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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]

[Display omitted] • α-Fe 2 O 3 was evaluated as anode of solid-state batteries using oxide electrolyte. • Smaller Fe 2 O 3 particles showed better anode performance. • Contact area between Fe 2 O 3 and the electrolyte was increased to improve performance. • Fe 2 O 3 anode operated for the first time in oxide-based solid-state Li batteries. As Li-ion battery anode materials, two types of hematite (Fe 2 O 3 (big), Fe 2 O 3 (ultrafine)) were evaluated by using liquid electrolyte and oxide-based solid electrolyte. Although the anode using Fe 2 O 3 (ultrafine) with larger specific surface area showed a high initial reversible capacity in the liquid-electrolyte cell, there was a steep capacity decay in the cycling test. In the solid-electrolyte cell, we obtained very low reversible capacities of 40 mA h g−1 for the anode using Fe 2 O 3 (big) with smaller specific surface area. In contrast, the capacity of Fe 2 O 3 (ultrafine) anode was as high as 400 mA h g−1 at the 20th cycle. This is the first demonstration of charge–discharge reactions for Fe 2 O 3 anode in oxide-based solid-state batteries. The Fe 2 O 3 (ultrafine) particles were dispersed relatively uniformly between solid electrolyte in the active layer, suggesting that the contact area between Fe 2 O 3 and solid electrolyte becomes large. Consequently, Fe 2 O 3 (ultrafine) could benefit from larger contact area delivering the suitable reaction site for Li+ to improve the anode performance. [ABSTRACT FROM AUTHOR]

The catalytic performance of modified hydroxyapatite nanoparticles, Ca 10-x Fe x-y W y (PO 4) 6 (OH) 2 , was applied for the degradation of methylene blue (MB), fast green FCF (FG) and norfloxacin (NOR). XPS analysis pointed to the successful partial replacement of Ca by Fe. Under photo-electro-Fenton process, the catalyst Ca 4 FeII 1·92 W 0·08 FeIII 4 (PO 4) 6 (OH) 2 was combined with UVC radiation and electrogenerated H 2 O 2 in a Printex L6 carbon-based gas diffusion electrode. The application of only 10 mA cm−2 resulted in 100% discoloration of MB and FG dyes in 50 min of treatment at pH 2.5, 7.0 and 9.0. The proposed treatment mechanism yielded maximum TOC removal of ∼80% and high mineralization current efficiency of ∼64%. Complete degradation of NOR was obtained in 40 min, and high mineralization of ∼86% was recorded after 240 min of treatment. Responses obtained from LC-ESI-MS/MS are in line with the theoretical Fukui indices and the ECOSAR data. The study enabled us to predict the main degradation route and the acute and chronic toxicity of the by-products formed during the contaminants degradation. [Display omitted] • New modified hydroxyapatite nanoparticles as catalysts to produce.●OH in the MB, FG dyes and NOR degradation; • High recyclability of the heterogeneous catalyst was verified due to magnetic properties. • MB, FG dyes and NOR reached high degradation rate by Photo-Electro-Fenton process using GDE. • Acute and chronic theoretical toxicological was evaluated to NOR. • The by-product identification study resulted in low toxicity compounds. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanocomposites based on graphene nanoribbons and iron oxide nanoparticles were synthesized by varying the particle size. • Properties such as specific surface area, magnetic response and specific capacitance were investigated as a function of the particle size. • All the properties studied were strongly affected by the particle size. • Nanocomposites with a high specific surface area can be obtained by tuning the particle size. • The specific capacitance of the nanocomposites is increased with the specific surface area. The particle size effect on nanocomposites made of reduced graphene nanoribbons (GNRs) and iron oxide nanoparticles (IONPs) is studied. Three nanocomposites with different particle size were prepared by chemical reduction of IONPs formed by the co-precipitation method on graphene oxide nanoribbons. Several experimental techniques such as transmission electron microscopy, selected area electron diffraction and X-ray diffraction determined the particle size distribution and crystalline phases present in the samples. The specific surface area (SSA) of the nanocomposites was measured and discussed with the mean size of the IONPs. Depending on the mean size and surface distribution of the IONPs, samples with high SSA can be achieved. Magnetic measurements indicated that the particle size affects the magnetic properties of the nanocomposites. These results were discussed considering the effect of particle size, defects, amount of particles and interaction between the IONPs and GNRs surface. The potential application of the samples as supercapacitors was evaluated by calculating their specific capacitance from cyclic voltammetry measurements. The results showed that the specific capacitance increases with the SSA. This work confirms that the size of the IONPs significantly affects the properties of the nanocomposites, specifically the SSA, which is of great interest for various applications. [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]

Iron oxide-based adsorbents showed potential to reach ultra-low phosphorus (P) concentrations to prevent eutrophication and recover P. High affinity, high capacity at low P concentrations (<1 mg L−1), good stability, and reusability of the adsorbent are key factors for economic viability. In this study, nanoparticles of goethite (α-FeOOH), a highly stable phase, have been synthesized with increasing Zn2+-doping, 0–20 %at. Zn/Fe, to manipulate the surface properties, following the results of a previous work. Mössbauer spectroscopy showed preserved goethite phase and increased point of zero charge (pzc) at low Zn-doping percentages, while at higher percentages (>5%at.) co-existing phases with increased specific surface area formed. Low concentrations (0.1–10 mg L−1) batch adsorption tests showed increased P removal per unit mass with increasing doping. However, the highest pzc, affinity and P removal per unit area were observed for the 5%at. doped sample, suggesting this dopant concentration to provide the most effective surface. A regeneration test, performed at a lower pH than usual, showed preserved, even improved P desorption with increasing doping. Mössbauer spectroscopy showed that the nanoparticle phase and composition, up to 5%at., doping was preserved throughout the process. These results are promising to develop a stable effective Zn-doped goethite-based adsorbent for P recovery at ultra-low concentrations. [Display omitted] [ABSTRACT FROM AUTHOR]

Hybrid polyion complexes (HPICs) obtained from the complexation in aqueous solution of a double hydrophilic block copolymers and metal ions can act as efficient precursors for the controlled synthesis of hybrid nanoparticles. Hence, HPICs based on a mixture of ferrous and ferric ions with poly(ethylene oxide)-block-poly(acrylic acid) were used to initiate, after the addition at 70 °C of a solution of NH 4 OH, the formation of iron oxide nanoparticles. The careful choice of the molar ratio between polymer and metal ions within HPICs enables to tune the morphology and size of the obtained iron oxide nanoparticles while maintaining the same surface composition. This control of size and composition was further used to highlight the relationship between the size of these particles and their catalytic and magnetic properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Enzyme immobilization can increase enzyme reusability to reduce cost of industrial production. Ginkgo biloba leaf extract is commonly used for medical purposes, but it contains ginkgolic acid, which has negative effects on human health. Here, we report a novel approach to solve the problem by degrading the ginkgolic acid with immobilized-laccase, where core/shell composite nanoparticles prepared by coaxial electrospraying might be first applied to enzyme immobilization. The core/shell Fe 3 O 4 /nylon 6,6 composite nanoparticles (FNCNs) were prepared using one-step coaxial electrospraying and can be simply recovered by magnetic force. The glutaraldehyde-treated FNCNs (FNGCNs) were used to immobilize laccase. As a result, thermal stability of the free laccase was significantly improved in the range of 60–90 °C after immobilization. The laccase-immobilized FNGCNs (L-FNGCNs) were applied to degrade the ginkgolic acids, and the rate constants (k) and times (τ 50) were ~0.02 min−1 and lower than 39 min, respectively, showing good catalytic performance. Furthermore, the L-FNGCNs exhibited a relative activity higher than 0.5 after being stored for 21 days or reused for 5 cycles, showing good storage stability and reusability. Therefore, the FNGCNs carrier was a promising enzyme immobilization system and its further development and applications were of interest. Unlabelled Image • Fe 3 O 4 /nylon composite nanoparticles (FNCNs) were prepared by coaxial electrospraying. • The core/shell FNCNs can be simply recovered by magnetic force. • Laccase immobilization was carried out by the glutaraldehyde-treated FNCNs (FNGCNs). • Degradation of ginkgolic acids was achieved by the laccase-immobilized FNGCNs. • The laccase-immobilized FNGCNs showed good storage ability and reusability. [ABSTRACT FROM AUTHOR]

A novel cyclic molecular designed dispersion (CMDD) method was employed to uniformly deposit 0.0–6.5 wt% Fe on CeO 2. The gold catalysts (0.0–3.8 wt%) supported on Fe 2 O 3 -CeO 2 were tested for CO preferential oxidation (PROX). As the CMDD method involved grafting of Fe (acac) 3 onto the surface –OH groups, 2.7 surface –OH/nm2 was determined for the CeO 2 by using the Grignard reagent. The performance of CMDD catalysts was compared with the corresponding catalysts prepared by impregnation. The catalysts were characterized by XPS, XRD, TPR, HRTEM-EDX, BET and ICP. The results suggested that Au/Fe 2 O 3 -CeO 2 was significantly more active and selective than Au/CeO 2. The CMDD-prepared catalysts with 1.4–2.5 wt% iron showed the highest activity and selectivity, especially at temperatures as low as 323 K. The formation of Ce-Fe solid solution for CMDD catalysts promoted the dispersion of both iron and gold. Highly dispersed gold nanoparticles mainly as small as 2.2 nm were observed in HRTEM. Image 1 • Cyclic molecular designed dispersion (CMDD) method was used to graft Fe 2 O 3 on CeO 2. • CMDD of Fe 2 O 3 enhanced iron dispersion and its interaction with Au and CeO 2. • CMDD PROX catalysts are more active and selective than impregnation ones. • An Au/Fe ratio of about 0.4 on CeO 2 reduces complete oxidation of CO to 318 K. • Highly dispersed nanosized gold particles with diameter of 1–3 nm were achieved. [ABSTRACT FROM AUTHOR]

Inorganic nanoparticles provide multipurpose platforms for a broad range of delivery applications. Intrinsic nanoscopic properties provide access to unique magnetic and optical properties. Equally importantly, the structural and functional diversity of gold, silica, iron oxide, and lanthanide-based nanocarriers provide unrivalled control of nanostructural properties for effective transport of therapeutic cargos, overcoming biobarriers on the cellular and organismal level. Taken together, inorganic nanoparticles provide a key addition to the arsenal of delivery vectors for fighting disease and improving human health. Unlabelled Image [ABSTRACT FROM AUTHOR]

In this work, PdFe 2 O 3 bimetallic materials containing oxygen vacancies (O v , from 10 to 75%) and two bimetallic nanoparticles based on noble metals (PdAu and PdPt) were obtained and evaluated for the ethanol electro‒oxidation reaction (EOR) in alkaline medium. For this purpose, bimetallic nanoparticles were synthesized keeping similar crystallite sizes (~6 nm), particle sizes (~6 nm), mass compositions (18 ± 4% co‒metal) and metallic loadings (18.3 ± 5.1%). PdAu/C, PdPt/C and the most active PdFe 2 O 3 /C material (75% of O v) displayed an improved onset potential (E onset) during the oxidation of 1.5 M ethanol in 0.3 M KOH in comparison with a monometallic Pd/C material, finding the trend: PdAu/C (−0.56 V vs. NHE) > PdPt/C (−0.55 V) > PdFe 2 O 3 /C (−0.51 V) > Pd/C (−0.50 V). In addition, these bimetallic materials presented an increase in the current density; being PdPt/C and PdFe 2 O 3 /C the most active materials for EOR. A spectroelectrochemical analysis was performed by coupling a μRaman spectroscope with an electrochemical cell. This analysis allowed to conclude that the improvement of the E onset is related to changes in chemisorption energies as was suggested by Raman shifts found for the C 1 ‒M (metal) bond, while the high activity of PdPt/C can be attributed to a higher adsorption of ethanol molecules. Additionally, it was found that the activity of PdFe 2 O 3 /C is associated with an energy decrease to form the C 1 ‒M bond, which could be promoted by the abundance of oxygen vacancies. PdFe 2 O 3 and two bimetallic nanoparticles based on noble metals (PdAu and PdPt) were synthesized and tested for ethanol electro-oxidation. The presence of oxygen vacancies in PdFe 2 O 3 improved the activity displaying similar mass activity than PdPt and higher than PdAu. Spectroelectrochemical tests revealed that the improved activity was related to changes in chemisorption energies due to shifts found for the C 1 ‒M (metal) bond. Image 1 • PdFe 2 O 3 , PdAu and PdPt with similar particle size (6 nm) and loading were obtained. • Improvements on E onset were found to be related to changes in C 1 ‒M (metal) bond. • PdFe 2 O 3 displayed higher activity than PdAu and similar activity than PdPt. • The improved activity of PdFe 2 O 3 was related to the presence of oxygen vacancies. [ABSTRACT FROM AUTHOR]

• A multiscale modeling framework for fluidized bed reactors is presented. • Chemical looping reforming reactor employing iron oxide nanoparticles is modelled. • Kinetic Monte Carlo simulations provide rates of surface chemistry. • Intra-particle transport model handles competing diffusion and chemical reactions. • Reactive multiphase flow is modeled by fluid-particle flow model. A multiscale modeling framework is described and applied to the reactivity of iron oxide nanoparticles in a chemical looping reforming (CLR) reactor. At the atomic scale/nanoscale, we have performed kinetic Monte Carlo modeling, guided by Density Functional Theory calculations, on the detailed kinetics of the CH 4 conversion to products as a function of temperature. These results have been post-processed for use in macroscopic models with the goal to integrate process information with materials information. Two levels of macroscopic models have been used to evaluate the performance of the nanoparticles in their final application: (1) a pore-unresolved intra-particle transport model that accounts for limitations via an effective diffusivity and an effectiveness factor, and (2) a fluid-particle multiphase flow model that allows the study of the consequences of clustering and intra-particle transport on overall reactor performance. This modeling approach ultimately leads to better descriptors of material performance that can be used in future materials screening activities. [ABSTRACT FROM AUTHOR]

• Iron oxide nanoparticles recovered from the acid mine drainage treatment are suitable to produce nanofluids. • Iron oxide nanoparticles in concentration 0.10–0.75 wt% can be used to produce stable nanofluids. • Additional 7–10% oil recovery is achieved after flooding due to injection of iron oxide-based nanofluids. Oil is one of the most intensively used energy sources in the world and, as a fossil fuel, it is a finite resource. Different methods have been explored to increase oil recovery from mature fields, particularly using enhanced oil recovery (EOR) with the help of nanofluids. This study performed EOR tests using iron oxide nanoparticles added to brine and sodium dodecyl sulfate solutions. Three types of iron oxide nanoparticles were examined: commercial (IO), derived from the acid drainage of an underground coal mine (SIO), and temperature-sensitive functionalized (TSIO). The nanoparticles were well characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, high-resolution X-ray photoelectron spectroscopy, and transmission electron microscopy. The nanofluids were evaluated through dynamic light scattering measurements and determination of the viscosity, turbidity, contact angle and surface tension. There was not significant variation in the surface tension of the samples, which ranged between 25.46 and 28.28 mN m−1. However, the contact angle exhibited notable fluctuations depending on the nanoparticles concentration, ranging from 7.39° to 24.43°. Furthermore, the zeta potential suggests that the stability of the nanofluid samples falls within the moderate to medium range. An improvement in oil recovery reached 10% with the commercial nanoparticles (0.50 wt%), followed by 8.5% using the synthesized (0.25 wt%) and 7.5% using the functionalized (0.25 wt%). Moreover, all nanofluids showed good stability for up to 30 days, and their viscosity showed a direct relationship with the enhancement in oil recovery. [ABSTRACT FROM AUTHOR]

Low dimension materials (especially antiferromagnetic nanoparticles) exhibit extraordinary magnetic properties, which are different from their bulk counterparts. Herein we report the synthesis of akaganeite nano-sticks by two different reaction pathways that enable good control on microstructure and surface properties, ensuring new application opportunities. Akaganeite nano-sticks prepared via conventional method have a length of 1.8 ± 0.15 µm and a diameter of 100 ± 20 nm with a smooth surface. Whereas modified method results in the synthesis of akaganeite nano-sticks with nanorods grown on their surface. Akaganeite nano-sticks produced by modified method have a length and diameter of 2.06 ± 0.02 µm and 160.26 ± 8.08 nm respectively. Ferromagnetism and near room temperature exchange biasing (250 K) was found in both the samples. The conventional method (AKN-0) demonstrates exchange biasing of 5700 A/m at 50 K whereas the modified method (AKN-2.5) shows 66275 A/m (approximately 11 times increased). XPS reveals defects generation in both methods, which results in the existence and enhancement of such magnetic properties. • Nanoscale antiferromagnetic materials shows different properties from their bulk counterpart. • Forced hydrolysis was used to synthesize 1-D β-FeOOH nanoparticles using two different synthesis routes. • Near room temperature exchange biasing and weak ferromagnetic effect was observed in antiferromagnetic akaganeite. • A correlation between defects generation and exchange biasing was developed and understood. [ABSTRACT FROM AUTHOR]

[Display omitted] • T. indica fruit extract-based Fe 2 O 3 NPs (T. indica -Fe 2 O 3 NPs) were synthesized and characterized. • T. indica -Fe 2 O 3 NPs have shown significant antibacterial effects. • T. indica -Fe 2 O 3 NPs have shown significant antibiofilm effects. • T. indica -Fe 2 O 3 NPs have shown DPPH radical scavenging activity. In this investigation, T. indica fruit extract was used to phyto-synthesize T. indica -Fe 2 O 3 NPs and then they were characterized by bio-physical techniques. The formation of T. indica -Fe 2 O 3 NPs was checked by the development of black colour precipitate. A sharp peak was noticed at 400 nm for T. indica -Fe 2 O 3 NPs by UV–Vis spectroscopy. The different XRD peaks denotes the hexagonal shape of T. indica -Fe 2 O 3 NPs and the size of crystallite was 19.8 nm. The role of phytochemicals in the plant extract during NPs synthesis was confirmed by FTIR spectra. The existence of polyhedral shaped NPs measuring 28 nm was noticed through SEM analysis. EDX spectra recorded the weight (%) of elemental iron was 77.91%. The agar well diffusion assay revealed that the prepared T. indica -Fe 2 O 3 NPs showed greater inhibition of E. faecalis and S. aureus (Gram-positive) than K. pneumoniae and E. coli (Gram-negative) at 25 to 100 µg mL−1. Biofilm inhibition of test bacteria and fungi was noted. DPPH scavenging was increased to 71.1% at 100 μg mL−1. This investigation arrives the fact that T. indica -Fe 2 O 3 NPs has the potential to treat bacterial infections and could be employed as a substitute to conventional therapeutic agent in biomedical sector in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] Spray solution combustion synthesis is proposed as a onestep method for preparation of nanostructured iron oxide–silver patchy particles for polyfunctional applications. [ABSTRACT FROM AUTHOR]

Disk-like α -Fe 2 O 3 hierarchical nanoparticles with diameters of 150–200 nm and a [1 1 0] preferred orientation have been prepared by a novel one-step method. The viscosity of the Shengli extra heavy oil reduced substantially through the combination of the α -Fe 2 O 3 nanoparticles and a hydrogen donor, which can be attributed to the changes in the oils' compositions after the catalytically pyrolytic reactions. • Disk-like α -Fe 2 O 3 nanoparticles with ca. 200 nm were prepared via a facile method. • The nanoparticles have a hematite structure with [1 1 0] preferred orientation. • The α -Fe 2 O 3 particles were used as the catalyst for the upgrading of heavy crude oil. • Combination of the nanoparticles and tetralin cause substantial viscosity reduction. • The changes in the oils' compositions account for the variations of the viscosities. In this paper, disk-like α -Fe 2 O 3 nanoparticles were synthesized by one-step via an n-octyl alcohol-mediated self-assembly process and were subsequently used as the catalyst for the updating of heavy crude oil. The characterization results show that the diameter of the as-prepared α -Fe 2 O 3 disks is in the range of 150–200 nm and the nanoparticles have a hematite structure with [1 1 0] preferred orientation. The catalyst strongly acts on the asphaltene and causes its lower S content and N content, lower aromaticity and aromatic condensation, and higher branchiness index. Adding tetralin causes the increment of aromatics content, the decrease of resin, and more molecules containing aromatic moieties bearing 2 and 3 rings. The viscosity of the Shengli extra heavy oil reduced substantially from 161180 mPa∙s to 45882 mPa∙s (50 °C) through the combination of the α -Fe 2 O 3 nanoparticles and tetralin (a hydrogen donor). [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Highly active and selective composite photocatalysts were developed for NO x abatement under visible-light illumination. • Structure of mesoporous graphitic (mpg) C 3 N 4 was synthetically fine-tuned for optimum photocatalytic performance. • Photocatalytic NO x abatement activity, selectivity and reusability of C 3 N 4 was further improved by Fe 3 O 4 -NP incorporation. • Fe2+/Fe3+ species increased oxygen reduction capacity of C 3 N 4 resulting in lower NO 2 production and higher selectivity. • Fe 3 O 4 /C 3 N 4 photocatalyst had a positive DeNOx index, making it a viable DeNOx photocatalyst under VIS light at RT. Abstract Several mesoporous graphitic carbon nitride (mpg -C 3 N 4) photocatalysts were synthesized by using a hard-templating method comprising thermal polycondensation of guanidine hydrochloride over silica spheres at three different temperatures (450, 500 and 550 ℃). After structural characterization of these mpg -C 3 N 4 photocatalysts, they were tested in NO(g) photo-oxidation under visible (VIS) light. The effects of polycondensation temperature on the structure and photocatalytic performance of mpg -C 3 N 4 in NO photo-oxidation were studied. The results revealed that polycondensation temperature has a dramatic effect on the photocatalytic activity of mpg -C 3 N 4 in NO photo-oxidation, where mpg -C 3 N 4 synthesized at 500 ℃ (mpg -CN500) showed the best performance in NO x abatement as well as a high selectivity towards solid state NO x storage under VIS light illumination. Photocatalytic performance of the mpg -CN500 was further enhanced by the anchoring of 8.0 ± 0.5 wt.% Fe 3 O 4 nanoparticles (NPs) on it. Fe 3 O 4 / mpg -CN500 photocatalyst showed both high activity and high selectivity along with extended reusability without a need for a regeneration step. Enhanced photocatalytic NO x oxidation and storage efficiency of Fe 3 O 4 / mpg -CN500 photocatalyst was attributed to their mesoporous structure, high surface area and slow electron-hole recombination kinetics, efficient electron-hole separation and facile electron transfer from mpg -CN500 to Fe 3 O 4 domains enhancing photocatalytic O 2 reduction, while simultaneously suppressing nitrate photo-reduction and decomposition to NO 2 (g). [ABSTRACT FROM AUTHOR]

Abstract This article describes the synthesis, characterization and in vivo cytotoxic evaluation of thiol-functionalized superparamagnetic iron oxide magnetic nanoparticles (SPIONs). They have been employed as potential vehicles for a large number of biomedical applications, such as drug delivery. Fe 3 O 4 nanoparticles were synthesized by coprecipitation of iron salts and coated with L-cysteine. The physicochemical, morphological, and magnetic properties of Cys-Fe 3 O 4 nanoparticles were characterized by different experimental techniques. To evaluate their applicability in nanomedicine we evaluated their cytotoxicity using Balb/C mice. The results show that Cys-SPIONs are good candidates as nanocarriers in biomedical applications. Graphical abstract Unlabelled Image Highlights • Cys-Fe3O4 shows superparamagnetic behavior at room temperature. • Cys-Fe3O4 NPs show good colloidal stability. • Successful application of Cys-Fe3O4 as a biocompatible carrier in in vivo assays • The NPs do not interfere in ferric homeostasis. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Despite the advances in molecularly targeted therapies, delivery across the blood-brain barrier (BBB) and the targeting of brain tumors remains a challenge. Like brain, bone is a common site of metastasis and requires therapies capable of discerning the tumor from its healthy cellular milieu. To tackle these challenges, we made a variation on the previously proposed concept of the earthicle and fabricated an aqueous, surfactant-free ferrofluid containing superparamagnetic iron oxide nanoparticles (SPIONs) coated with silicate mesolayers and carbon shells, having 13 nm in size on average. Nanoparticles were synthesized hydrothermally and characterized using a range of spectroscopic, diffractometric, hydrodynamic and electron microscopy techniques. The double coating on SPIONs affected a number of physicochemical and biological properties, including colloidal stability and cancer targeting efficacy. Nanoparticles decreased the viability of glioblastoma and osteosarcoma cells and tumors more than that of their primary and non-transformed analogues. They showed a greater preference for cancer cells because of a higher rate of uptake by these cells and a pronounced adherence to cancer cell membrane. Even in an ultralow alternate magnetic field, nanoparticles generated sufficient heat to cause tumor death. Nanoparticles in MDCK-MDR1 BBB model caused mislocalization of claudin-1 at the tight junctions, underexpression of ZO-1 and no effect on occludin-1 and transepithelial resistance. Nanoparticles were detected in the basolateral compartments and examination of LAMP1 demonstrated that nanoparticles escaped the lysosome, traversed the BBB transcellularly and localized to the optic lobes of the third instar larval brains of Drosophila melanogaster. The passage was noninvasive and caused no adverse systemic effects to the animals. In conclusion, these nanoparticulate ferrofluids preferentially bind to cancer cells and, hence, exhibit a greater toxicity in these cells compared to the primary cells. They are also effective against solid tumors in vitro , can cross the BBB in Drosophila, and are nontoxic based on the developmental studies of flies raised in ferrofluid-infused media. Statement of Significance We demonstrate that a novel, hydrothermally synthesized composite nanoparticle-based ferrofluid is effective in reducing the viability of osteosarcoma and glioblastoma cells in vitro , while having minimal effects on primary cell lines. In 3D tumor spheroids, nanoparticles greatly reduced the metastatic migration of cancer cells, while the tumor viability was reduced compared to the control group by applying magnetic hyperthermia to nanoparticle-treated spheroids. Both in vitro and in vivo models of the blood-brain barrier evidence the ability of nanoparticles to cross the barrier and localize to the brain tissue. These composite nanoparticles show great promise as an anticancer biomaterial for the treatment of different types of cancer and may serve as an alternative or addendum to traditional chemotherapies. [ABSTRACT FROM AUTHOR]

Highlights • Impact of differently modified dextran coated nanoparticles on HEWL fibrillization. • Nanoparticles inhibit formation of HEWL fibrils in concentration-dependent manner. • Size of nanoparticles influenced the extent of their inhibitory properties. • The highest inhibitory effect was observed for the smallest CMdex NPs. • Dextran coated nanoparticles are not toxic at concentration close to IC 50 values. Abstract More than 50 diseases are associated with a conversion of proteins or peptides from their soluble functional states to highly organized fibrillar aggregates called amyloid fibrils. Due to the specific physico-chemical properties, specifically designed iron oxide nanoparticles may be an effective strategy for inhibiting the amyloid fibrillization of proteins. The inhibitory effect of three types of iron oxide nanoparticles coated with differently modified dextran on lysozyme fibrils formation was studied by Thioflavin T assay and atomic force microscopy. The size and zeta potential of studied nanoparticles were determined by dynamic light scattering. It had been found that nanoparticles are able to inhibit formation of lysozyme amyloid aggregates in concentration-dependent manner. Our results suggest that size of nanoparticles influenced the extent of their inhibitory properties. Moreover, the most effective nanoparticles were not toxic after 48 h incubation with neuroblastoma SH-SY5Y cell line at concentration close to IC 50 values. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Magnetic nanomaterials were formed by pulsed laser ablation of iron in water and air. • Material ablated in water contained spherical particles of Fe 3 O 4 , Fe 2 O 3 , FeO and Fe. • Material ablated in air contained more Fe 3 O 4 and nitrogen (N-O, N-H or FeN x) • The surface composition and electrokinetic properties of the materials differed. • Material obtained in air is more stable in colloids due to its surface composition. Abstract Magnetic nanomaterials were synthesized using a method of pulsed laser ablation of an iron target in water (PLAL) and in air (PLAG). The microstructure and composition of the obtained materials differed. Spherical nanoparticles (NPs) of 2–80 nm containing Fe 3 O 4 , α-Fe 2 O 3 , γ-Fe 2 O 3 , FeO and Fe were obtained using PLAL. According to the XPS and FTIR data, the surfaces of these particles contained both Fe 3 O 4 and Fe 2 O 3. PLAG led to the formation of NPs of 2–120 nm and 2-D lamellar structures up to 1 μm. This material contained more magnetite and nitrogen species, presumably iron nitrides. This material's surface contained FeOOH; the OH-group content was very high. It exhibited the greatest sedimentation stability and zeta potential value, while magnetic NPs (MNPs) obtained in water were less stable in colloids. The difference in the magnetic parameters of the two materials can be connected to not only the different composition (different magnetite content and nitrogen species presence) but also their structural features. Thus, PLAL and PLAG methods allowed for obtaining magnetic nanostructured materials with different characteristics suitable for application in different fields. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The engineering of iron oxide nanoparticles (IONPs) for biomedical use has received great interest over the past decade. In the present study we investigated the biocompatibility of IONPs grafted with linear (2P) or generation 1 (2PG1) or 2 (2PG2) dendronized oligoethyleneglycol units in THP-1-derived macrophages. To evaluate IONP effects on cell functionality and homeostasis, mitochondrial function (MTT assay), membrane permeability (LDH release), inflammation (IL-8), oxidative stress (reduced glutathione, GSH), NLRP3 inflammasome activation (IL-1β) and nanoparticle cellular uptake (intracellular iron content) were quantified after a 4-h or 24-h cell exposure to increasing IONP concentrations (0–300 µg Fe/mL). IONPs coated with a linear molecule, NP10COP@2P, were highly taken up by cells and induced significant dose-dependent IL-8 release, oxidative stress and NLRP3 inflammasome activation. In comparison, IONPs coated with dendrons of generation 1 (NP10COP@2PG1) and 2 (NP10COP@2PG2) exhibited better biocompatibility. Effect of the dendritic architecture of the surface coating was investigated in a kinetic experiment involving cell short-term exposure (30 min or 1 h 30) to the two dendronized IONPs. NP10COP@2PG2 disrupted cellular homeostasis (LDH release, IL-1β and IL-8 secretion) to a greater extend than NP10COP@2PG1, which makes this last IONP the best candidate as MRI contrast or theranostic agent. [ABSTRACT FROM AUTHOR]

Abstract The super-paramagnetic iron oxide nanoparticles (SPIONs) were synthesized using an environmentally friendly method. The SPIONs with mainly carbohydrate coatings were simply synthesized using a natural, zero calorie sweetener (Stevia) extract (as both reducing and stabilizing agents). The resulting SPIONs were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), High-resolution transmission electron microscopy (HRTEM), thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), vibrating-sample magnetometer (VSM) and Zeta potential test. The SPIONs (smaller than 25 nm) are very stable due to bio-molecular coating because having a zeta potential of −41.1 mV creates opposing forces between nanoparticles and prevents them from gathering. The biogenic SPIONs were able to counteract the effects of oxidative metabolites as studied with the antioxidant activity with an IC 50 of 65 μg/ml. This feature shows the capability of these nanoparticles in designing potential biomedical applications. Graphical abstract Schematic representation of green synthesis of the magnetic iron oxide nanoparticles. Image Highlights • Fe 3 O 4 iron oxide nanoparticles was smaller than 25 nm in size. • The magnitude of the potential Zeta was calculated −41.1 mV. • These biogenic NPs can easily be collected or removed from the environments. [ABSTRACT FROM AUTHOR]

Abstract Magnetic hyperthermia is one of the most effective methods for treatment of cancer. In this work we discuss synthesis of magnetic iron oxide nanorods (IONRds) and their application for enhanced magnetic hyperthermia. By microwave irradiation the monodisperse water-soluble IONRds with clear morphology were obtained. Magnetic measurements showed that such IONRds have high value of coercivity (141 Oe). Moreover, hyperthermia experiments with synthesized samples were carried out. At the frequency and field strength of alternating magnetic field (AMF) f = 261 kHz H = 20 kA m−1 the specific absorption rate (SAR) and intrinsic loss power (ILP) values were equal to 147 W g−1 and 1.4 nHm2 kg−1 respectively, which confirms the efficiency of synthesized nanorods in hyperthermia applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Pulsed laser ablation of iron in air led to magnetite and iron nitrides formation. • Lamellas and rolls appear in the sample that was ablated in air, not in Ar-O 2 mixture. • Thermal treatment allowed control of the composition and structure of the material. • Materials obtained with different properties are in demand for different applications. Abstract Magnetic nanoparticles were obtained using the nanosecond pulsed laser ablation (Nd:YAG laser, 1064 nm, 7 ns) of an iron target in air at atmospheric pressure. The particles obtained were further annealed at four different temperatures. The composition, structure and properties of all obtained powders were investigated using X-ray diffraction (XRD), DSC, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, TEM, SAED and other techniques. The initial sample was found to contain monoclinic magnetite and iron nitrides. Presumably, magnetite presents in the form of spherical particles with the distribution maximum of 12–15 nm, and nitrides take the form of lamellas and rolls. Thermal treatment of the sample led to particle enlargement and phase transformations, first, to cubic magnetite, then to a Fe 3 O 4 , α-Fe 2 O 3 and γ-Fe 2 O 3 mixture, and finally to the pure hematite phase. Zeta-potential, BET surface area and magnetic properties changed with the annealing as well. The obtained materials exhibited different properties that make them in demand in different fields, from biomedicine to technology. [ABSTRACT FROM AUTHOR]

Tunable, one-dimensional (1D) nanofiller assembly using oscillating magnetic fields in the low frequency range (<5 Hz) is studied as a scalable and energy-efficient method to structure nanofillers within viscous matrices to deliver anisotropic, multi-functional polymer nanocomposites (PNCs). In this work 1D assembly tailoring was first experimentally studied and demonstrated using the model system of superparamagnetic iron oxide nanoparticles (SPIONs, 15 nm, 0.02–0.08 vol%) in DI water using varying magnetic fields (0–5 Hz frequency, 10–100 G magnetic flux density, and square and sinusoidal waveforms). In addition to lateral assembly of nanofillers, when the field oscillation is turned on, transverse assembly can be introduced as the magnetic moments of the particles respond to the changing fields by Brownian rotation. The degree of transverse assembly, in balance with lateral assembly and the resulting nanofiller patterns, was observed to be determined by the magnetic field parameters, magnetic responsiveness of the nanofillers, and the matrix viscosity. Based on this assembly study, PNCs consisting of ferrimagnetic iron oxide nanofillers in a thermoset polymer, with two different linear nanoparticle patterning, were successfully fabricated using small magnetic fields (<100 G) even in a viscous matrix (70 cP) with a short assembly time of 30 min. This work can contribute to scalable manufacturing and thus bulk application of multi-functional PNCs enabled by more precise nanofiller and interface structuring. [ABSTRACT FROM AUTHOR]

A laser-based technology is presented for fabrication of oriented nanowires composed by nanoparticles. The nanowires were produced by nanosecond pulsed laser deposition in air at atmospheric pressure in the presence of an external magnetic field. The technology described is relevant to the preparation of nanowires of magnetic materials. Applying an external magnetic field during the deposition resulted in the formation of nanowires with lengths of a few microns oriented longitudinally to the magnetic field lines. The influence was investigated of the process parameters, namely, laser fluence, target-substrate distance, and wavelength used for ablation, on the morphology of the deposited samples. It was found that the degree of the nanowires’ orientation increased with the increase of the target-substrate distance. Also, the density of the deposited material was influenced by the laser fluence applied and by the wavelength used. [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]

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]

Magnetic nanoparticles (MNPs) have gained significant attention among several nanoscale materials during the last decade due to their unique properties. These properties make them successful nanofillers for drug delivery and a number of new biomedical applications. MNPs are more useful when combined with biodegradable polymers. In this review, we discussed the synthesis of polycaprolactones (PCL) and the various methods of synthesizing magnetic iron oxide nanoparticles. Then, the synthesis of composites that is made of PCL and magnetic materials (with special focus on iron oxide nanoparticles) were highlighted. In addition, we comprehensively reviewed their application in drug delivery, cancer treatment, wound healing, hyperthermia, and bone tissue engineering. Other biomedical applications of the magnetic PCL such as mitochondria targeting are highlighted. Moreover, biomedical applications of magnetic nanoparticles incorporated into other synthetic polymers apart from PCL are also discussed. Thus, great progress and better outcome with functionalized MNPs enhanced with polycaprolactone has been recorded with the biomedical applications of drug delivery and recovery of bone tissues. [Display omitted] • Methods of synthesizing polycaprolactones (PCL) polymer were discussed. • Composites made from PCL and magnetic nanoparticles were examined. • Biomedical applications of the magnetic composites were comprehensively reviewed. • Performance of other non-PCL polymeric composites were highlighted. [ABSTRACT FROM AUTHOR]

A co-precipitation synthesis method was used to obtain iron oxide nanoparticles coated with Yerba Mate ( Ilex paraguariensis ) extract. These particles have a core–shell structure with the iron oxide phase surrounded by an organic shell provided by an organic component which come from the Yerba Mate extract. Obtained nanoparticles were exhaustively characterized as powders and in aqueous colloidal suspensions using several techniques such as TEM, XRD, SAXS, TGA, ATR-FTIR, Raman and XPS spectroscopy, magnetic moment measurement and specimen ac susceptibility. All results together show that the obtained particles are single-crystal iron oxide particles with magnetite as the most probable phase. Yerba Mate extract shell mass to iron oxide core mass, m S /m c , could be increased up to 6.2 × 10 −2 , depending on the synthesis conditions. As a function of m S /m c the crystallite size of the nanoparticles decreased from about 15 nm to 11 nm, while saturation magnetization Ms and coercive field Hc of powders decreased . Ms. diminution was associated to increasing modification of core surface electronic states due to chemical bond of iron in iron oxide to Yerba Mate extract components; on the other hand, coercivity reduction was modelled on the basis of the increasing interparticle separation and dipolar interaction weakening, which occurs as shell thickness grows. Differences between the particle core mean size obtained with TEM, SAXS, XRD and magnetic measurements are observed. The fact that magnetic size was smaller than particle and crystallite sizes was attributed to the existence of intense dipolar interactions. It was found that low field susceptibility in a colloid sample was about 2.5 times that of the powder specimen, a result that shows that demagnetizing effects prevail in the powder specimen, while they may be absent in the colloid due to the larger interparticle mean separation expected in the latter. Analysis of powder and colloid susceptibility was done based on a recently developed model was in agreement with the one performed for the coercive field behaviour. [ABSTRACT FROM AUTHOR]

Releases of crude oil and other types of oil from numerous sources can impose catastrophic physical, chemical, and biological effects on aquatic ecosystems. While currently-used oil removal techniques possess many advantages, they have inherent limitations, including low removal efficiencies and waste disposal challenges. The present study quantified the synergistic interactions of polyvinylpyrrolidone (PVP) coated magnetite nanoparticles (NP) and oil-degrading bacteria for enhanced oil removal at the laboratory scale. The results showed that at relatively high oil concentrations (375 mg L −1 ), NP alone could remove approximately 70% of lower-chain alkanes (C9–C22) and 65% of higher-chain (C23–C26), after only 1 h, when magnetic separation of NP was used. Removal efficiency did not increase significantly after that, which was likely due to saturation of the NP with oil. Microbial bioremediation, using strains of oil-degrading bacteria, removed almost zero oil immediately but 80–90% removal after 24–48 h. The combination of NPs and oil-degrading bacterial strains worked effectively to remove essentially 100% of oil within 48 h or less. This was likely due to the sorption of oil components to NPs and their subsequent utilization by bacteria as a joint Fe and C source, although the mechanisms of removal require further testing. Furthermore, results showed that the emission of selected volatile organic compounds (VOCs) and semi volatile organic compounds (SVOCs) were reduced after addition of NPs and bacteria separately. When combined, VOC and SVOC emissions were reduced by up to 80%. [ABSTRACT FROM AUTHOR]

We report a nanoparticulate iron oxide based catalyst for CO 2 conversion with high efficiency at low pressures and on the effect of the presence of copper on the catalyst’s restructuring and its catalytic performance. In situ X-ray scattering reveals the restructuring of the catalyst at the nanometer scale. In situ X-ray absorption near edge structure (XANES) shows the evolution of the composition and oxidation state of the iron and copper components under reaction conditions along with the promotional effect of copper on the chemical transformation of the iron component. X-ray diffraction (XRD), XANES and Raman spectroscopy proved that the starting nanocatalyst is composed of iron oxides differing in chemical nature (α-Fe 2 O 3 , Fe 3 O 4 , FeO(OH)) and dimensionality, while the catalyst after CO 2 conversion was identified as a mixture of α-Fe, Fe 3 C, and traces of Fe 5 C 2 . The significant increase of the rate CO 2 is turned over in the presence of copper nanoparticles indicates that Cu nanoparticles activate hydrogen, which after spilling over to the neighbouring iron sites, facilitate a more efficient conversion of carbon dioxide. [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]

Nitrogen-doped carbon-coated and graphene oxide-wrapped Fe 3 O 4 nanoparticles were prepared using the electrostatic force between polyethyleneimine-functionalized Fe 3 O 4 nanoparticles and graphene oxide layers, followed by annealing in an N 2 atmosphere (Fe 3 O 4 @NCG). The electrochemical performance of Fe 3 O 4 @NCG was superior to that of graphene oxide- or reduced graphene oxide-wrapped Fe 3 O 4 nanoparticles and carbon-coated Fe 3 O 4 nanoparticles. Fe 3 O 4 @NCG exhibited stable specific capacity of ∼895 mAh g −1 after 350 cycles over the voltage range 0.001–3.0 V vs. Li/Li + . The superior performance of Fe 3 O 4 @NCG was attributed to the presence of a nitrogen-doped carbon layer and networks of reduced graphene oxide. The chemical route-derived Fe 3 O 4 @NCG may be a promising anode material for high-performance lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Ferrihydrite in natural environment is commonly produced in the presence of significant amounts of Al and low molar mass organic impurities, which affect the surface reactivity of ferrihydrite depending on the impurity levels. Here, we investigated the effect of citrate on the species and levels of Al impurities in ferrihydrite. Al-bearing ferrihydrite was synthesized at different citrate/(Fe + Al) and Al/(Fe + Al) molar ratios. The samples were then characterized by chemical analysis, TEM, XRD, XPS and FTIR. The results showed that citrate promoted the formation of stable colloidal ferrihydrite particles, and induced Al accumulation in colloidal fraction at the citrate/(Fe + Al) ratio of 25% as well as in the surface layer of ferrihydrite at the citrate/(Fe + Al) ratios of 25 and 50 mol%. DFT analysis showed that Al-for-Fe substitution was closely related to the particular sites in ferrihydrite structure. We also estimated the mass of citrate (or aluminum citrate complexes) required to occupy the reactive sites on ferrihydrite nanoparticles. The results revealed that with increasing citrate content, the surface reactive sites favorable for Al-substitution of ferrihydrite became occupied by adsorbed citrate, which partially inhibited the substitution of Fe by Al but increased the adsorption of Al through Al-citrate surface complexation. [ABSTRACT FROM AUTHOR]

In this letter, a simple and efficient cathodic electrosynthesis (CE) platform is reported for preparation of magnetite nanoparticles (MNPs). In this procedure, surface capped MNPs (with size of ∼10 nm) were prepared from the Fe(III)nitrate/ethanol bath through CE process without using any coating agent. The prepared MNPs were characterized by different techniques of XRD, FE-SEM, TEM, FT-IR, TGA, DLS and VSM. It was found that solvent act as capping agent during the CE process, where surface of the deposited MNPs are capped with ethoxy groups i.e. -C 2 H 5 O. The VSM data proved superparamagnetic behavior of the prepared MNPs (i.e. M s = 44.84 emu g −1 , Mr = 0.21 emu g −1 and Ce = 1.38 Oe). The obtained results implied that the developed CE strategy is an effective one-pot method for preparation of surface capped MNPs. [ABSTRACT FROM AUTHOR]

In this letter, Fe 3 O 4 ultra-fine nanoparticles are prepared through PEG-assisted cathodic electrosynthesis from ethanol media. The XRD, FE-SEM, TEM and BET data confirmed the pure phase (i.e. magnetite), fine particle size (∼5 nm) and high surface (176.7 m 2 /g) of the electro-synthesized product. The electrochemical evaluations through cyclic voltammetry (CV) and continuous charge-discharge (GCD) techniques proved that the prepared Fe 3 O 4 nanoparticles have excellent capacitive storage as high as 218.3 F g −1 and stable cycling performance of 4.7% decay after 2000 cycling at 0.5 A g −1 . Furthermore, this work provides a facile electrochemical procedure to fabricate high performance iron oxide electrode for use in supercapacitors. [ABSTRACT FROM AUTHOR]

In this paper we report synthesis of aqueous based gold coated iron oxide nanoparticles to integrate the localized surface plasma resonance (SPR) properties of gold and magnetic properties of iron oxide in a single system. Iron oxide-gold core shell nanoparticles were stabilized by attachment of thiolated sodium alginate to the surface of nanoparticles. Transmission electron microscope (TEM) micrograph presents an average elementary particle size of 8.1 ± 2.1 nm. High resolution TEM (HR-TEM) and X-ray photon spectroscopy further confirms the presence of gold shell around iron oxide core. Gold coating is responsible for reducing saturation magnetization (M s ) value from ~ 41 emu/g to ~ 24 emu/g – in thiolated sodium alginate stabilized gold coated iron oxide core-shell nanoparticles. The drug (curcumin) loading efficiency for the prepared nanocomposites was estimated to be around 7.2 wt% (72 μg drug/mg nanoparticles) with encapsulation efficiency of 72.8%. Gold-coated iron oxide core-shell nanoparticles could be of immense importance in the field of targeted drug delivery along with capability to be used as contrast agent for MRI & CT. [ABSTRACT FROM AUTHOR]

A facile strategy developed for the fabrication of composite material comprising mesopores and representing an iron oxide core/encapsulated in carbon nanodisk shell using Fe-based MOF as precursor. Catalytic carbonization of Fe 2+ coordinated 1,4,5,8 -naphthaleneteracarboxylic dianhydride MOF at 725 °C under N 2 atmosphere followed by air treatment at 300 °C yielded Fe 3 O 4 nanoparticles encapsulated in mesoporous carbon matrix (FeMCNA-300). The XRD and N 2 adsorption studies confirm the presence of Fe 3 O 4 nanoparticles and mesopores in the carbon matrix, respectively. MOF precursor generates mesopores of narrow pore size distribution without aid of structure directing agent in the carbon shell through straightforward catalytic reduction of core iron oxide. FeMCNA-300 demonstrated outstanding catalytic activity towards the degradation of 150 ppm of methylene blue (MB) dye in water with 84% TOC conversion in 15 min at room temperature. MB and oxidant H 2 O 2 interact with iron oxide nanoparticles through confined mesoporous channel in the FeMCNA-300 carbon nanodisk. This permits the generated OH at the surface of magnetite nanoparticles to instantly oxidize the MB molecules adsorbed in the close proximity. FeMCNA-300 under ultra-sonication decolourise MB completely with high TOC conversion of about 84% at maximum iron leaching of 2% up to five successive recycles. [ABSTRACT FROM AUTHOR]

The present work describes the successful fabrication of iron oxide nanoparticles (Fe 3 O 4 NPs) through a green approach using the gum extract of the Bombax malabaricum (B. malabaricum) plant. The bioactive molecules/phytochemicals present in the gum extract of B. malabaricum were found to be responsible for the synthesis and fabrication of engineered nanoparticles (NPs). The Fe 3 O 4 NPs were characterized via UV-VIS, FTIR, and TEM. As indicated by TEM micrographs, the uniform rounded-shaped NPs with an average mean diameter of 09 ± 02 nm were observed. The antibacterial activity of Fe 3 O 4 NPs was investigated against 3 g-positive bacterial strains (Staphylococcus aureus , Bacillus halodurans, and Micrococcus luteus) and 1 g-negative bacterial strain (Escherichia coli) respectively. The antifungal activity of Fe 3 O 4 NPs against the fungal species of Aspergillus niger and Aspergillus flavus was also investigated. The methodologies of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide (H 2 O 2) radical scavenging assays were also utilized to evaluate the antioxidant potential of synthesized NPs. The enhanced biomedical applications of these NPs were attributed to the extremely small size of the synthesized NPs. Furthermore, the photocatalytic potential of Fe 3 O 4 NPs was also studied by using the degradation reaction of the model pollutant of methylene blue (MB) dye. The influence of the reaction variables on the response (i.e. degradation percentage; D%) was investigated by using two different optimization approaches designated as one-factor-at-a-time (OVAT) and response surface methodology (RSM) approaches. The comparative analysis of these strategies adds to the novelty of our work as the modeling of the photocatalytic reaction via statistics is a rare approach and requires investigation. The RSM exhibited better D% results (98.721%) in comparison to OVAT (94.23%) indicating that rather than the conventional OVAT approach, the RSM should be utilized for the optimization of the MB dyes. Furthermore, it was observed that MB dose acted as the main rate-limiting factor for optimizing the reaction. These additional insights regarding photocatalysis can only be acquired by using the statistical modeling approach. [ABSTRACT FROM AUTHOR]

Size and shape are crucial parameters which have impact on the potential of nanoparticles to penetrate cell membranes and epithelial barriers. Current research in nanotoxicology additionally focuses on particle coating. To distinguish between core- and coating-related effects in nanoparticle uptake and translocation, two nanoparticles equal in size, coating and charge but different in core material were investigated. Silver and iron oxide nanoparticles coated with poly (acrylic acid) were chosen and extensively characterized by small-angle x-ray scattering, nanoparticle tracing analysis and transmission electron microscopy (TEM). Uptake and transport were studied in the intestinal Caco-2 model in a Transwell system with subsequent elemental analysis. TEM and ion beam microscopy were conducted for particle visualization. Although equal in size, charge and coating, the behavior of the two particles in Caco-2 cells was different: while the internalized amount was comparable, only iron oxide nanoparticles additionally passed the epithelium. Our findings suggest that the coating material influenced only the uptake of the nanoparticles whereas the translocation was determined by the core material. Knowledge about the different roles of the particle coating and core materials in crossing biological barriers will facilitate toxicological risk assessment of nanoparticles and contribute to the optimization of pharmacokinetic properties of nano-scaled pharmaceuticals. [ABSTRACT FROM AUTHOR]

Polymeric materials that contain magnetic nanoparticles are extremely useful in many applications including as multifunctional drug carriers, imaging contrast agents, or scaffold material. There is a need for biomaterials with appropriate chemical, mechanical, and magnetic properties that also have the ability to degrade or dissolve over time so they can be eliminated from the body following use. In this work, we explore the use of iron oxide nanoparticle (IONP) formation in poly(vinyl alcohol) (PVA) as a crosslinking method in conjunction with physical crosslinking achieved using low temperature thermal cycling (LTTC). PVA-IONP hydrogels were fabricated and characterized. IONPs contribute to the crosslinking of the PVA-IONP material, and their subsequent removal reduces crosslinking, and therefore stability, of the material, allowing dissolution to occur. Dissolution studies were performed on PVA-IONP hydrogels and dissolution was compared for films in solutions of varying pH, in the presence of iron chelating agents, and in simulated physiological and tumor conditions in cell culture media. Iron release, mass loss, and mechanical testing data was collected. This work demonstrates the ability of this biomaterial to ‘degrade’ over time, which may be very advantageous for applications such as drug delivery. This importance of this work extends to other areas such as the use of stimuli-responsive hydrogels. Statement of Significance This manuscript explores the stability of an iron oxide nanoparticle (IONP)-containing, physically crosslinked poly(vinyl alcohol) (PVA) hydrogel. The PVA-IONP hydrogel’s stability is imparted through crosslinks created through a low temperature thermal cycling process and through the IONPs. Subsequent IONP removal reduces crosslinks so material dissolution can occur, resulting in a ‘degradable’ and multifunctional biomaterial. PVA-IONP films were fabricated, characterized and evaluated in terms of dissolution in solutions of varying pH and in the presence of chelating agents. Iron release, mass loss, and mechanical testing data demonstrate the ability of the PVA-IONP biomaterial to ‘degrade’ over time. This degradability has not yet been demonstrated for crosslinked PVA hydrogels. These results are relevant to the development of degradable multifunctional drug carriers, image contrast agents, or magnetic scaffold materials. [ABSTRACT FROM AUTHOR]

Novel environment friendly inorganic hybrid pigments with bright red colors and good stability were successfully prepared by a one-pot hydrothermal reaction of natural attapulgite (APT) with Fe(III) salts, without addition of any chemical precipitants. It has been revealed by systematic structure characterizations that APT is essential to form the red hybrid pigment, and the Fe 2 O 3 nanoparticles were in-situ formed and anchored on APT to form a stable composite. The hybrid pigment with the composition of 29.61% SiO 2 and 68.37% Fe 2 O 3 showed bright red color with the a * coordinate value of + 36.3, which was better than the same kinds of commercial red pigments. The color of the hybrid pigments can be tuned by only altering the dosage of Fe(III) or reaction time, and accordingly a series of hybrid pigments with the colors of light amber, orange red and bright red were obtained. Moreover, the red hybrid pigments can tolerate lights, acids, alkalis and organic solvents, and suspend well in water and alcohol media, and are able to be easily coated on different substrates, e.g., glass, wood, ceramic, cotton fabric, and paper. [ABSTRACT FROM AUTHOR]

In the present work, surface modification of iron oxide (Fe 3 O 4 ) nanoparticles with biocompatible fluorapatite (FAP) coating achieved by a simple method and their characterizations using XRD, TEM, FT-IR, DSC and VSM are reported. TEM images revealed the spherical morphology of Fe 3 O 4 nanoparticle and rod-like FAP coated Fe 3 O 4 nanoparticles with size of about 12 and 30 nm, respectively. Magnetic measurements (M-H) of both the samples exhibited superparamagnetic behavior at 300 K. FAP coated Fe 3 O 4 nanoparticles enhance the cell viability and colloidal stability when compared to Fe 3 O 4 nanoparticles. These results demonstrate that FAP coated Fe 3 O 4 nanoparticles could be a suitable candidate for biomedical applications. [ABSTRACT FROM AUTHOR]

Oil can be released into the environment from different sources such as runoff, accidental oil spills and oily wastewater discharges produced during industrial activities and can have dramatic impacts on the environment. The limitations of current clean-up techniques have inspired researchers to study the application of nanotechnology for oil remediation. Previously, we reported excellent oil-removal efficiency of a reference MC252 oil using polyvinylpyrrolidone (PVP)-coated magnetic nanoparticles (NPs) from an oil-water mixture under a wide range of environmentally relevant conditions. In the current report, the same type of NPs were used with a high gradient magnetic separation (HGMS) technique for the rapid removal of oil from oil-water mixtures in a continuous flow system. Using a high magnetic field (0.56 T) and 1 h mixing time, fluorescence and inductively coupled plasma-optical emission spectrometer (ICP-OES) data showed approximately 85–95% oil and NP removal under all conditions. Gas chromatography–mass spectrometry (GC–MS) results show 88 and near 100% removal of alkanes (C9-C22) for experiments in the presence or absence of stainless steel wool, respectively. Continuous use over 7 h of operation (17 L oil-water mixture was treated) showed no reduction in oil and NP removal capacity. Results showed that increasing the magnetic field and inserting stainless steel wool significantly increased oil and NP removal efficiencies. This study shows that using HGMS is a promising technique for oil remediation using PVP-coated magnetic NPs. [ABSTRACT FROM AUTHOR]

The functionalization of Fe 3 O 4 /γ-Fe 2 O 3 nanoparticles (NPs) gas sensors with Pd NPs was studied. NPs films were deposited from the mixtures of Fe 3 O 4 /γ-Fe 2 O 3 and Pd NPs colloidal solutions by modified Langmuir-Schaefer technique onto Al 2 O 3 substrates, the NP size being 6–7 nm. Samples were composed from 4 Fe 3 O 4 /γ-Fe 2 O 3 NP monolayers (MLs), either pure or doped by Pd at the different NPs Pd: Fe 3 O 4 /γ-Fe 2 O 3 proportions. NPs and films were studied by DLS, GI XRD, SEM and EDS. Sensors were tested toward acetone vapors and NO 2 at concentration range of 5–200 ppm and 0.5–12 ppm respectively in dry air and under working temperatures range 200–500 °C. Before testing 1 nm, surfactant capping was removed by UV irradiation. Pd-doped Fe 3 O 4 /γ-Fe 2 O 3 sensors showed p-type gas response, higher conductance and higher conduction activation energies compared to pure Fe 3 O 4 /γ-Fe 2 O 3 sensor that gives n-type gas response. Results are explained in terms of surface interactions with oxidizing and reducing species, and electrical conduction mechanisms. [ABSTRACT FROM AUTHOR]

Hematite (Fe 2 O 3 ) nanoparticles and reduced graphene oxide (rGO) were supersonically sprayed onto copper current collectors to create high-performance, binder-free lithium ion battery (LIB) electrodes. Supersonic spray deposition is rapid, low-cost, and suitable for large-scale production. Supersonic impact of rGO sheets and Fe 2 O 3 nanoparticles on the substrate produces compacted nanocomposite films with short diffusion lengths for Li + ions. This structure produces high reversible capacity and markedly improved capacity retention over many cycles. Decomposition of lithium oxide generated during cycling activates the solid electrolyte interface layer, contributing to high capacity retention. The optimal composition ratio of rGO to Fe 2 O 3 was 9.1 wt.%, which produced a reversible capacity of 1242 mAh g −1 after N = 305 cycles at a current density of 1000 mA g −1 (1C). [ABSTRACT FROM AUTHOR]