO materials toward NH 3 basic gas. • The hybrid FeO x /RGO sensor can work at RT and under a wide humidity range. [ABSTRACT FROM AUTHOR]

Nanofluid-based direct absorption of solar heat results in thermal efficiencies superior to conventional solar thermal technology. In addition, convection of nanofluid can be sustained pump-free in the collector. In this article, we study an aqueous magnetic nanofluid capable to establish the photothermal convection in a lab-scale direct absorption solar collector equipped with a solenoid. The nanofluid consisted of 60-nm Fe 2 O 3 particles dispersed in distilled water at concentration in the range 0.5% wt.-2.0% wt. An empirical model of the photothermal convection was developed based on the experiments. The model accounted for magnetic and thermophoretic forces acting within the nanofluid. The nanofluid with up to 2.0% wt. iron oxide nanoparticles obtained the velocity of ∼ 5 mm/s under the magnetic field of up to 28 mT. This resulted in the maximum thermal efficiency of the collector equal to 65%. [Display omitted] • Nanofluid-based direct absorption solar collector is studied. • Nanofluid is produced with 0.5% and 2.0% of Fe 2 O 3 nanoparticles. • Magnetic field up to 28 mT is applied to nanofluid. • Photothermal convection is established in the fluid with the velocity of 2-5 mm/s. • Maximum thermal efficiency of the collector is 65%. [ABSTRACT FROM AUTHOR]

Controlled spatial arrangements of superparamagnetic iron oxide nanoparticles (SPIONs) in complex nanostructures determine fine tuning of physico-chemical properties which, in turn, may lead to new practical applications. We report here on newly observed properties of hierarchical SPIONs nanostructure with bundle-like morphology, also known as nanobundles. Colloidal chemical processes and sol-gel synthesis were used for the synthesis of nanobundles, i.e. i) self-assembly of SPIONs into magnetic nanoparticle clusters, ii) their magnetic assembly to the nanochains, and finally iii) formation of bundle-like hierarchical nanostructure. An XRPD measurements show spinel crystal structure of maghemite/magnetite nanoparticles, EDS analysis reveals Fe, Si and O as main elements whereas SEM/TEM analysis show silica-coated magnetic nanoclusters (∼100 nm) and their hierarchical assemblies with bundle-like morphology of ∼8 μm length and ∼1 μm width. TEM analysis revealed core-shell nature of iron oxide nanoparticle clusters with their size of around 80 nm that were coated by an amorphous silica shell with thickness of ∼15 nm. The nanoclusters in the core are constructed of maghemite/magnetite nanoparticle assembly with primary iron oxide nanoparticle size about 10 nm. The magnetization M data as a function of an applied external magnetic field H were successfully fitted by the Langevin function, whence the magnetic moment μ p = 19256 μ B , and the diameter d = 9.6 nm of nanoparticles were determined. Microsized bundle-like particles are superparamagnetic, magnetically guidable and possess high transverse relaxivity of r 2 = 397.8 mM−1s−1. Magnetic properties and such high value of transverse relaxivity holds promise for nanobundles application in MRI imaging (MRI contrast agent), as nanobundles may enhance the magnetic field in their surroundings and enhance proton relaxation processes. Our nanobundles can open new opportunities in the biomedical applications, magnetic separation, photonic crystals and magnetic liquid manipulation and can be inspiration for synthesizing novel self-assembled nanoparticle structures. [ABSTRACT FROM AUTHOR]

[Display omitted] • VFAs can be obtained from an aqueous solution derived by the fermentation of food waste; • Their recovery is pivotal for economic and environmental reasons; • Iron oxide NPs with functionalization or not showed low reproducible results; • Liquid-liquid extraction can be used showing higher efficiency; • the use of oleic acid presented extraction capacity up to 97% and good reproducibility. The extraction of volatile fatty acids (VFAs) from an aqueous solution derived by fermentation of food waste is a key challenge in the context of the circular economy, thanks to their high economic and environmental impact due to their wide-ranging use in various industrial fields. In this work, we compared two different extraction methods: one novel and one classical. Firstly, iron oxide nanoparticles of around 10 nm were prepared and used as they are or functionalised using (3-Aminopropyl)triethoxysilane) (APTES) molecules, adipic acid and oleic acid. This was compared with a traditional industrial method (liquid–liquid extraction) that can guarantee high extraction of VFAs with high reproducibility. Indeed the use of dichloromethane, hexane, methyl tert -butyl ether and oleic acid presented extraction values of up to 30 % while iron oxide NPs showed results with low reproducibility. The comparison demonstrated the use of oleic acid as a promising solvent for liquid–liquid extraction of VFAs. [ABSTRACT FROM AUTHOR]

Flexible supercapacitors (SCs) are pivotal in the development of wearable and portable electronic devices because of their exceptional power density, high charge/discharge rates, extended cycle life, lightweight, and flexibility. Graphene (G)-based macroscopic materials, such as one-dimensional fibers, two-dimensional films, and three-dimensional aerogels, exhibit a large specific surface area, low mass, excellent flexibility, and high conductivity. These properties make them highly suitable for use as flexible electrode materials in SCs. However, the low energy density of G-based materials hinders their application in certain fields. Iron oxide (Fe 2 O 3) has garnered considerable attention as a negative electrode material because of its low cost, high theoretical capacity, and environmentally friendly nature. However, its practical application is limited because of its poor cycling stability, easy agglomeration, and low electrical conductivity. The combination of G with Fe 2 O 3 to form a composite material not only addresses the issues of volume change and agglomeration associated with Fe 2 O 3 , but also establishes a robust conductive network that improves the electrochemical performance of composite electrodes. Therefore, the construction of SCs using Fe 2 O 3 /G composite electrodes has gained considerable research attention in recent years. We present a comprehensive review of the recent progress in the design of Fe 2 O 3 /G composites as electrode materials for flexible SCs. In addition, we discuss the current challenges and future prospects associated with the use of Fe 2 O 3 /G composites in flexible SCs. [Display omitted] • Recent progress in the design of iron oxide/graphene composites as electrode materials for flexible SCs is reviewed. • The fabrication methods are discussed in depth to provide insight into various development strategies. • The design strategies of iron oxide/graphene composites with different dimensions were comprehensively discussed. • Challenges in iron oxide/graphene composites-based flexible supercapacitors development were described. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles in general, and iron oxide nanoparticles in particular, have been studied extensively during the past 20 years for numerous biomedical applications. The main applications of these nanoparticles are in magnetic resonance imaging (MRI), magnetic targeting, gene and drug delivery, magnetic hyperthermia for tumor treatment, and manipulation of the immune system by macrophage polarization for cancer treatment. Recently, considerable attention has been paid to magnetic particle imaging (MPI) because of its better sensitivity compared to MRI. In recent years, MRI and MPI have been combined as a dual or multimodal imaging method to enhance the signal in the brain for the early detection and treatment of brain pathologies. Because magnetic and iron oxide nanoparticles are so diverse and can be used in multiple applications such as imaging or therapy, they have attractive features for brain delivery. However, the greatest limitations for the use of MRI/MPI for imaging and treatment are in brain delivery, with one of these limitations being the brain-blood barrier (BBB). This review addresses the current status, chemical compositions, advantages and disadvantages, toxicity and most importantly the future directions for the delivery of iron oxide based substances across the blood-brain barrier for targeting, imaging and therapy of primary and metastatic tumors of the brain. Magnetic forces could be used in the controlled delivery of injected magnetic iron oxide nanoparticles (IONPs) for imaging, targeting and treatment of brain tumors. Unlabelled Image [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H 2 O 2) is a vital messenger molecule facilitating signal transmission within cellular systems. The accurate quantification of H 2 O 2 in complex environments, such as human serum, is instrumental in elucidating its diverse biological functions. In this study, we present the development of a robust electrode platform by integrating hemoglobin onto iron oxide (Fe 3 O 4) nanoparticles and reduced graphene oxide (rGO) as a conducting support for the sensitive detection of H 2 O 2 in human serum. The Fe 3 O 4 /rGO nanocomposite was synthesized via a facile single-step thermolysis reaction in the presence of oleylamine. Transmission electron microscopy (TEM) analysis revealed the formation of highly monodisperse Fe 3 O 4 nanoparticles that were uniformly dispersed over the reduced graphene surface. The rGO surface provided abundant active sites (Fe 3 O 4) for H 2 O 2 sensing. Consequently, the resulting Hb/Fe 3 O 4 @rGO modified electrode exhibited a wide linear range of H 2 O 2 concentrations from 1.5 to 2684 µM, demonstrating high sensitivity and low detection limit. Further characterization of the Hb/Fe 3 O 4 @rGO/GC electrode revealed a high surface coverage (τ = 3.0 × 10−9 mol cm−2), charge transfer coefficient (α = 0.83), and electron transfer rate constant (k s = 1.33 s−1). Subsequently, the Hb/Fe 3 O 4 @rGO/GC sensor probe was employed to analyze H 2 O 2 in real human serum samples, demonstrating excellent recovery rates ranging from 99.8 % to 104.0 %. The nanocomposite material, designed through the innovative combination of graphene oxide reduction, Fe 3 O 4 nanoparticle decoration, and oleylamine amide/amine bonding, serves as an excellent electrode material for H 2 O 2 concentration sensing. Thus, this study presents a promising platform for the future determination of H 2 O 2 biomarkers in clinical settings. [Display omitted] [ABSTRACT FROM AUTHOR]

• Experiments are performed in both CSS and MSS at different water depths in coated and uncoated absorber. • Increase in water depth decreases the fresh water generation from both cases. • The fresh water produced from CSS and MSS are 3.85 and 6.03 kg/m2 respectively. • The thermal and exergy efficiencies are found as 47.67 and 4.53 % respectively using the MSS. • CPL of fresh water produced is lowered by 29.96 % than the SS using uncoated absorber. The quantity of drinkable water that is easily accessible is dwindling at an extremely quick pace. An extra degree of complication has been added to the problem as a consequence of the depletion of freshwater resources brought on by human activities. The primary objective of the present study is to enhance the rate of fresh water generation through the low-cost solar desalination unit using iron oxide as coating material using different thickness of water placed in the absorber plate. The experimental results revealed that the influence of metal oxide nanoparticle as absorber coating material improved the rate of fresh water generation by 36.08 % than the conventional solar still at a minimum thickness of water as 1 cm in the absorber. The palatable fresh water generated from the SS without any absorber coating for the thickness of water as 10, 20 and 30 mm is found to be 3.85, 3.09 and 2.90 kg/m2 respectively. However, with effective coating of the absorber plate using Fe 2 O 3 nanoparticle, the cumulative daily palatable water generated from the solar still for different thickness of water as 10, 20 and 30 mm is enhanced to about 6.03, 5.36 and 4.72 kg/m2 respectively. There is a significant enhancement of about 38.47 to 60.15 % and 1.96 to 4.53 % in the daily energy, and exergy efficiencies of the solar still using coated absorber plate in the SS respectively while compared to the SS using uncoated absorber at the lowest thickness of water in the absorber of basin. Similarly, the CPL of fresh water produced from the SS using coated absorber is lowered by 29.96 % than the SS using uncoated absorber. [Display omitted] [ABSTRACT FROM AUTHOR]

Design of a multifunctional magnetic bionanosystem has become increasingly important towards advancing the future of clinical medicine. While hollow iron oxide nanoparticles with enhanced surface areas allow for more drug molecules to be attached to the particles, their relatively low saturation magnetization (M S) hinders their practicality in medicinal applications such as drug delivery and hyperthermia therapy. We demonstrate that this limitation can be overcome by utilizing 1D magnetic nanotubes that possess both enhanced surface areas and high M S. In this study, highly crystalline, tunable aspect ratio Fe 3 O 4 nanotubes have been successfully synthesized using a hydrothermal method. Magnetic measurements showed a clear Verwey transition (∼120 K) and high M S (∼75 emu/g) at 300 K, confirming the high quality of the synthesized Fe 3 O 4 nanotubes. Calorimetric experiments on randomly dispersed Fe 3 O 4 nanotubes in water with concentration of 1 mg/mL showed a large Specific Absorption Rate (SAR) value of 400 W/g for an AC magnetic field of 800 Oe, which increased to 500 W/g when the nanotubes were aligned parallel to the DC magnetic field and suspended in a 2% agar solution. Our study shows the possibility of using the Fe 3 O 4 nanotubes as a highly effective multifunctional nanoscale tool for targeted hyperthermia and on-demand drug delivery. • Hydrothermal synthesis of highly crystalline, tunable aspect ratio Fe 3 O 4 nanotubes. • Systematic study of the growth mechanism of the nanotubes. • The presence of Verwey transition and high M S (75 emu/g) at 300 K. • Nanotubes exhibited large SAR value compared to their hollow counterparts. • Dual-purpose applications in hyperthermia and on-demand drug delivery. [ABSTRACT FROM AUTHOR]

The importance of atherosclerosis is driving research to create improved diagnostic tools based on molecular imaging. Pretargeted imaging is the use of bioorthogonal probes that selectively accumulate upon reaction with a pre-modified biomolecule in vivo. To date, this very promising approach has not been applied to atherosclerosis. Neither has been the use of a single nano-radiomaterial for PET / T 1 -MR imaging of atherosclerosis. Here, we synthesized bioorthogonal nano-radiomaterials for in vivo pretargeted molecular imaging in a mouse model of atherosclerosis. Based on tetrazine-ligation, these functionalized 68Ga iron oxide nano-radiomaterials provide simultaneous PET and T 1 -MRI signals and selectively accumulate in atherosclerotic plaques in mice sequentially injected with trans-cyclooctene-modified antibodies against oxidized LDL followed by the hybrid nano-radiomaterial. Our results demonstrate the ability of this approach to unambiguously detect atherosclerosis. Furthermore, we show the first example of how hybrid imaging can be used for pretargeted bioorthogonal molecular imaging with nanomaterials. Unambiguous detection of atherosclerosis by the in vivo reaction of 68Ga iron oxide nanoparticles with anti-oxidized phospholipids antibody. Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Magnetic nanoparticles (MNP) have been developed in the recent years for various applications like cell separation, immunoassay, and drug delivery. The present study involves the synthesis of stable, biocompatible Iron oxide MNP by coprecipitation of ferric chloride and ferrous chloride with Polyethylene glycol (PEG) as a surfactant to coat the nanoparticles twice. Scanning electron microscopic (SEM) images confirm the formation of uniform MNPs of size 12–17 nm. The peak at 582.2 cm−1 in the Fourier transform infrared spectrum (FTIR) corresponds to the Fe–O bond and the peak at 1104.1 cm−1 corresponds to a characteristic peak of PEG binding to the iron core. Tumor tissues selectively targeted with MNPs when placed in a magnetic field increases the temperature of the tumor tissues. The phantom study shows that there is a minimum of 1.3 °C and a maximum of 6.7 °C rise in temperature with increasing concentration of the nanoparticles embedded in the phantoms; this proved the possibility of enhancement of thermal images using MNPs and its usage for thermal ablation of cancer. MNPs can also be used as a contrast agent for magnetic resonance imaging (MRI). [ABSTRACT FROM AUTHOR]

[Display omitted] • The nanoparticles synthesized using Terminalia catappa leaf extract gave a mixture of Fe 2 O 3 and Fe 3 O 4 nanoparticles. • Cytotoxic behavior of the synthesized nanoparticles showed attack on both the normal (HEK 293) and cervical carcinoma (Hela) cell lines. • The effectiveness of nanoparticles towards anticancer properties depends of reaction conditions. In this research, iron oxide nanoparticles were synthesized by plant-mediated method. Their optical nature, crystallinity, composition, microscopy and sizes were characterized using energy dispersive X-ray, X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy. The microscopic studies revealed spherical/polygonal morphologies with average particle size of 19.14 nm. The in-vitro cytotoxic analysis of the nanoparticles against HEK 293 normal cell lines and Human cervical (Hela) cell lines showed cell toxicity with IC 50 values 44.12 μg and 34.94 μg respectively. The antimicrobial tests showed sensitivity to some micro-organisms whereas some were resistant. In general, the nanoparticles displayed broad spectrum activity with Methicillin Resist Staphaureus (MRSA) showing the greatest growth inhibition. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel catalytic system consisted of iron oxide magnetic nanoparticle and catechol. • Catechol-generated ROS further converted to hydroxyl radical by iron. • Initiates polymerization of wide ranges of monomers in an oxygenated solution. • Magnetic, bilayer hydrogels were formed with improved mechanical property. Phenol and its derivatives are the most used polymerization inhibitors for vinyl-based monomers. Here, we reported a novel catalytic system composed of mussel inspired adhesive moiety, catechol, in combination with iron oxide nanoparticles (IONPs) to generate hydroxyl radical (OH) at pH 7.4. Catechol-containing microgel (DHM) was prepared by copolymerizing dopamine methacrylamide (DMA) and N -hydroxyethyl acrylamide (HEAA), which generated superoxide (O 2 −) and hydrogen peroxide (H 2 O 2) as a result of catechol oxidation. In the presence of IONPs, the generated reactive oxygen species were further converted to OH, which initiated free radical polymerization of various water-soluble acrylate-based monomers including neutral (acrylamide, methyl acrylamide, etc.), anionic (2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt), cationic ([2-(methacryloyloxy)ethyl]trimethylammonium chloride), and zwitterionic (2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide) monomers. Compared with the typical free radical initiating systems, the reported system does not require the addition of extra initiators for polymerization. During the process of polymerization, a bilayer hydrogel was formed in situ and exhibited the ability to bend during the process of swelling. The incorporation of IONPs significantly enhanced magnetic property of the hydrogel and the combination of DHM and IONPs also improved the mechanical properties of these hydrogels. [ABSTRACT FROM AUTHOR]

Understanding water absorbency in paper is challenging as fibre swelling and out-of-plane deformation occur simultaneously during liquid imbibition. Liquid absorption is commonly accessed by gravimetric tests, which provides limited information on the local spatial and temporal distribution of fluid in the substrate. In this work, we developed iron tracers to map liquid imbibition in paper by in situ precipitation of iron oxide nanoparticles during passage of the wetting front. The iron oxide tracers were found to be robustly attached to the cellulosic fibres. After liquid absorption tests, absorbency was investigated by mapping the distribution of iron in 3D using X-ray micro-computed tomography (μCT) and in 2D using energy-dispersive X-ray spectroscopy. We demonstrate a difference in tracer distribution between the wetting front and the fully saturated region supporting that imbibition proceeds in two phases, i.e. liquid percolation through the cell wall initially prior to filling of the external pore spaces. Critically, we demonstrate that these iron tracers enhance image contrast and allow for new imaging modalities in μCT for fibre networks. [Display omitted] [ABSTRACT FROM AUTHOR]

Bionanocomposites fabricated using metal nanoparticles serve a wide range of biomedical applications viz., site targeted drug delivery, imaging etc. Theranostics emerge as an important field of science, which focuses on the use of single entity for both disease diagnosis and treatment. The present work aimed at designing a multifunctional nanocomposite comprising of iron/gold hybrid nanoparticles, coated with oleyl chitosan and conjugated with methotrexate. The HR-TEM images revealed the spherical nature of the composite, while it's nontoxic and biocompatible property was proved by the MTT assay in NIH 3T3 cells and hemolysis assay. Though the VSM results exhibited the magnetic property, the MRI phantom images and X-ray contrast images demonstrated the potential of the composite to be used as contrast agent. Thus the prepared nanocomposite possess good cytocompatibility, magnetic property and also high X-ray attenuation, wherein it could serve as a novel platform for both MRI and CT diagnosis, as well as drug conjugation could aid in targeted drug delivery. [ABSTRACT FROM AUTHOR]

Activated carbon AC was treated with Kmn04 and the treated AC was used to be impregnated with iron oxide. The ratio of 0.1 M KMnO 4 treatment on AC to the 0.1 M iron sulfate precursor (0.1KMnO 4 :0.1Fe) showed the most efficient adsorbent with an adsorption capacity of 108.60 mg/g. The CO 2 adsorption isotherm at 25 °C was assessed with the adsorption isotherm model found that the Freundlich model to be the best fit which implies the multilayer adsorption onto heterogeneity surface. The adsorbent was used to perform CO 2 adsorption at 30, 40, 50 and 70 °C in which the optimum adsorption temperature was at 30 °C. The decrease in adsorption capacity with increasing temperature indicates that a physisorption process takes place. The kinetic data for CO 2 adsorption at different temperatures were well fitted to the pseudo-second-order kinetic. The adsorption was near to the chemisorption process based on the activation energy of 39.8 kJ/mol. It might be due to the weak interaction between CO 2 and AC and strong bonding between CO 2 and iron oxide. The adsorption capacity insignificantly reduced by 3.5% after four cycles showed practically efficient in CO 2 capture. [Display omitted] • A sorbent was synthesized by a ratio of KMnO 4 treated on AC towards iron oxide loading. • The most efficient adsorbent for CO 2 capture was 0.1KMnO 4 :0.1 Fe. • Freundlich model showed the best fit to the CO 2 adsorption isotherm at 25 °C. • The pseudo-second-order kinetic fit better with activation energy of 39.8 kJ/mol. [ABSTRACT FROM AUTHOR]

• An innovative galvanic cell simulated electrochemical reactions in pipe scale. • Electrochemical evidence verified the reduction of iron oxides in anoxic conditions. • Kinetics plays most important role in the reduction of iron oxide scale. • Goethite was transformed into magnetite as a result of the reduction of pipe scale. Iron release from pipe scale is an important reason for water quality deterioration in drinking water distribution systems (DWDS) globally. Disruption of pipe scale, release and transformation of iron compounds are hot topics in the field of water supply. The aim of this study is to determine whether and how ferric components in pipe scale be reduced under anoxic condition. In this study, new investigation approaches were applied, which include simplifying the complex scale into electrode pairs, developing novel simulating reactors and conducting tailored electrochemical assays. A galvanic cell reactor with anode of metallic iron (Fe0) and various cathode made of certain iron oxide (FeO x) was firstly developed to simulate the complex niche and components of pipe scale. Electrochemical methods were used to study the reduction characteristics of scale. The results proved that reduction of iron oxide scale did occur under anoxic condition. Electromotive forces between various electrodes match the Nernst Equation quite well. As main components in pipe scale, lepidocrocite (γ-FeOOH) was found to be the most reducible iron oxide but at low rate, while goethite (α-FeOOH) has weak reducibility but can be quickly reduced. As a result of electrochemical reactions, goethite in pipe scale was transformed into magnetite (Fe 3 O 4). By these means, electrochemical reaction mechanisms of pipe scale disruption were revealed, which is helpful to restrain pipe corrosion and water deterioration in DWDS. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis, characterization and biosensing application of polypyrrole enwrapped nanoparticles. • The redox active sites of Fe 2 O 3 created passage for electron transportation. • La 2 O 3 induced massive defects for DA adsorption. • PPy provided stability and enhanced electron shuttling. • These synergistic properties amplified the transduction signals leading to the higher electrocatalytic activity for DA oxidation. Dopamine (DA) disorder has been associated in pathogenesis of many neuronal dysfunction. So, DA homeostasis is the thumbprint of enduring neuronal health and physiological condition. However, the development of molecular probes that allow in vitro screening of DA with spatiotemporal resolution is a great challenge. For this purpose, we report a synthesis, characterization and application of lanthanum oxide modified iron oxide nanoparticles enwrapped polypyrrole interface (La 2 O 3 @Fe 2 O 3 /PPy). This newly integrated material has been characterized via Raman spectroscopy, Scanning electron microscopy (SEM), Zeta Potential, X-ray diffraction spectroscopy (XRD) and Atomic force microscopy (AFM). The Fe 2 O 3 created passage for electron transportation owing to presence of redox active sites, La 2 O 3 introduction induced massive defects for analyte adsorption and PPy provided stability with enhanced electron shuttling. These synergistic properties eventually amplified the transduction signals leading to the higher electrocatalytic activity for DA oxidation. The designed La 2 O 3 @Fe 2 O 3 /PPy transducing interface accomplished selective DA sensing and a detection limit was found to be 1.2 nM in the linear bounds of 100 µM to 3.5 mM. In addition, the interface was effectively utilized to detect dopamine from the lacrimal fluid with decent recoveries. We antedate that this design will pave the ways for the in vitro analysis of DA from real samples with desired selectivity and sensitivity. [ABSTRACT FROM AUTHOR]

[Display omitted] • First application of nano Fe 2 O 3 to in-situ burning of spilled oil. • Fe 2 O 3 modifies temperature profile and enhances the burning efficiency of crude oil. • Iron oxide catalytically assists crude oil oxidation via a redox mechanism. • Crude oil properties impact the effectiveness of additives during in-situ burning. Oil spills in open waters are ongoing threats to the ecosystem, especially marine life. In situ burning (ISB) has been identified as one of the practical responses to these accidents. One of the challenges in applying ISB is the lower efficiency in the burning of heavy oil fractions. This systematic study investigated the feasibility of applying commercially available, inexpensive, and non-toxic iron oxide (Fe 2 O 3) as an additive for ISB of crude oils. Our results showed that Fe 2 O 3 nanoparticles with redox properties generate ionic oxygen species (found in the vicinity of surface defects), which catalyze the combustion reaction. Furthermore, Fe 2 O 3 addition could shorten the gap between the burning of light fractions and the heavy fractions of crude oils (the difference between low-temperature oxidation (LTO) and high-temperature oxidation (HTO) decreased from 88 to 36 degrees upon addition of Fe 2 O 3) and eliminate the endothermic distillation step (involved in the burning process), which in return improved the burning of heavy fractions. This supports the use of Fe 2 O 3 nanoparticles as an effective additive to enhance ISB, especially of light crude oils. This additive resulted in an increase in the burning efficiency of light crude oil by two folds. This study shares the first application of nanoparticles in ISB, revealing its unleashed potential for further developments by the scientific community. [ABSTRACT FROM AUTHOR]

• Size effect of iron oxide NPs (NP10, NP20, NP30, and NP40) was investigated in pumpkin. • TEM and VSM analyses revealed root-to-shoot translocation of all tested NPs. • NP30 exhibits the highest translocation performance, while a negligible amount of NP10 and NP40 reached to the leaves. • The status of nutrient elements significantly altered depend on NP-type. • The findings could be important for selecting the most suitable NP size for agricultural practices. The ability of nanoparticles (NPs) to migrate in the plant body is an important issue to ensure that the NPs reach the desired tissue and to be able to select the most efficient NPs for agricultural applications. In this study, the size impact of four different iron oxide NPs (8–10, 18–20, 20–40, and 30–50 nm referred as NP10, NP20, NP30, and NP40, respectively) on their translocation in pumpkin was elucidated. To assess the root-to-shoot translocation, phloem sap was examined under transmission electron microscope (TEM). In addition, vibrating sample magnetometer (VSM) and inductively coupled plasma optical emission spectrophotometry (ICP-OES) analyses of stem and leaf tissues were performed to confirm size-dependent translocation. TEM and VSM analyses verified root-to-stem translocation of all tested NPs. The NPs treatment significantly altered the abundances of Mn, Cu, K, P, Al, Mg, and Na in tissues. The iron (Fe) content was abundant in plants treated with NP30 and NP20, and the lowest in plants treated with NP10 and NP40. Together with, only NP30 was found to be significantly translocated to the leaves, where it was 393 mg/kg in DW, about 2.3 times that of control. These findings pointed out the size-dependent translocation of NPs. It seems that biological barriers in the vascular bundle appear to restrict the migration, especially for NPs with an average size of 40 nm and above in pumpkins. These findings are important for selecting the most suitable size of iron oxide NPs for use in agricultural practices. [ABSTRACT FROM AUTHOR]

Iron oxide is intensively explored for its high capacity and abundant reserves. Suffering from poor conductivity and huge volume variation during repeating lithiation/delithiation, the capacity decays quickly. Herein, carbon coated porous iron oxide nanotubes (FeO x @C) is synthesized via hydrothermal method and subsequent annealing to achieve cycling stability. FeO x @C-2 exhibits excellent rate capability and superior cycling life. As anode material for lithium ion batteries, it delivers a high reversible capacity of 948.5 mAh g−1 at 2 A g−1 after 500 cycles. The initial coulombic efficiency is 88.7% and nearly 100% in the following cycles. The superior electrochemical performance belongs to improved electrical conductivity of carbon coating layer and exceptional stress relaxation of porous hollow structure of nanotube. • Amorphous carbon coated Fe 3 O 4 porous nanotubes (FeO x @C) was synthesized. • The hollow structure of FeO x @C facilitates the Li+ diffusion and the structure integrity. • The carbon layer boosts the conductivity and accommodates the volume variation. • FeO x @C-2 exhibits superior lithium storage performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • The fluorescent iron oxide quantum dots were prepared. • The fluorescent iron oxide quantum dots are enhanced in the presence of lysine. • Selective detection of lysine in dairy products in 2 min is achieved. In this work, a simple, easy and selective method for sensing lysine in an acidic medium was developed based on fluorescent iron oxide quantum dots (IO QDs). IO QDs using the hydrothermal method were prepared with different conditions (concentration of NPs, amount of citric acid, heating time, heating temperature, and total volume in the hydrothermal reactor) where iron oxide nanoparticles (IO NPs) were used as the starting materials. TEM, FTIR, UV–Vis Spectrometry, fluorescence spectrometry, Powder XRD, VSM were used to characterize the as-prepared IO QDs. The surface of the IO QDs contained –OH, –COO–, and other functional groups that acted as a bridge to bind the IO QDs nanoprobe with the surrounding analytes. Under acidic conditions (pH 3.0), IO QDs exhibited a rapid and interference-free fluorescence enhancement behavior after adding lysine within 2 min at room temperature, whereas other amino acids had no effect on IO QDs fluorescence. Therefore, the IO QDs prepared in this study have shown potential in lysine sensing applications. The results showed that the relative FL intensity was linear with lysine concentration in the range of 1–100 μM and had a detection limit of 0.66 μM. This proposed method has high selectivity for lysine over other amino acids, and the developed methods were used in real sample with good recoveries. Under relatively acidic conditions, a specific and fast lysine interaction was observed, resulting in the successful of IO QDs as the fluorescent probe for rapid and interference–free lysine assessment in dairy products. [ABSTRACT FROM AUTHOR]

[Display omitted] • C. papaya fruit extract-based Fe 2 O 3 NPs were synthesized and characterized. • Fe 2 O 3 NPs have shown significant antibacterial effects on Gram-negative bacteria. • Fe 2 O 3 NPs have shown H 2 O 2 radical scavenging activity. • Fe 2 O 3 NPs efficiently degraded the toxic methyl orange (MO) dye. In this work, C. papaya fruit extract coated Fe 2 O 3 NPs were green synthesized and bio-physically characterized by UV–visible spectroscopy (UV–vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Energy dispersive X-ray (EDX) techniques. In UV–vis spectroscopy, the absorbance spectra of Fe 2 O 3 NPs were recorded at 300–700 nm. A strong absorbance peak was noticed at 346 nm. XRD was employed to determine the crystalline form of NPs using powdered X-ray diffractometer. XRD reflected the pure crystalline form of NPs and the crystallite size measured 7.8 nm. The presence of various functional chemical groups in the reduction process was observed by FTIR spectroscopy from 4000 to 400 cm−1. SEM and EDX of Fe 2 O 3 NPs were performed using Hitachi S-4500 (Germany). SEM analysis revealed the presence of agglomerated NPs. The mean size of Fe 2 O 3 NPs was 23.7 nm. The presence of elemental Fe was 51.06 % and O was 28.97 % as recorded in EDX analysis. The antibacterial effects of Fe 2 O 3 NPs were evaluated against Gram-positive (B. subtilis and S. pyogenes) and Gram-negative (P. aeruginosa and E. coli) bacteria by agar well diffusion method. Dimethyl sulfoxide (DMSO) was used as negative control while tetracycline was used as positive control. Fe 2 O 3 NPs have significantly inhibited Gram-negative bacteria. The inhibition of E. coli was 20.2 mm at 100 μg mL−1. The inhibition was 17.5 mm at 100 μg mL−1 for P. aeruginosa. Fe 2 O 3 NPs exhibited radical scavenging activity against hydrogen peroxide (H 2 O 2). The percentage scavenging of H 2 O 2 was enhanced to 90 % at 100 μg mL−1. Moreover, the as synthesized Fe 2 O 3 NPs at 1 mM concentration efficiently degraded methyl orange (MO) dye and was noticed by the reduction in the absorbance peak at 375 nm within 4 h of reaction compared to 0.5 mM Fe 2 O 3 NPs. The results suggested that the synthesized Fe 2 O 3 NPs could be used to treat microbial infections and oxidative damage. Further, Fe 2 O 3 NPs may be used as a better biocatalyst for the removal of harmful industrial dyes from the environment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis and evaluation of a new potential biolubricant from castor oil. • Modified castor seed oil showed potential physiochemical properties using iron oxide as an additive. • ANN based production and optimization was successfully achieved. The study presents the production of biolubricant from castor oil using Fe 3 O 4 nanoparticles and ethylene glycol in a transesterification process, as an additive. Operational parameters such as FAME/alcohol, catalyst loading, and temperature were optimized. The reaction was complete after two hours at 160 °C, giving a yield of 94 %. To enhance the physiochemical properties of modified castor seed oil (MCSO), Fe 3 O 4 nanoparticles and ethylene glycol were used. The biolubricant yield was also predicted using artificial neural networks (ANN). The multilayer perceptron (MLP)-based ANN showed a linear correlation between the output and target values at different temperatures, the amount of catalyst, and the alcohol/FAME ratios during training, testing, and validation. The tribological properties of the biolubricant produced (MCSO + ethylene glycol + 0.5 % Fe 3 O 4 nanoparticles) showed the lowest coefficient of friction (almost 50%) and 40% decreased wear compared to raw castor seed oil and other biolubricant samples produced. [ABSTRACT FROM AUTHOR]

Iron oxide magnetic nanoparticles (MNPs) are of interest in biomedicine and research owing to their moderate cytotoxicity and advanced properties, such as extensive surface-to-volume ratio and possibilities for tailoring their functionality through surface chemistry. To date, various approaches have been used for the synthesis of MNPs with controllable structural properties and various coatings to enhance their stability and functionality. This study describes a modified one-step method of coprecipitation in the presence of glycine allowing the production of particles with controllable size and in situ surface decoration. The effect of different glycine concentrations on the morphostructural and magnetic properties of iron oxide MNPs is studied. The particle size is reduced from 10.2 ± 0.3 to 7.2 ± 0.5 nm by increasing the glycine concentration from 0.06 up to 0.60 mol. The magnetic properties of obtained particles were tracked by SQUID magnetometry and Mössbauer spectroscopy. All samples of glycine capped iron oxide MNPs showed superparamagnetic behaviour at room temperature with maximal value of the saturation magnetization of 69 ± 4 Am2/kg. The results show the optimal concentration range of glycine which can be used in this method: a lower concertation than 0.15 mol does not affect the properties of obtained particles while higher concentrations than 0.3 mol lead to the reduction of magnetic properties (the saturation magnetisation reduces to 59 ± 3 Am2/kg when glycine concentration was 0.6 mol). The proposed economic and environment-friendly approach can be utilized to synthesise –NH 2 functionalised MNPs for biomedical or wastewater treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

• Shape-Stabilized n-Heptadecane/PolyHIPE foams with Fe 3 O 4 nanoparticles were prepared. • PolyHIPE Foams were obtained via polymerization of high internal phase emulsions as frameworks. • Fe 3 O 4 nanoparticles were synthesized mechanically assisted co-precipitation method. • Polymer matrix doped with Fe 3 O 4 was used for impregnation of n-heptadecane as PCM. • Incorporation ratio and energy storage capacity were found as 67% and 99.6 J/g. This study based on design, preparation and characterization of polymerized high internal phase emulsion (poliHIPE) foams as support materials containing iron oxide (Fe 3 O 4) nanoparticles for impregnation of n-heptadecane as phase change material (PCM). The Fe 3 O 4 nanoparticles were synthesized mechanically assisted co-precipitation method and modified for harmonization with the emulsion system. Fe 3 O 4 nanoparticles doped support materials were prepared via emulsion-templated strategy, and the produced polymeric foams used for preparation of shape-stabilized n-heptadecane based composite PCMs. The total latent heat was determined as 99.6 J/g by differential scanning calorimetry (DSC) analysis, while the impregnation ratio of n-heptadecane was found to be 67%. The performances of composites were also investigated via leakage test and heat storage rate measurement. Based on the analysis result, it was determined that shape-stabilized n-heptadecane based composite PCMs are promising energy materials for low temperature latent heat storage applications. [Display omitted] [ABSTRACT FROM AUTHOR]

This study addresses the effect of fuel-to-oxidizer ratio (∅ =1.47, 1.57, 1.67, 1.77 and 1.87) on the structural, optical and dielectric properties of iron oxide nanoparticles synthesized through solution-combustion technique with glycine as the fuel. The synthesized samples were characterized using scanning electron microscopy, energy dispersive X-ray (EDX) spectroscopy, Fourier transform-infrared spectroscopy (FT-IR), ultraviolet–visible (UV-VIS) diffuse reflectance spectroscopy (DRS), X-ray powder diffraction (XRPD) with Rietveld refinement, thermogravimetric analysis (TGA) and frequency-dependent dielectric analysis. Electron micrographs show no change in morphology with respect to ∅. The EDX results revealed the existence of Fe and O. FT-IR confirmed the metal-oxygen (M − O) functional groups of iron oxides typically present near ∼ 570 and ∼ 520 cm−1. The synthesized samples showed typical reflectance spectrum of iron oxides during UV–Vis DRS analysis, where the maximum optical band gap of 1.80 eV was displayed by Fe 2 O 3 with ∅ = 1.67. The diffraction peaks were indexed with two phases: α-Fe 2 O 3 and γ-Fe 2 O 3. It was observed that the γ -phase decreased as ∅ increased. Rietveld refinement showed that ∅ = 1.47 had γ-phase as the majority (96.46 wt%), while ∅ = 1.87 had α-phase as the majority (79.90 wt%). The average crystallite size of α-phase was found to be 44.72 nm, while that of the γ -phase was 27.53 nm. The real and imaginary parts of dielectric constant, dielectric tangent loss, electric modulus, impedance and ac conductivity with respect to varying frequency were studied. All the parameters display typical trends shown by Fe-based ceramics agreeing to the Maxwell-Wagner type of interfacial polarization. The modulus studies revealed that the samples show non-Debye type relaxations and it can be concluded that these materials are well suited for high-frequency applications. • Fe 2 O 3 was prepared by solution-combustion method with varying fuel-to-oxidizer ratio (1.47–1.87). • All the prepared samples have tetragonal and rhombohedral crystal structures. • The samples exhibited low dielectric loss and good stability over the frequency range studied. • AC electrical conductivity increased with increasing frequency. [ABSTRACT FROM AUTHOR]

Enhancement of drug efficacy is essential in cancer treatment. The immune stimulator ovalbumin (Ova)-coated citric acid (AC-)-stabilized iron oxide nanoparticles (AC-IO-Ova NPs) and enhanced permeability and retention (EPR)-based tumor targeted 4.5 generation poly(amidoamine) dendrimer(4.5GDP)-cisplatin (Cis-pt) nanocomplex (NC) (4.5GDP-Cis-pt NC) were used for enhanced anticancer efficiency. The formations of 4.5GDP-Cis-pt NC, AC-IO, and AC-IO-Ova NPs were examined via FTIR spectroscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. The conjugation of Cis-pt with 4.5GDP was confirmed using carbon NMR spectroscopy. The tumor-specific 4.5GDP-Cis-pt NC provided 45%and 28% cumulative cisplatin release in 72 h at pH 6.5 and 7.4, respectively. A significant immune response with high TNF-α and IL-6 cytokine secretion was confirmed for the co-incubation of AC-IO-Ova with RAW 264.7 or HaCaT cells. AC-IO-Ova NPs were biocompatible with different cell lines, even at a high concentration (200 µg mL−1). However, AC-IO-Ova NPs mixed with 4.5GDP-Cis-pt NC (Cis-pt at 15 µg mL−1) significantly increased the cytotoxicity against the cancer cells in a dose-dependent manner with the increasing AC-IO-Ova NPs concentrations. The increased anticancer effects may be attributed to the generation of reactive oxygen species (ROS). Moreover, AC-IO-Ova NPs might assist the efficiency of anticancer cells, inducing an innate immune response via M1 macrophage polarization. We provide a novel synergistic chemoimmunotherapeutic strategy to enhance the anticancer efficacy of cisplatin via a chemotherapeutic agent 4.5GDP-Cis-pt NC and induce proinflammatory cytokines stimulating innate immunity through AC-IO-Ova NPs against tumors. [Display omitted] • Chemoimmunotherapy by ovalbumin-iron oxide and dendrimer-cisplatin against tumor. • Attacking cancer by dendrimer-cisplatin with pH response to acid microenvironments. • Ovalbumin-iron oxide can activate M1 polarization from naïve macrophage. • ROS production against tumor by iron oxide synergistic with dendrimer-cisplatin. [ABSTRACT FROM AUTHOR]

Artificially mimicking structures/morphologies available in the nature to develop multifunctional materials for catalysis is receiving greater attention. Particularly, the burdock flower morphology, which has a hollow-globe surrounded by spiky sheets, represents a multifunctional structure helpful in adsorption as well as intercalation of molecules. Given this, we have strategically developed a robust microwave (MW) bubble-template process to achieve highly uniform α-Fe 2 O 3 and carbon-enriched Fe 3 O 4 (Fe 3 O 4 @C) phases resembling the characteristics of spiky hollow burdock morphologies. The utilization of the MW bubble-templates as a pretreatment to the iron-based precursor solution helps in producing hollowed open-space ferrous glycolate burdock flower morphology with rapid production rate and without any addition of extra agents. Such burdock flower structures remain intact even after annealing in air/N 2 ambiance providing highly photoactive α-Fe 2 O 3 or magnetic Fe 3 O 4 @C, respectively. Utilizing the hollow burdock flower structures together with the individual photo/magnetic properties of iron oxide phases, a dual-layer filter was designed to remove hazardous dye molecules from water, which efficiently photodegraded (99.2 %) in natural sunlight as well as showed excellent adsorption (99.7 %) within minutes. Comparatively, a lower catalytic activity using simple iron oxide nanoparticles, closed, and faded burdock morphologies were seen. Hence, the high catalytic activity in removing the dye molecules, retention of structural phases after repeated use, and strong durability were a result of the synergetic effect of photo/magnetic properties, activated surface/spiky open burdock structure. Polymerized growth of FG nanoflakes on MW-induced glycol bubble templates.Their smooth transitions towards α-Fe 2 O 3 (photocatalyst) and Fe 3 O 4 @C (efficient adsorbent) hollowmicrourchins under suitable annealing conditions. Inset: (Right) shows structural/morphological transformation of product with concentration/MW-dose. [Display omitted] [ABSTRACT FROM AUTHOR]

We prepared two-dimensional (2D) stack-structured magnetic iron oxide (Fe 3 O 4) nanoparticle anchored titanium carbide (Ti 3 C 2 T x) MXene material (Ti 3 C 2 T x /Fe 3 O 4). It was used as a potential adsorbent to remove carcinogenic cationic dyes, such as methylene blue (MB) and rhodamine B (Rh B), from aqueous solutions. Ti 3 C 2 T x /Fe 3 O 4 exhibited maximum adsorption capacities of 153 and 86 mg g−1 for MB and Rh B dyes, respectively. Batch adsorption experimental data fits the Langmuir model well, revealing monolayer adsorption of MB and Rh B onto the adsorption sites of Ti 3 C 2 T x /Fe 3 O 4. Additionally, Ti 3 C 2 T x /Fe 3 O 4 showed rapid MB/Rh B adsorption kinetics and attained equilibrium within 45 min. Moreover, Ti 3 C 2 T x /Fe 3 O 4 demonstrated recyclability over four cycles with high stability due to the presence of magnetic Fe 3 O 4 nanoparticles. Furthermore, it exhibited remarkable selectivities of 91% and 88% in the presence of co-existing cationic and anionic dyes, respectively. Given the extraordinary adsorption capacities, Ti 3 C 2 T x /Fe 3 O 4 may be a promising material for the effective removal of cationic dyes from aqueous media. [Display omitted] • Magnetic 2D MXene material towards multiple cationic dye sequestration. • Unprecedented MB and Rh B adsorption capacities of 153 and 86 mg g−1, respectively. • Presence of Fe 3 O 4 provides excellent regeneration capability with high stability. • High selectivities of 91 % and 88 % for MB and Rh B, respectively, with rapid kinetics. • MB and Rh B removal via electrostatic attraction and hydrogen bonding with MXene. [ABSTRACT FROM AUTHOR]

• Clusters of iron oxide (Fe 3 O 4 /γ-Fe 2 O 3) nanoparticles (CIONs) are synthesized. • Stability and thermal conductivity (TC) of CION-water nanofluids are stated. • The larger the cluster size, the greater the TC increase for the nanofluids. • A maximum 4.4% TC increase is reached by the largest synthesized clusters (240 nm). • The 0.50 wt% nanofluid shows the best prospects as a heat transfer fluid. In this study, the thermal conductivity of aqueous nanofluids containing clusters of iron oxide (Fe 3 O 4 / γ - Fe 2 O 3) nanoparticles has been investigated experimentally for the first time, with the aim of assessing the role of a controlled aggregation of nanoparticles in these final nanofluids. For that, clusters of iron oxide nanoparticles of different cluster size (46–240 nm diameter range) were synthesized by a solvothermal method and fully characterized by transmission electron microscopy, X-ray diffraction and Raman spectroscopy. The rheological behavior of the optimal nanofluids was also studied by rotational rheometry. The nanofluids were obtained by dispersing the clusters of iron oxide nanoparticles in water taking into account different solid volume fractions (from 0.50 to 1.5 wt%) and the experiments were conducted in the temperature range from 293.15 K to 313.15 K. The study reveals and quantifies enhancements in the thermal conductivity of nanofluid with increase of cluster size and temperature. Furthermore, a 0.50 wt% concentration of clusters of iron oxide nanoparticles within the whole range of proposed nanofluids offers great stability and improved thermal conductivity for heat transfer applications with an small dynamic viscosity increase. In addition, the larger the size of the clusters of iron oxide nanoparticles, the greater the increase in thermal conductivity for the designed Fe 3 O 4 / γ - Fe 2 O 3 cluster-based nanofluids, with thermal conductivity values following a constant upward trend and reaching a maximum increase of 4.4% for the largest synthesized clusters (average size of 240 nm). These results open the door for the development of iron oxide - based nanofluids on which taking advantage of an optimized aggregation of nanoparticles by using size - customized clusters. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effect of As(III) and As(V) on the oxidase-like activity of CeO 2 nanoparticles revealed. • Effect of As(III) and As(V) on the peroxidase-like activity of Fe 3 O 4 nanoparticles revealed. • Adsorption of inorganic arsenic species measured by isothermal titration calorimetry. Nanoparticles are massively discharged into the aquatic environment leading to adverse health effects. Considering their adsorption of small molecules and polymers, it is important to study the effect of aqueous system composition on NPs' behavior and toxicity. Nanomaterials with enzyme-like activities have caught a lot of recent research interest. Since nanozyme reactions take place on the surface of nanomaterials, their catalytic activities often show significant influence by adsorption of small molecules and polymers. CeO 2 and Fe 3 O 4 nanoparticles are two classic nanozymes, showing oxidase and peroxidase like activities, respectively. Inorganic arsenic species are critical for environmental and catalytic research. In this study, we used 3,3′,5,5′-tetramethylbenzidine (TMB) as a model substrate to examine the effect of inorganic arsenic species (As(III) and As(V)) on the activity of CeO 2 and Fe 3 O 4. The oxidation capacity of nanoceria was decreased to one third with the addition of 1 mM As(III), but was improved by 3-fold in the presence of 0.1 mM As(V). The former is mainly due to the reducing power of As(III), while the latter is attributable to the adsorption of As(V) on the nanoceria surface decreasing the electrostatic repulsion between nanoceria and TMB. For Fe 3 O 4 , its activity was first promoted and later inhibited by both As(III) and As(V). Therefore, nanomaterials not only affect arsenic species through redox chemistry and adsorption, but in turn arsenic can affect the catalytic activity of nanomaterials. [ABSTRACT FROM AUTHOR]

In this study, modular two-in-one nano-cocktails were synthesised to provide treatment of inflammatory diseases and also enable tracking of their delivery to the disease sites. Chitosan nano-cocktails loaded with treatment module (cerium oxide nanoparticles) and imaging module (iron oxide nanoparticles) were synthesised by electrostatic self-assembly (Chit-IOCO) and ionic gelation method (Chit-TPP-IOCO), respectively. Their MRI capability, anti-inflammatory and anti-fibrosis ability were investigated. Results demonstrated that Chit-IOCO significantly reduced the expression of TNF-α and COX-2, while Chit-TPP-IOCO reduced IL-6 in the LPS-stimulated macrophages RAW264.7. Cytotoxicity studies showed that the nano-cocktails inhibited the proliferation of macrophages. Additionally, Chit-IOCO exhibited higher in vitro MRI relaxivity than Chit-TPP-IOCO, indicating that Chit-IOCO is a better MRI contrast agent in macrophages. It was possible to track the delivery of Chit-IOCO to the inflamed livers of CCl 4 -treated C57BL/6 mice, demonstrated by a shortened T 2 ⁎ relaxation time of the livers after injecting Chit-IOCO into mice. In vivo anti-inflammatory and blood tests demonstrated that Chit-IOCO reduced inflammation-related proteins (TNF-a, iNOS and Cox-2) and bilirubin in CCl 4 treated C57BL/6. Histology images indicated that the nano-cocktails at the treatment doses did not affect the organs of the mice. Importantly, the nano-cocktail reduced fibrosis of CCl 4 -treated mouse liver. This is the first reported data on the anti-inflammation and anti-fibrosis efficacy of Chit-IOCO in C57BL/6 mouse liver inflammation model. Overall, Chit-IOCO nanoparticles have shown great potential in MR imaging/detecting and treating/therapeutic capabilities for inflammatory diseases. [Display omitted] • Multipurpose nano-cocktails (NCs) incorporating both treatment and MR imaging modules • NCs demonstrated exceptional reduction in mouse liver inflammation and fibrosis. • NCs displayed distinct MRI signal in mouse liver, allowing tracking of material. [ABSTRACT FROM AUTHOR]

Because of the low cost and environmental friendliness, iron oxide is widely applied in various application fields. Iron oxide is also considered as a promising anode material for lithium ion batteries, but it usually exhibits poor electrochemical properties because of its poor conductivity and large volume variation during the lithium uptake and release. To address this issue, a three-dimensional (3D) structure was developed, in which Fe 3 O 4 nanorods were selectively supported on carbon nanotubes (CNTs) and subsequently coated by graphene (CNTs-Fe 3 O 4 @graphene). Due to the strong interaction within graphene, CNT and Fe 3 O 4 nanorod as well as high conductivity of CNT, the resulting CNTs-Fe 3 O 4 @graphene nanocomposites exhibited enhanced cycling performance and rate capability in comparison with Fe 3 O 4 @graphene composite, especially improved reversible capacity in the first cycle. The present investigation provides insights into the design of nanostructures for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

• Iron oxide nanoparticle in-situ decorated boron nitride nanosheet (FeBN) was successfully fabricated via sol–gel method. • FeBN was uniformly dispersed in ALSR matrix. • FeBN significantly improved the thermal stability and flame retardancy of ALSR. To promote the application of silicone rubber in the electronics industry, it is urgent to improve its thermal stability and flame retardancy. In this work, iron oxide nanoparticle in-situ decorated boron nitride nanosheet (FeBN) was fabricated via sol–gel method and then incorporated into addition-cure liquid silicone rubber (ALSR). It was found that FeBN uniformly dispersed in polymer and effectively improved the thermal stability and flame retardancy of ALSR. With only 2.0 phr FeBN, the T 10 and LOI of ALSR were increased to 438.2 °C and 28.5%, respectively, which was attributed to the synergism of free-radical quenching capability and layer barrier effect. [ABSTRACT FROM AUTHOR]

Hybrid nanocomposites of bacterial cellulose (BC) and magnetic iron oxide nanoparticles (NPs) are of interest due to their potential for novel applications. Magnetic NPs are typically synthesized by co-precipitation since it is facile, enabling control of their size and distribution. This work investigates the effect of using different starting reactants (Fe(II) and Fe(III) salts) in the fabrication and control of the properties of BC/iron oxide nanocomposites. It was found that the choices of starting reactants are not important for synthesizing NPs outside of the BC networks. However, the starting reactants do affect the formation of NPs when they are synthesized in the BC network. Significant differences in the morphologies, sizes, crystal structures, and magnetic phases of NPs occurs when in this environment. The nanopores of BC networks in some instances force the aggregation of the NPs, either within the pores, or on the surfaces of the fibrils. Nanocomposites synthesized from Fe(II) sulfate and Fe(III) chloride were found to exhibit the highest magnetization. These nanocomposites have potential for flexible sensors, actuators, or electromagnetic shielding. Nanocomposites from Fe(II) acetate and Fe(III) chloride, though exhibiting lower magnetization, preserve a porous structure. Thus, they have potential as adsorbents or for wound healing applications. Unlabelled Image • The starting reactants are not important for the characteristics and properties of the Fe 3 O 4 NPs without BC. • When NPs are formed inside BC networks, the starting materials influence the nanocomposites characteristics and properties. • Morphology, size, crystal structure, loading amount, and magnetic phase of Fe 3 O 4 NPs are affected by the BC networks. • The ability to alter and control the properties of the NPs enables one to direct towards specific target applications. [ABSTRACT FROM AUTHOR]

Mesoporous silica nanoparticles with a superparamagnetic iron oxide core were prepared in this work, in order to obtain multifunctional platforms with adequate features for cancer theranostics. Three different core-shell nanocomplexes were obtained: IO-OAm/mSiO 2 , IO-APTES/mSiO 2 and IO/SiO 2 /mSiO 2. In the case of IO-OAm/mSiO 2 and IO-APTES/mSiO 2 , iron oxide (IO) was obtained by thermal decomposition, having in this case a coating of oleylamine (OAm) that was in the second formulation exchanged by (3-aminopropyl)triethoxysilane ligand (APTES). Regarding the IO/SiO 2 /mSiO 2 formulation, iron oxide was synthesized by microemulsion. The mesoporous silica shell (mSiO 2) on the IO nanoparticles was obtained by sol-gel and the final materials were dried by supercritical fluids drying. VSM confirmed the superparamagnetic behaviour of the nanoparticles, leading to M S of 4.0, 1.8 and 10.2 emu·g−1, for IO-OAm/mSiO 2 , IO-APTES/mSiO 2 and IO/SiO 2 /mSiO 2 , respectively. NMR relaxometry has shown the potential of these nanoparticles to be used as T 2 contrast agents, with r 2 values as high as 63.93 s−1·mM−1 Fe. The three types of nanoparticles exhibited loading contents of epirubicin of ~3% and drug release percentages of 19% for IO-OAm/mSiO 2 , 24% for IO-APTES/mSiO 2 and 31% for IO/SiO 2 /mSiO 2. The cytotoxicity of drug-loaded and non-loaded most promising nanoparticles was assessed, showing high potential of these platforms for application as anticancer drug carriers. Unlabelled Image • Superparamagnetic iron oxide/mesoporous SiO 2 core-shell nanoparticles are prepared. • New ligand exchange and supercritical fluids drying approaches were applied. • Higher % of released epirubicin compared to the literature: up to 30% after 48 h • Potential as T 2 contrast agents for MRI, with r 2 as high as 63.93 s−1·mM−1 Fe. • Promising biocompatible multifunctional platforms for cancer theranostics [ABSTRACT FROM AUTHOR]

• Photothermal boiling of an aqueous suspension of iron oxide was studied. • The addition of particles increases the evaporation efficiency of water. • Evaporation efficiency increased by at least 12% at 3 wt% particle concentration. • The model predicting steam flowrate and optimal particle concentration was developed. • The process was established in-situ using a solar concentrator. Photo-thermal evaporation of nanofluids has potential applications in solar desalination, micro-CHP (combined heat and power) and domestic off-grid disinfection. In this research, we reproduced the process experimentally using 110-nm iron oxide particles dispersed in water. At an initial lab-scale stage, under the artificial radiation of 6.9 suns, we observed that the boiling nanofluid destabilizes to a suspension of 6µm agglomerates of nanoparticles and that up to 30% of the particles escape the system with the steam. At the prototype stage, we boiled the fluid in a solar concentrator producing 35 g/min steam with an efficiency of around 60%, which is sufficient to drive a small turbine. The optimum concentration of the nanoparticles was 3 wt%. To supplement the experiments, we developed a simplified model for engineering calculations of the solar steam generation rate. The model corresponds well to the experiments deviating by only 8%. [ABSTRACT FROM AUTHOR]

• Mentha pulegium L. leaves extract reacts with ferric chloride to synthesize iron oxide NPs. • Iron Oxide NPs were greenly synthesized. • Optical and structural parameters of iron oxide product are investigated. • Iron Oxide NPs depend on ferric chloride concentration in the extract. In this study, green synthesis of iron oxide nanoparticles was successfully prepared from Mentha pulegium L. leaves extract. The effect of different ferric chloride concentrations on the nanoparticles' iron oxide formation was studied. The obtained nanoparticles were characterized by UV-Vis, FT-IR, XRD, SEM and EDAX techniques are used for this purpose. UV-Vis spectra showed maximum absorption at range 275–301 nm related to the iron oxide. FTIR spectra exhibit a two weak peak at 510 and 594 cm−1 attributed to iron oxide NPs vibration, confirming the formation nanoparticles XRD confirmed the crystalline nature of Fe 3 O 4 and α-Fe 2 O 3 NPs with average size ranged in 22–34 nm. SEM showed that the green synthesizing Iron oxide nanoparticles having in general as cubical shape. As a result, the use of Mentha pulegium L. leaves extract offers its ease, fast, low cost and friendly to the environment compared to other methods. [ABSTRACT FROM AUTHOR]

We studied the formation of self-ordered nanopores in the anodization of iron foils. Different anodization conditions (e.g. water content and applied voltage) were tested, and anodization curves were obtained for each case to establish the optimal parameters for fabricating homogeneous nanoporous films. Samples were characterized by Raman spectroscopy, X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and high-resolution scanning transmission electron microscopy. Moreover, the bandgap of 2.1 ± 0.1 eV was measured in nanostructured films, and electrochemical impedance spectroscopy measurements were taken at each step. Finally, we propose a mechanism for the formation of iron oxide by anodization that takes into account the chemical reactions involved. Image 1 [ABSTRACT FROM AUTHOR]

This study describes the preparation, and evaluates the biocompatibility, of hydroxylated multi-walled carbon nanotubes (fCNTs) functionalized with magnetic iron oxide nanoparticles (IONs) creating hybrid nanoparticles. These nanoparticles were used for preparing a composite porous poly(ε-caprolactone) scaffolds for potential utilization in regenerative medicine. Hybrid fCNT/ION nanoparticles were prepared in two mass ratios - 1:1 (H1) and 1:4 (H4). PCL scaffolds were prepared with various concentrations of the nanoparticles with fixed mass either of the whole nanoparticle hybrid or only of the fCNTs. The hybrid particles were evaluated in terms of morphology, composition and magnetic properties. The cytotoxicity of the hybrid nanoparticles and the pure fCNTs was assessed by exposing the SAOS-2 human cell line to colloids with a concentration range from 0.01 to 1 mg/ml. The results indicate a gradual increase in the cytotoxicity effect with increasing concentration. At low concentrations, interestingly, SAOS-2 metabolic activity was stimulated by the presence of IONs. The PCL scaffolds were characterized in terms of the scaffold architecture, the dispersion of the nanoparticles within the polymer matrix, and subsequently in terms of their thermal, mechanical and magnetic properties. A higher ION content was associated with the presence of larger agglomerates of particles. With exception of the scaffold with the highest content of the H4 nanoparticle hybrid, all composites were superparamagnetic. In vitro tests indicate that both components of the hybrid nanoparticles may have a positive impact on the behavior of SAOS-2 cells cultivated on the PCL composite scaffolds. The presence of fCNTs up to 1 wt% improved the cell attachment to the scaffolds, and a content of IONs below 1 wt% increased the cell metabolic activity. • PCL scaffolds with the content of hybrid fCNT/ION nanoparticles under 5 wt. % expressed superparamagnetic properties. • Presence of fCNTs in PCL scaffold improves the cell adhesion. • Presence of IONs improves cell metabolic activity. [ABSTRACT FROM AUTHOR]

• Palm shell extract capped iron oxide nanoparticles chitosan (CIO) Synthesis. • CIO bionanocomposite exhibited fenton like degradation. • Fast degradation of individual and binary mixture of cationic and anionic dyes. Heterogeneous regenerative iron oxide nanocatalyst capped with palm shell extract(IO) and IO modified with chitosan has been developed by simple coprecipitation of ferrous and ferric salts for degradation of single and binary mixture of dyes in aqueous phase. The iron oxide nanoparticles were characterized using IR, UV, TEM, XRD, Raman, VSM and Mossbauer techniques. The obtained results suggest the presence of Fe 3 O 4 , γ-Fe 2 O 3 and α-Fe 2 O 3 in IO and CIO though to different extents. The degradation process was carried out at room temperature and at near neutral pH which led to complete degradation and multicyclic use of the nanocatalyst for environmental applications without loss in efficiency. CIO was observed to be more efficient as compared to IO during catalytic degradation of binary mixture of dyes. [ABSTRACT FROM AUTHOR]