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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]

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]

[Display omitted] • In situ iron oxide nanoparticles were synthesized into heavy crude oil. • Magnetite and akaganeite nanoparticles in situ presented sizes of 20–43 nm. • Reaction conditions were at 200 nm3/m3 of H 2 /heavy crude oil ratio, 380 °C and 1 h. • Residue conversion was approximately 20 %. • Spent catalyst showed the iron sulfide phase, although no presulfiding was realized. We proposed a direct in situ synthesis method for iron oxide nanoparticles (NPs) along with catalytic erformance upgrading of heavy crude oil (HCO). Our method compares the upgrading of a HCO where other iron oxide nanoparticles were synthesized by a traditional thermal decomposition method of organometallic compounds in the presence of stabilizing agents and solvents of high boiling points. Furthermore, the in situ nanoparticles were extensively characterized by XRD, Mössbauer spectroscopy and TEM microscopy which confirmed the presence of magnetite and akaganeite phases, with an average diameter of 20−43 nm. Nanoparticles by thermal decomposition method were investigated by XRD, UHR-FE-SEM and HRTEM and showed the formation of magnetite nanoparticles with an average diameter of 6.7 ± 1.4 nm. Subsequently, the nanoparticles were evaluated in a batch reactor using HCO from the Golden Lane of Mexico at 44.1 bar (initial H 2 pressure) and 380 °C, for 1 h at 500 rpm. It was observed that, even under hydrogen limited conditions, there are better physicochemical properties in terms of viscosity, API gravity and heavy fractions decrease, for example, the residue conversion was about 20 % and the kinetic model was adjusted to a five lump model. The formation of the iron sulfide phase (FeS) was detected during the analysis of the spent catalyst. [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]

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]

Salt-assisted solution combustion synthesis (SSCS) method is a promising technique for synthesizing various nanopowders with ultra-fine particle size and high surface area. It is known that the introduced soluble salt into the synthesis process plays a role as a particle separator which leads to the particle size reduction. However, the potential effects of soluble salts on the thermodynamic aspects of SSCS procedure and the other physical and chemical properties of the obtained nanopowders have not been investigated in detail. In this study, various amounts of sodium chloride (1–15mol for obtaining 0.3mol iron oxide) were introduced to the iron nitrate-glycine system to investigate effect of alkali metal salt on the thermodynamics aspects of the synthesis process and the final properties of the prepared nanoparticles. Obtained results indicated that the phase composition of the synthesized nanopowders was varied from a mixture of Fe 3 O 4 +α-Fe 2 O 3 to γ-Fe 2 O 3 +α-Fe 2 O 3 , and eventually to single-phase α-Fe 2 O 3 by increasing the amount of sodium chloride. Such phase transformation suggested that the phase composition of multi-phase compounds prepared via SSCS method can be controlled by sodium chloride. Ultra-fine powders with 9 nm particle size and surface area of 148 m2/g were obtained when 11mol sodium chloride was used in the synthesis process. Magnetization of the synthesized nanoparticles were decreased from 34emu/g to 2.7emu/g due to the decrement of particle size. The combusted single-phase hematite nanopowders were submitted to the 100 mL nickel ion (Ni2+) solution with the ion concentration of 50 mg/L to explore the effect of salt on the adsorption activity of the nanoparticles. 0.4g of the synthesized powders adsorbed ~ 90% of the nickel ions within 120 min. Note that the removal percentage of the nickel ion using the synthesized hematite nanoparticle (90%) was higher than that of prepared hematite powders in the previous studies (35%). [ABSTRACT FROM AUTHOR]

In this work, a novel organic–inorganic hybrid heterogeneous catalyst was fabricated for Knoevenagel condensation. First, the surface of carbon nanotube (CNT) was covalently functionalized with poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) polyelectrolyte (i.e., organic polybase) through the surface-initiated atom transfer radical polymerization (SI-ATRP) method. Subsequently, magnetic iron oxide nanoparticles (Fe 3 O 4 NPs) (i.e., inorganic Lewis acid) are densely and homogeneously grown on the CNT surface using the CNT- g -PDMAEMA template. The as-prepared acid–base bifunctional catalyst (i.e., CNT- g -PDMAEMA/Fe 3 O 4 NPs) was investigated in the model reaction, i.e., Knoevenagel condensation between naphthol, malononitrile and benzaldehyde. The CNT- g -PDMAEMA/Fe 3 O 4 NPs catalyst shows high catalytic activity in the Knoevenagel condensation between naphthol, malononitrile and benzaldehyde due to its unique structure and specific chemical constitution. In addition, this acid–base bifunctional catalyst can be readily recovered with an applied magnetic field and reused with negligible loss in the catalytic activity even after six cycles. [Display omitted] • The acid–base bifunctional CNT- g -PDMAEMA/Fe 3 O 4 NPs catalyst exhibited high activity. • The tiny Fe 3 O 4 NPs on the CNT as acid catalyst can activate the benzaldehyde. • The rich PDMAEMA brushes on the CNT as base catalyst may activate the malononitrile. • One-pot synthesis of 2‐amino‐4 H‐chromene product was achieved under green condition. • The magnetic CNT- g -PDMAEMA/Fe 3 O 4 NPs was a reusable catalyst with ease of separation. [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]

[Display omitted] • Glucose non-enzymatic electrochemical sensor based on polyaniline, graphene and MOF. • A large surface area, enhanced electron transfer and catalytic properties. • The sensor has a wide linear range and good sensitivity. • Acceptable performance in human fluids real samples including serum and plasma. In this study, a novel highly sensitive and selective non-enzymatic glucose sensor was fabricated by coating simple and cheap graphite sheet (GS) electrodes with a proper conductive nanocomposite containing nitrogen-doped functionalized graphene (NFG), conductive polyaniline (PANI), and core–shell nanoparticles (Fe 3 O 4 @MIL-101-NH 2). The results revealed that the core centers of iron oxide nanoparticles shelled by MIL-101-NH 2 enhanced the electron transfer and led to more conductivity, also their existence caused the limitation of the MOF's low conductivity. In addition, using Fe 3 O 4 @MIL-101-NH 2 in the nanocomposite structure led to more sensitivity and selectivity at glucose monitoring due to its amine groups and unique structure. The results showed that NFG/PANI/Fe 3 O 4 @MIL-101-NH 2 nanocomposite provided a large surface area besides enhanced electron transfer and catalytic properties that lead to proper oxidation of glucose with two linear ranges of 0.5 – 10 µM and 100 µM – 25 mM and a low detection limit of 0.3 µM (S/N = 3). Furthermore, the relative standard deviation (RSD%) in all detection processes was lower than 9 %. Finally, the performance of fabricated non-enzymatic sensor (GS/NFG/PANI/Fe 3 O 4 @MIL-101-NH 2) in human fluids real samples including serum and plasma was acceptable which significantly indicates that it is toward monitoring of glucose in clinical applications. [ABSTRACT FROM AUTHOR]

The logical research on fundamentally adjusted iron oxide nanoparticles has turned out to expanded in biomedicine because of the improved activity and best biocompatibility. In this present work upgraded bio-restorative and pharmacotherapeutic property of chitosan‑iron oxide nanocomposite, which was set up by eco-friendly in situ substance technique. Characterisation of the synthesised nanocomposite by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction,(XRD) and Vibrating test magnetometer (VSM) studies reveals that highly stable spherical, electron-dense core shelled rough particles of 50-60 nm. Particle morphology of the synthesised nanocomposite utilising scanning electron microscopy (SEM) uncovers spherical; thick electron centre shelled harsh particles with the size scope of 50-60 nm. FTIR studies show that the specific interaction of practical gatherings of chitosan with iron oxide nanoparticles. Crystalline phase and magnetisation impact of the composite resolved from XRD and VSM studies. Anti-bacterial activity of the nanocomposite examined against human bacterial pathogens which suggest that the readied nanocomposite successfully restrained the development of the tried bacterial strains by recording maximum zone of inhibition, least minimum inhibition concentration (MIC) and biofilm damage against the both tested strains. 100 μg dosages of nanocomposites recorded 20.0 and 21.0 mm of the zone of inhibition against E. coli and S. aureus respectively. Biofilm restraint was additionally observed to be high in nanocomposite treatment by recording lower optical density of ethanol solubilised biofilm of both tested strains. Anticancer activity was examined against the A549 cell line by the assurance of cell feasibility as opposed to oxidative proteins, articulation example of TNF-α, Bax, PARP qualities and apoptosis. Composite prompted 50% of cytotoxicity at 80 μg/mL unmistakably uncovers cytotoxicity against A549 cells. Nanocomposite treatment revealed a high decrease of cell feasibility at all the fixation and most extreme impact seen in 100 μg. Nanocomposite treated cells demonstrated striking changes in cell morphology, the build-up of atomic material related to trademark changes in against oxidative enzymes, quality articulation design which brought about apoptosis-like necrotic cell death. The present findings would propose the conceivable usage of chitosan‑iron oxide nanocomposite as a viable remedial against safe medication pathogens and malignant growth cells. Unlabelled Image • Simple eco-friendly in situ strategy achieved exceedingly stable CS-IO nanocomposite. • Synthesised CS-IONC displayed enhanced antibacterial activity against tested bacterial strains. • Inhibition of cell viability and promoted apoptosis against A 549 cell line reveals distinct anticancer activity. [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]

• 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]

• 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]

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]

[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]

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]

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]

Benefiting from the hydrophilicity and modifiability, aminated iron oxide nanoparticles play significant roles in the construction of magnetically responsive functional materials, and are then widely used in the field of biomedicine and water purification. Using the deep eutectic solvent (DES) composed of urea and choline chloride as an electrolyte, amino-grafted water-soluble maghemite (γ -Fe 2 O 3) nanocrystals have been synthesized by organic electrolysis (DES-electrolysis). In the present work, the DES containing ferrous ions is used as the electrolyte to verify whether magnetite (Fe 3 O 4) can be prepared by that organic electrolysis strategy. The results show that, regardless of the presence or absence of ferrous ions in the DES-based electrolyte, the resulting nanocrystals are maghemite rather than magnetite. The synthesized amino-grafted γ -Fe 2 O 3 nanoparticles can also be highly and stably dispersed in water. The present work deepens the understanding of the formation mechanism of amino-grafted water-soluble maghemite nanocrystals synthesized by DES-electrolysis. [Display omitted] [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]

In this work, graphene oxide nanosheets (GO) are dual functionalized with Fe 3 O 4 nanoparticles and hydroxypropyl cellulose (CLS) for chemo/phototherapy. The TEM, XRD, FTIR, Raman, UV, TG, DLS, and VSM analyses were used to confirm the CLS and Fe 3 O 4 incorporated GO (CLS@mGO) nanobiocomposite structure. Functionalization of magnetite graphene oxide surface by CLS not only improved biocompatibility, colloidal stability, and entrapment efficiency for paclitaxel (PTX) but also accelerated PTX release. Under 808 nm laser light, the CLS@mGO-PTX nanobiocomposite displayed good photothermal features. The CLS@mGO-PTX nanobiocomposite exhibited high photothermal conversion efficiency (47.85%) and photo stability. The notable synergistic chemo/photothermal impacts have also been determined by the in vitro experiments in killing MCF-7 cancer cells. The results of these experiments exhibited that compared to single phototherapy and chemotherapy, chemo/phototherapy could more effectively kill cancer cells by synergetic anticancer impact. Therefore, the CLS@mGO-PTX nanobiocomposite has great potential for chemo/phototherapy. [Display omitted] • CLS-functionalized magnetite mGO nanobiocomposite was developed for chemo/PTT. • CLS@mGO showed enhanced biocompatibility, thermal, colloidal and photo stability. • It displayed superparamagnetic behavior and high entrapment efficiency for PTX. • A synergetic therapeutic effect was noticed when utilizing 808 nm laser and PTX. • CLS@mGO-PTX nanobiocomposite showed pH-sensitive PTX release. [ABSTRACT FROM AUTHOR]

Composite organic/inorganic latexes encapsulating iron oxide (IO) nanoparticles of maghemite (γ-Fe 2 O 3 ) were successfully synthesized by surfactant-free reversible addition-fragmentation chain transfer (RAFT)-mediated emulsion polymerization. γ-Fe 2 O 3 was first dispersed in an aqueous solution containing a statistical copolymer constituted of acrylic acid (AA) and n -butyl acrylate (BA) units, prepared by RAFT polymerization (so-called macroRAFT agent). Taking benefit from the affinity of carboxylic acid groups for iron oxide, the P(AA 10 - co -BA 10 ) macroRAFT agent was adsorbed onto the surface of IO nanoparticles leading to the formation of macroRAFT/IO clusters. The interaction between the macroRAFT agent and the IO surface was investigated by the study of the adsorption isotherms, indicating that the amount of adsorbed macroRAFT agent increased with increasing macroRAFT concentration. However, a high fraction of the macroRAFT chains (up to 47%) remained in the aqueous phase. The clusters were then engaged in batch emulsion polymerization of styrene or of methyl methacrylate (MMA)/BA mixtures. IO encapsulation was however unsuccessful, and a phase separation between the polymer and the IO clusters was observed. In contrast, semi-batch emulsion polymerization of MMA/BA (90/10 wt ratio) led to effective encapsulation. Morphology studies suggest that the formation of stable latexes containing large IO clusters mainly depends on the concentration of the macroRAFT agent and the pH. Under optimized conditions, a latex with superparamagnetic properties ( M s = 16.2 emu g −1 ) encapsulating almost all the initial IO nanoparticles was successfully produced. [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]

• Fe 3 O 4 nanoparticles are effective catalysts for heavy oil aquathermolysis. • Fe 3 O 4 nanoparticles showed the highest efficiency at 250 °C. • Fe 3 O 4 nanoparticles improved the catalytic effect of the rock minerals. • Fe 3 O 4 nanoparticles leads to viscosity, resin and asphaltenes decreasing in addition to evolved gases increasing. • Fe 3 O 4 nanoparticles adsorbed on the rock surface. • Needle coke and carbon nanotubes formed at higher temperatures on the rock surface. The past decade has seen a renewed importance in developing heavy oil reserves due to the rapid raise in energy resources' demand. The next decade is likely to witness a considerable rise in extracting these resources by thermally enhanced oil recovery methods. However, many hypotheses regarding the influence of reservoir mineral components on aquathermolysis reactions appear to be disputable. This paper outlines a new approach to model the aquathermolysis of Aschalcha's reservoir rock heavy oil in the presence and absence of iron oxide nanoparticles combined with hydrogen donor in water steam atmosphere at 200, 250, and 300 °C using different physical and chemical methods. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) have showed adsorbed spherical magnetite (Fe 3 O 4) nanoparticles with less than 100 nm size on the studied rock minerals in hydrothermal conditions. Moreover, SARA (Saturates, Aromatics, Resins and Asphaltenes) analysis, gas analysis, and gas chromatography–mass spectrometry (GC–MS) have revealed that the obtained iron oxide nanoparticles exhibit their highest catalytic activity at 250 °C comparing to 200 and 300 °C respectively. What's more, the obtained data have indicated a considerable decrease in resins (from 19.6 to 8.9 wt%) and asphaltenes compounds (from 5.1 to 1.5 wt%) in the presence of iron oxide nanoparticles comparing to the non-catalytic aquathermolysis of reservoir rock heavy oil. Contrary to resins and asphaltenes' content, it has been found that saturates' content increases significantly from 41.1% to 61.7% wt%. On another hand, the viscosity of the extracted oil has decreased almost 30 times and the gas proportion has doubled more than twice from 0.2 g to 0.43 g per 100 g of the reservoir rock sample. Interestingly, these results have been obtained in the presence of iron oxide nanoparticles at 250 °C, meanwhile, the same results have been found for the non-catalytic experiments at 300 °C. These findings confirm the significant contribution (synergistic effect) of iron oxide nanoparticles to stimulate the catalytic activity of the reservoir rock minerals. What's more, the evidence from this study suggests that the presence of iron oxide nanoparticles in hydrothermal conditions at higher temperatures leads to the formation and adsorption of heavy coke-like carbenes, carboides, needle coke as well as carbon nanotubes of 100 nm size on the surface of the reservoir rock heavy oil as confirmed by thermal analysis (TG-DSC), SEM, and drop shape analysis (DSA) data. [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]

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]

• Changing Fenton reagent from uniparental to amphiphilic by Amphiphilic Janus material. • Supporting the Production of Hydroxyl Radicals by Ultrasound. • Improving the oxidative desulfurization ability and reusability of Fenton reagent. Fe 3 O 4 was obtained by reacting FeCl 2 and FeCl 3 with polyethylene glycol, and labeled onto a amphiphilic Janus nanosheet. It was confirmed by infrared spectroscopy, SEM, AFM and EDS that the Fe 3 O 4 nanoparticles changed from hydrophilic to amphiphilic. The oxidative desulfurization performance of amphiphilic iron oxide was studied. Results showed that the Janus nanosheets labeled with Fe 3 O 4 could significantly improve the removal rate of thiophene sulfide in simulated oil synergistically with ultrasonic waves, and the desulfurization rate could reach 100%. Further, the effect of ultrasound on the sensing ability of the oil–water interface was studied and the ultrasonic attenuation coefficient was calculated. In addition to the desulfurization mechanism of Fe 3 O 4 , it was found that although the ultrasonic attenuation coefficient of the amphiphilic nanosheets was high, the number of hydroxyl radicals determined the desulfurization efficiency. The amphiphilic Fe ions were more favorable for the formation of hydroxyl radicals than the single hydrophilic ones. [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]

• In E172 pigments, nanoparticles were detectable by SAXS and TEM. • Nanoparticle number exceeded 50% for six of seven pigments. • Pigments are not toxic to human intestinal cells in vitro. • Black pigments were challenging due to magnetic properties and agglomeration. Iron oxides used as food colorants are listed in the European Union with the number E172. However, there are no specifications concerning the fraction of nanoparticles in these pigments. Here, seven E172 products were thoroughly characterized. Samples of all colors were analyzed with a broad spectrum of methods to assess their physico-chemical properties. Small-Angle X-ray Scattering (SAXS), Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), zeta-potential, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), X-ray diffraction (XRD), Brunauer-Emmett-Teller analysis (BET), Asymmetric Flow Field-Flow Fractionation (AF4) and in vitro cell viability measurements were used. Nanoparticles were detected in all E172 samples by TEM or SAXS measurements. Quantitative results from both methods were comparable. Five pigments were evaluated by TEM, of which four had a size median below 100 nm, while SAXS showed a size median below 100 nm for six evaluated pigments. Therefore, consumers may be exposed to iron oxide nanoparticles through the consumption of food pigments. [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]

An environmental friendly and cost effective method was used for the preparation of silver‑iron oxide (α-Fe 2 O 3 -Ag) nanocomposite using guava (Psidium guajava) leaf extract, which can be used as an adsorbent for decontamination of chromium (VI) ions from aqueous media. XRD analysis revealed that both Iron oxide and silver nanoparticles are crystalline in nature with face-centered cubic and rhombohedral geometry respectively. The FESEM micrographs of Fe 2 O 3 -Ag nanocomposite displayed irregular shaped particles with an average size of 50–90 nm. BET surface area analysis suggests that the prepared Fe 2 O 3 -Ag nanocomposites are mesoporous in nature with surface area of 122.72 m2/g. The adsorption of Cr(VI) was pH dependent and maximum adsorption occurred at pH = 4 with maximum adsorption capacity of 71.34 mg/g. Thermodynamic parameters reveals that the Cr(VI) adsorption on Fe 2 O 3 -Ag surface is endothermic and spontaneous in nature. The adsorbed Cr(VI) on Fe 2 O 3 -Ag surface was recovered and can be reused up to five cycles. Unlabelled Image • Psidium guajava leaves extract was used for α-Fe 2 O 3 -Ag nanocomposite synthesis. • An adsorbent for decontamination of Cr (VI) ions from water. • Maximum adsorption occurs at pH = 4. • Adsorption process is endothermic and spontaneous in nature. [ABSTRACT FROM AUTHOR]

Fe x O y nanoparticles have been prepared by hydrothermal technique in the absence and presence of 5% polymer blend of PVA/PVP as structure-directing agent. The as-prepared nanoparticles have been characterized by powder x-ray diffraction (XRD), ultraviolet visible light spectroscopy (UV–Vis), Brunauer–Emmett–Teller (BET) analysis, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), and x-ray photoelectron spectroscopy (XPS). TEM, and HRTEM results revealed that the as-prepared nanoparticles were single crystalline and had semi-spherical morphology. Also, the results revealed that the presence of the polymer blend served as a structural controlling agent as the presence of the polymer blend produced Fe 3 O 4 (magnetite) nanoparticles selectively rather than γ-Fe 2 O 3 (maghemite) nanoparticles. The reasons behind the impact of polymer blend were investigated. This method represents a facile and polymorphs-selective synthesis of iron oxide nanoparticles for different applications. Image 1069524 • Fe x O y nanoparticles had been prepared by hydrothermal technique. • Presence of the PVA/PVP served as a structural directing agent. • PVA/PVP selectively produced magnetite NPs selectively rather than maghemite NPs. [ABSTRACT FROM AUTHOR]

The effort of incorporating therapeutic drugs with imaging agents has been one of the mainstreams of nanomedicine, which holds great promise in cancer treatment in terms of monitoring therapeutic drug activity and evaluating prognostic index. However, it is still technically challenging to develop nanomedicine endowing a spatiotemporally controllable mechanism of drug release and activatable imaging capability. Here, we developed a yolk-shell type of GSH-responsive nanovesicles (NVs) in which therapeutic drug (Doxorubicin, DOX) and magnetic resonance imaging (MRI) contrast agent (ultrasmall paramagnetic iron oxide nanoparticles, USPIO NPs) formed complexes (denoted as USD) and were encapsulated inside the NVs. The formation of USD complexes is mediated by both the electrostatic adsorption between DOX and poly(acrylic acid) (PAA) polymers and the DOX-iron coordination effect on USPIO NPs. The obtained USD NVs showed a unique yolk-shell structure with restrained drug activity and quenched T 1 MRI contrast ability which, on the other hand, can respond to glutathione (GSH) and lead to drug release and T 1 contrast activation in a spatiotemporally concurrent manner. Furthermore, the USD NVs exhibited great potential to kill HCT116 cancer cells in vitro and effectively inhibit the tumor growth in vivo. This study may shed light on the design of sophisticated nanotheranostics in precision nanomedicine. Image 1 [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]

• 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]