Artykuły w czasopismach: „Hematite nanomaterial”

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Zhang, Wen, Joseph Hughes i Yongsheng Chen. "Impacts of Hematite Nanoparticle Exposure on Biomechanical, Adhesive, and Surface Electrical Properties of Escherichia coli Cells". Applied and Environmental Microbiology 78, nr 11 (30.03.2012): 3905–15. http://dx.doi.org/10.1128/aem.00193-12.

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ABSTRACTDespite a wealth of studies examining the toxicity of engineered nanomaterials, current knowledge on their cytotoxic mechanisms (particularly from a physical perspective) remains limited. In this work, we imaged and quantitatively characterized the biomechanical (hardness and elasticity), adhesive, and surface electrical properties ofEscherichia colicells with and without exposure to hematite nanoparticles (NPs) in an effort to advance our understanding of the cytotoxic impacts of nanomaterials. Both scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed thatE. colicells had noticeable deformation with hematite treatment for 45 min with a statistical significance. The hematite-treated cells became significantly harder or stiffer than untreated ones, as evidenced by indentation and spring constant measurements. The average indentation of the hematite-treatedE. colicells was 120 nm, which is significantly lower (P< 0.01) than that of the untreated cells (approximately 400 nm). The spring constant of hematite-treatedE. colicells (0.28 ± 0.11 nN/nm) was about 20 times higher than that of untreated ones (0.01 ± 0.01 nN/nm). The zeta potential ofE. colicells, measured by dynamic light scattering (DLS), was shown to shift from −4 ± 2 mV to −27 ± 8 mV with progressive surface adsorption of hematite NPs, a finding which is consistent with the local surface potential measured by Kelvin probe force microscopy (KPFM). Overall, the reported findings quantitatively revealed the adverse impacts of nanomaterial exposure on physical properties of bacterial cells and should provide insight into the toxicity mechanisms of nanomaterials.

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IQBAL, Tunzeel, Shahid IQBAL i Fozia BATOOL. "SACCHARUM MUNJA DERIVED BIOCHAR LOADED WITH HEMATITE NANOMATERIAL FOR REMEDIATION OF CHROMIUM(III) FROM AQUEOUS ENVIRONMENT: ISOTHERMAL, ERROR ANALYSIS, KINETIC AND THERMODYNAMIC STUDIES". European Journal of Materials Science and Engineering 7, nr 1 (20.03.2022): 49–71. http://dx.doi.org/10.36868/ejmse.2022.07.01.049.

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Three forms of Saccharum munja had been utilized for a comparison among uptake of chromium metal from aqueous media. Scanning electron microscope characterization of sorbents revealed microporous and tubular structure in modified nanomaterial. Fourier transform infrared analysis explored different surface attaching ionic groups like hydroxyl, carbonyl also nitro groups, responsible for metal uptake from solution. Experiments on concentration factor suggested maximum percent sorption capacity of 89.65 by hematite loaded Saccharum munja biochar. Adsorption equilibrium data implication on isotherms and error functions favored experimental findings. Calculation of two forms of different isotherms for example Dubinin-Radushkevich, Langmuir, Temkin and Freundlich isotherm supported adsorption experiments with high R2>0.9 values for all sorbents. Error analysis indicated favorable results by five errors but chi-square test error values were minimum in both linear data and non-linear data. Kinetic modeling results indicated high rate of adsorption as shown by their large R2 value and closely related k, Qe and h values. Thermodynamic results showed that biosorption reactions were endothermic and spontaneous. These results also suggest that hematite loaded nanomaterials are good biosorbents for chromium metal uptake in minimum concentration and high output. Desorption study was essential for recovery of nanomaterial to be used again and again in experiments.

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Jeyavenkatesh, M., J. Arunodaya i Trilochan Sahoo. "ONE POT POLYOL SYNTHESIS OF Fe2O3-Fe3O4 NANO COMPOSITES AND THEIR STRUCTURAL, OPTICAL, PROPERTY STUDIES". IOP Conference Series: Materials Science and Engineering 1219, nr 1 (1.01.2022): 012043. http://dx.doi.org/10.1088/1757-899x/1219/1/012043.

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Abstract The magnetic iron oxides are classified into three phases known as Magnetite (Fe3O4), Magnetite (-Fe2O3), Hematite (-Fe2O3).The ferric oxide synthesis with the excess of the ferrous oxide nanoparticles was carried out by the co-precipitation method. The precursors Ferric sulphate hydrate and Ferrous sulphate heptahydrate taken in the molar ratio of 1:2 in 100 ml of water and 30 ml of Hydrochloric acid added to initiate precipitation at 90 OC with vigorous stirring the ammonia solution was added. The prepared materials are characterized by XRD, and UV-Vis spectroscopy. The XRD showed formation of phase and crystallization of the nanomaterial is prepared. The UV-Vis spectroscopy used to determine the reflectance and absorptance as well as the optical bandgap of the nanomaterial, in the range of 800 nm to 200 nm. The analysis indicated formation of ferrous oxide impregnated ferric oxide nanoparticles with desired optical band gap.

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Kalaitzidou, Kyriaki, Evangelia Pagona, Paraskevas Stratigousis, Xanthi Ntampou, Vasileios Zaspalis, Anastasios Zouboulis i Manassis Mitrakas. "Hematite Nanoparticles Addition to Serpentine/Pyroxenes By-Products of Magnesite Mining Enrichment Process for the Production of Refractories". Applied Sciences 12, nr 4 (17.02.2022): 2094. http://dx.doi.org/10.3390/app12042094.

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The present study focuses on the refractory upgrade and reuse of the mining wastes/by-products of the magnesite mine “Grecian Magnesite SA” (Chalkidiki, N. Greece), by the addition of hematite (α-Fe2O3) nanomaterial. These by-products were also examined after the application of thermal pre-treatment, i.e., treated at 850 °C for 30 min, prior to sintering. Different thermal treatments and times were applied, aiming to induce the formation of forsterite and attempting to examine the respective effects on the refractory properties of up-cycled products. The results indicate that hematite addition of 5 wt.% can improve the major refractory parameters of products, whereas the applied thermal pre-treatment was not found to be particularly beneficial. Nevertheless, the optimum results were realized after thermal treatment at 1300 °C for 120 min heating time, also revealing that the initial mineralogical content of the examined mineral wastes is a key factor for the subsequent upgrade ranking of the final product.

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Verdugo, Edgard M., Yang Xie, Jonas Baltrusaitis i David M. Cwiertny. "Hematite decorated multi-walled carbon nanotubes (α-Fe2O3/MWCNTs) as sorbents for Cu(ii) and Cr(vi): comparison of hybrid sorbent performance to its nanomaterial building blocks". RSC Advances 6, nr 102 (2016): 99997–100007. http://dx.doi.org/10.1039/c6ra16332g.

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Hybrid nanostructured sorbents were fabricatedviathe deposition and growth of hematite nanoparticles on carbon nanotubes, and fundamental aspects of their performance toward common heavy metal pollutants were evaluated.

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H Gurlhosur, Shrikrishna, Dr Sreekanth B i . "Synthesis, Characterization of Iron Oxide (Α-Fe2o3) Nanoparticles and its Application in Photocatalytic Reduction of Cadmium (Ii)". International Journal of Engineering & Technology 7, nr 3.34 (1.09.2018): 388. http://dx.doi.org/10.14419/ijet.v7i3.34.19234.

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The α-Fe2O3 Nanoparticles were successfully synthesized by Sol-Gel method and the powder was calcinated at 4000. SEM, XRD, FTIR, EDX studies were carried out for characterization. The XRD confirmed that nanoparticles were Hematite (α-Fe2O3 ) having crystalline size of 11.55nm which confirms the Hematite(α-Fe2O3) on comparison with obtained spectra against Joint Committee on Powder Diffraction Standards Database(JCPDS) and SEM morphology indicated that IronOxide Nanoparticles were of flower shape at higher magnifications . The FTIR showed the bonds between functional groups and Fe-O group, O-H bending and vibration bonds. The presence of FeO, Fe, C, in nanomaterial was confirmed by EDX . Synthesized iron oxide α-Fe2O3 (Hematite) crystalline size of 11.55nm was used in the study of photo catalytic reduction of Cadmium (II) .Different parameters like Metal concentration, Dosage of Nanoparticles, Contact time and pH were studied. pH maintained for the solutions of different concentrations were 4,5,6,7 and 10. Concentration of cadmium solution taken for the study were 2,4,6,8 and 10ppm. Keeping concentration and dosage constant, pH was varied. Then concentration was varied by keeping dosage and pH constant. Then dosage was varied by keeping concentration and pH constant. Dosage of iron oxide taken was 50 mg, 75mg, 100mg, 125 mg and 150mg. It was observed that photo catalytic reduction by Iron oxide nanoparticles (IONP) was more effective at metal concentration 4ppm, IONP dosage 100mg, pH 5, and contact time of 150 min with 97.02% reduction of Cadmium (II).

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Alrobei, Hussein, Hye Young Lee, Ashok Kumar i Manoj K. Ram. "p-n Based Photoelectrochemical Device for Water Splitting Application Alpha-Hematite (α-Fe2O3)-Titanium Dioxide (tio2) as N-Electrode & Polyhexylthiophene (rrphth) - Nanodiamond (ND) as P-Electrode". MRS Advances 3, nr 13 (2018): 697–706. http://dx.doi.org/10.1557/adv.2018.299.

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ABSTRACTRecently, photoelectrochemical (PEC) water splitting using semiconductor photoanode has received great attention due production of hydrogen through clean energy. The alpha hematite (α Fe2O3) is one of the candidate amongst photoanodic materials, which is chemically stable, abundant in nature with a band gap of 2.0-2. 2eV allowing to be harvesting in the visible light. However, it has also drawn back due to high recombination rate of electron–hole pair revealing the low concentration of charges and lower device performance. In common with α-Fe2O3, the titanium dioxide (TiO2) has been known as one of the most explored photoanode electrode material due to its physical and chemical stability in aqueous and non-toxicity. However, TiO2 has large bandgap (3.0-3.2 eV) that results in absorbing UV light and very small part of visible region. Incorporation of TiO2 in α-Fe2O3 could achieve better efficiencies as photoanode materials by enhancing the electric conductivity, limited hole diffusion length, and both materials can absorb light in both UV and visible spectrum range. However, the photoanodic properties of α-Fe2O3 with different concentrations of TiO2 are mostly unknown. Under this work, α-Fe2O3-TiO2 nanomaterial was synthesized using a hydrothermal method. The α-Fe2O3-TiO2 nanomaterials containing different weight percentage (2.5, 5, 16, 25, and 50) of TiO2 to α-Fe2O3 were characterized using SEM, XRD, UV-Vis, FTIR and Raman techniques, respectively. The electrochemical properties of α-Fe2O3-TiO2 nanomaterials were investigated by cyclic voltammetry and chronoamperometry techniques, respectively.

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Wang, Yanhu, Huihui Shi, Kang Cui, Lina Zhang, Shenguang Ge, Mei Yan i Jinghua Yu. "Hierarchical hematite/TiO2 nanorod arrays coupled with responsive mesoporous silica nanomaterial for highly sensitive photoelectrochemical sensing". Biosensors and Bioelectronics 117 (październik 2018): 515–21. http://dx.doi.org/10.1016/j.bios.2018.06.030.

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Iqbal, Tunzeel, Shahid Iqbal, Fozia Batool, Dimitrios Thomas i Malik Muhammad Hassnain Iqbal. "Utilization of a Newly Developed Nanomaterial Based on Loading of Biochar with Hematite for the Removal of Cadmium Ions from Aqueous Media". Sustainability 13, nr 4 (18.02.2021): 2191. http://dx.doi.org/10.3390/su13042191.

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In order to conserve the energy used for remediation of harmful metals from aqueous media, an adsorption process was performed. It is efficient and low-cost method with zero carbon emissions as compared to other methods. A hematite-based novel nanomaterial loaded onto biochar was utilized for the remediation of toxic cadmium metal ions from aqueous media. Saccharum munja has been employed as low-cost feedstock to prepare the biochar. Three adsorbents i.e., raw Saccharum munja (SM), Saccharum munja biochar (SMBC) and hematite-loaded Saccharum munja bichar (HLSMBC) were used in batch adsorption tests to study uptake of metal ions by optimizing the experimental parameters. Experimental data and calculated results revealed maximum sorption efficiency of Cd(II) removal was given by HLSMBC (72 ppm) and SMBC (67.73 ppm) as compared with SM (48.7 ppm). Among adsorption isotherms applied on work best fit for Cd(II) adsorption on SM was found for a Freundlich isotherm with high values of correlation coefficient R2 ≥ 0.9 for all sorbents and constant 1/n values between 0–1. Equilibrium results were evaluated using five different types of errors functions. Thermodynamic studies suggested feasible, spontaneous and endothermic nature of adsorption process, while, the ∆H parameter < 80 kJ/mol indicated physiosorption and positive ∆S values promoted randomness of ions with increase in adsorption process. Data fitted into type I of pseudo second order kinetics having R2 ≥ 0.98 and rate constants K2 (0–1). Desorption process was also performed for storage, conservation and reuse of sorbent and sorbate materials.

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Susilawati, D. Pangga, M. Zainuri, A. Doyan, S. Prayogi i M. R. Bilad. "SYNTHESIS AND CHARACTERIZATION OF BARIUM MHEXAFERRITE BaFe12-2xCoxZnxO19 (0 ≤ X ≤ 1) PREPARED FROM CO-PRECIPITATION". RASAYAN Journal of Chemistry 16, nr 02 (2023): 845–56. http://dx.doi.org/10.31788/rjc.2023.1626810.

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Barium hexaferrite (BaFe12O19) has attracted research attention due to its diverse applications. This study reports the synthesis of barium M-hexaferrite (BaFe12-2xCoxZnxO19) powder using co-precipitation of BaCO3 and FeCl3.6H2O powder, Co and Zn powder as a dopant material on the variation of x = 0, 0.2, 0.4, 0.6, 0.8, and 1. Results show that co-precipitation is an effective method for the synthesis of nanomaterial barium M-hexaferrites (BaFe12-2xCoxZnxO19) containing >89% of Fe elements and an average particle size of 50 nm. The DTA/TGA analyses show phase transformation at T ≤ 285°C and T = 750-840°C. The results of refinement using the Rietveld method show that the barium M-hexaferrite phase begins to form at low temperatures, with the best yield at x = 0.4. At high temperatures T > 740°C, it tends to form single-phase α-Fe2O3 (hematite). Substitution ion dopant Co/Zn only slightly changes the lattice parameters of the hexagonal basic crystal structure

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Soleimani, Hassan, Noor Rasyada Ahmad Latiff, Noorhana Yahya, Hasnah Mohd Zaid, Maziyar Sabet, Beh Hoe Guan i Kean Chuan Lee. "Effect of Annealing Temperature on the Crystallization of Hematite-Alumina (Fe₂O₃-Al₂O₃) Nanocomposite and its Influence in EOR Application". Journal of Nano Research 29 (grudzień 2014): 105–13. http://dx.doi.org/10.4028/www.scientific.net/jnanor.29.105.

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Usage of magnetic materials is not unusual in oil and gas research, specifically in enhanced oil recovery (EOR) where various magnetic micro-and nanoparticles were used to enhance sweep efficiency, reducing interfacial tension and heat generation. Magnetic nanoparticles which are activated by a magnetic field are anticipated to have the ability to travel far into the oil reservoir and assist in the displacement of the trapped oil. In this work, magnetic Fe2O3-Al2O3 nanocomposite was synthesized and characterized for its morphological, structural and magnetic properties. At an annealing temperature of 900°C, this nanomaterial starts to exhibit magnetization as the composite structure crystallizes to the stable Fe2O3 and Al2O3. Subsequently, dispersion of the 0.01 wt% Fe2O3-Al2O3 nanocomposite in distilled water was used for displacement tests to validate its feasibility to be applied in EOR. In the displacement test, the effect of electromagnetic waves on the magnetization of Fe2O3-Al2O3 nanofluid was also investigated by irradiating a 13.6 MHz square wave to the porous medium while nanofluid injection is taking place. In conclusion, an almost 20% increment in the recovery of oil was obtained with the application of electromagnetic waves in 2.4 pore volumes (PV) injection of Fe2O3-Al2O3 nanofluid.

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Sajid Hussain, Sajid Hussain, i S. F. Hasany and Syed Usman Ali S F Hasany and Syed Usman Ali. "Hematite Decorated MWCNT Nanohybrids: A Facile Synthesis". Journal of the chemical society of pakistan 44, nr 5 (2022): 480. http://dx.doi.org/10.52568/001121/jcsp/44.05.2022.

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Hybrid nanomaterials with different sizes, shapes, compositions, and morphology have gained importance for numerous physicochemical, electrical and magnetic acumens. Multi-Walled Carbon nanotubes (MWCNTs) can be decorated with various metals to produce nanohybrids to attain desired features for leading high-tech applications. The presented research work comprises a cost- effective wet chemical method to fabricate Hematite based (α-Fe2O3- MWCNTs) nanohybrids. Physicochemical characteristics were studied by XRD, FTIR, SEM and VSM, and EDX, respectively. Results showed well-decorated hematite nanocrystals (size ~ 26nm) on the surface of MWCNTs. Magnetic behaviors exhibited a ferromagnetic material with saturation and remnant magnetization and coercivity of ~ 1.2 emu/g, 0.5 emu/g and 200 Oersted respectively, which makes it a suitable contender in advanced energy storage devices.

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张, 静. "Synthesis and Application of Hematite Nanomaterials". Advances in Analytical Chemistry 13, nr 02 (2023): 164–70. http://dx.doi.org/10.12677/aac.2023.132020.

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ALROBEI, HUSSEIN, ASHOK KUMAR i MANOJ K. RAM. "ALUMINUM–α-HEMATITE THIN FILMS FOR PHOTOELECTROCHEMICAL APPLICATIONS". Surface Review and Letters 25, nr 08 (grudzień 2018): 1950031. http://dx.doi.org/10.1142/s0218625x19500318.

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In recent years, photoelectrochemical (PEC) based devices have become attractive due to production of hydrogen by splitting water using photocatalyst alpha ([Formula: see text])-hematite (Fe2O3) as an electrode material due to its bandgap, low cost, chemical stability and extreme abundance in nature. The [Formula: see text]-Fe2O3 is also related to low carrier diffusion due to higher resistivity, slow surface kinetics, low electron mobility and higher electro–hole combination. The carrier mobility and carrier diffusion properties of [Formula: see text]-Fe2O3 have been enhanced by doping as well as composite formation. Keeping in view the enhanced properties of [Formula: see text]-Fe2O3, attempt is being made to dope and form composite using trivalent “aluminum” ions. The Al–[Formula: see text]-Fe2O3 nanophotocatalytic materials were synthesized by varying the ratio of Al to [Formula: see text]-Fe2O3 using sol–gel technique. The nanomaterials “[Formula: see text]-Fe2O3 and Al–[Formula: see text]-Fe2O3” were physically characterized through X-ray diffraction, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and UV–visible techniques, respectively. The diffusion coefficient of nanomaterials at the electrode/electrolyte interface was analyzed using electrochemical analysis. Interestingly, the presence of aluminum causes the [Formula: see text]-Fe2O3 to change the structural, optical and morphological properties of nanomaterials. The bandgaps of [Formula: see text]-Fe2O3 vary from 2.2[Formula: see text]eV to 2.45[Formula: see text]eV due to presence of aluminum in the structure. The photocurrent studied on Al–[Formula: see text]-Fe2O3 based electrode clearly shows the enhanced hydrogen production under photoelectrochemical cell.

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Matulová, Michaela, Marek Bujdoš, Marcel B. Miglierini, Martin Cesnek, Eva Duborská, Katarína Mosnáčková, Hana Vojtková i in. "The Effect of High Selenite and Selenate Concentrations on Ferric Oxyhydroxides Transformation under Alkaline Conditions". International Journal of Molecular Sciences 22, nr 18 (15.09.2021): 9955. http://dx.doi.org/10.3390/ijms22189955.

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Iron-based nanomaterials have high technological impacts on various pro-environmental applications, including wastewater treatment using the co-precipitation method. The purpose of this research was to identify the changes of iron nanomaterial’s structure caused by the presence of selenium, a typical water contaminant, which might affect the removal when the iron co-precipitation method is used. Therefore, we have investigated the maturation of co-precipitated nanosized ferric oxyhydroxides under alkaline conditions and their thermal transformation into hematite in the presence of selenite and selenate with high concentrations. Since the association of selenium with precipitates surfaces has been proven to be weak, the mineralogy of the system was affected insignificantly, and the goethite was identified as an only ferric phase in all treatments. However, the morphology and the crystallinity of ferric oxyhydroxides was slightly altered. Selenium affected the structural order of precipitates, especially at the initial phase of co-precipitation. Still, the crystal integrity and homogeneity increased with time almost constantly, regardless of the treatment. The thermal transformation into well crystalized hematite was more pronounced in the presence of selenite, while selenate-treated and selenium-free samples indicated the presence of highly disordered fraction. This highlights that the aftermath of selenium release does not result in destabilization of ferric phases; however, since weak interactions of selenium are dominant at alkaline conditions with goethite’s surfaces, it still poses a high risk for the environment. The findings of this study should be applicable in waters affected by mining and metallurgical operations.

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Yu, Le, Diana N. H. Tran, Peter Forward, Martin F. Lambert i Dusan Losic. "The hydrothermal processing of iron oxides from bacterial biofilm waste as new nanomaterials for broad applications". RSC Advances 8, nr 61 (2018): 34848–52. http://dx.doi.org/10.1039/c8ra07061j.

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Lee, Jin Bae, Hae Jin Kim, Janez Lužnik, Andreja Jelen, Damir Pajić, Magdalena Wencka, Zvonko Jagličić, Anton Meden i Janez Dolinšek. "Synthesis and Magnetic Properties of Hematite Particles in a “Nanomedusa” Morphology". Journal of Nanomaterials 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/902968.

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We present the synthesis, characterization, and magnetic properties of hematite particles in a peculiar “nanomedusa” morphology. The particles were prepared from an iron-silica complex by a hydrothermal process in a solution consisting of ethyl acetate and ethanol. The particles’ morphology, structure, and chemical composition were investigated by transmission electron microscopy, powder X-ray diffraction, and scanning electron microscope equipped with an energy-dispersive X-ray spectrometer. The “hairy” particles consist of a spherical-like core of about 100 nm diameter and fibrous exterior composed of thin “legs” of 5 nm diameter grown along one preferential direction. The particles’ cores are crystalline and undergo a magnetic phase transition to a weakly ferromagnetic state at a temperature of 930 K that matches reasonably the Néel temperature of bulk hematite. However, unlike bulk hematite that undergoes Morin transition to an antiferromagnetic state around room temperature and small hematite nanoparticles that are superparamagnetic, the “nanomedusa” particles remain weakly ferromagnetic down to the lowest investigated temperature of 2 K. Each particle thus represents a nanodimensional “hairy” ferromagnet in a very broad temperature interval, extending much above the room temperature. Such high-temperature ferromagnetic nanoparticles are not frequently found among the nanomaterials.

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Matmin, Juan. "Rice Starch-Templated Synthesis of Nanostructured Silica and Hematite". Proceedings 3, nr 1 (30.08.2018): 1. http://dx.doi.org/10.3390/iocn_2018-1-05491.

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Synthesis of nanostructured materials is not straightforward, which involves the complicated use of surfactant templates. Currently, only non-renewable resources that are hazardous and toxic are used to produce the surfactant templates in the industries. This study presents an environmentally friendly and efficient route for the synthesis of the nanostructure of both silica and hematite using rice starch as a promising biomaterials template. The rice starch-templated synthesis yield both hematite and silica with nano-size and high surface area. In particular, the nanostructured silica showed a pseudo-spherical morphology with a nano-size from 13 to 22 nm, amorphous structure and surface area of 538.74 m2/g. On the other hand, the nanostructured hematite showed a spherical-shaped morphology with a nano-size from 24 to 48 nm, and surface area of 20.04 m2/g. More importantly, the use of rice starch-template for a greener approach in the synthesis of nanomaterials was successfully outlined.

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Kuncser, Andrei Cristian, Arpad Mihai Rostas, Rodica Zavoianu, Octavian Dumitru Pavel, Ioana Dorina Vlaicu, Mihaela Badea, Daniela Cristina Culita, Alina Tirsoaga i Rodica Olar. "Synthesis and Characterization of Hematite-Based Nanocomposites as Promising Catalysts for Indigo Carmine Oxidation". Nanomaterials 12, nr 14 (21.07.2022): 2511. http://dx.doi.org/10.3390/nano12142511.

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The hematite-based nanomaterials are involved in several catalytic organic and inorganic processes, including water decontamination from organic pollutants. In order to develop such species, a series of bimetallic hematite-based nanocomposites were obtained by some goethite composites-controlled calcination. Their composition consists of various phases such as α-FeOOH, α-Fe2O3 or γ-Fe2O3 combined with amorphous (Mn2O3, Co3O4, NiO, ZnO) or crystalline (CuO) oxides of the second transition ion from the structure. The component dimensions, either in the 10–30 or in the 100–200 nm range, together with the quasi-spherical or nanorod-like shapes, were provided by Mössbauer spectroscopy and powder X-ray diffraction as well as transmission electron microscopy data. The textural characterization showed a decrease in the specific area of the hematite-based nanocomposites compared with corresponding goethites, with the pore volume ranging between 0.219 and 0.278 cm3g−1. The best catalytic activity concerning indigo carmine removal from water in hydrogen peroxide presence was exhibited by a copper-containing hematite-based nanocomposite sample that reached a dye removal extent of over 99%, which correlates with both the base/acid site ratio and pore size. Moreover, Cu-hbnc preserves its catalytic activity even after four recyclings, when it still reached a dye removal extent higher than 90%.

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Zhang, Zhong Jie, i Xiang Ying Chen. "Magnetic greigite (Fe3S4) nanomaterials: Shape-controlled solvothermal synthesis and their calcination conversion into hematite (α-Fe2O3) nanomaterials". Journal of Alloys and Compounds 488, nr 1 (listopad 2009): 339–45. http://dx.doi.org/10.1016/j.jallcom.2009.08.127.

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Egodawatte, Shani, Katherine E. Greenstein, Ivy Vance, Edris Rivera, Nosang V. Myung, Gene F. Parkin, David M. Cwiertny i Sarah C. Larsen. "Electrospun hematite nanofiber/mesoporous silica core/shell nanomaterials as an efficient adsorbent for heavy metals". RSC Advances 6, nr 93 (2016): 90516–25. http://dx.doi.org/10.1039/c6ra19876g.

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Functionalized nanomaterials hold tremendous promise for water treatment because their high surface area makes them ideal sorbents for pollutants like heavy metal ions that are pervasive in global water supplies.

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Yu, Xin X. "High Visible-Light Photocatalytic Performance Of Natural Hematite Ore Composited With ZnO Nanomaterials". Advanced Materials Letters 8, nr 4 (1.08.2017): 393–97. http://dx.doi.org/10.5185/amlett.2017.7079.

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Carbajal-De la Torre, G., N. N. Zurita-Mendez, M. A. Espinosa-Medina, A. B. Martinez-Valencia i A. Sanchez-Castillo. "Synthesis of Synthetic Hematite with Substituted Aluminum by Sol-Gel Method". Materials Science Forum 793 (maj 2014): 119–25. http://dx.doi.org/10.4028/www.scientific.net/msf.793.119.

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In this work, synthetic hematite with isomorphically substituted aluminum contents were obtained by the sol-gel chemical synthesis. Nanomaterials with Fe and Al contains were obtained by the sol-gel method mixing stoichiometric mixtures of ferric chloride (FeCl3) and aluminum isopropoxide Al (OC3H7)3at 75°C. The obtained sol-gel was dried at 60 oC followed by calcinations at 400, 800 and 1100 oC. The resulting powders were characterized by X-Ray diffraction and Scanning Electron Microscopy (SEM). Preliminary results showed α-Fe2O3particles into amorphous Al-O-Fe structure, and the formation of alumina with sintering temperature. SEM characterization results, showed small size particle formation in the order of 100-200 nm, however nanosize particles could be improve by chemical parameters control and ultrasonic dispersion. Also SEM observation showed the formation and homogenous distribution of minority Fe-O phase particles between Al-O-Fe phase particles.

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Asif, Abdul Hannan, Shaobin Wang i Hongqi Sun. "Hematite-based nanomaterials for photocatalytic degradation of pharmaceuticals and personal care products (PPCPs): A short review". Current Opinion in Green and Sustainable Chemistry 28 (kwiecień 2021): 100447. http://dx.doi.org/10.1016/j.cogsc.2021.100447.

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HAN, CHENGLIANG, JINGSONG XIE, CHONGHAI DENG i DIFANG ZHAO. "A FACILE SYNTHESIS OF POROUS HEMATITE NANOMATERIALS AND THEIR FAST SORPTION OF CR (VI) IN WASTEWATER". Journal of the Chilean Chemical Society 57, nr 4 (2012): 1372–74. http://dx.doi.org/10.4067/s0717-97072012000400008.

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Zhang, Ming, Yongjing Lin, Thomas J. Mullen, Wei-feng Lin, Ling-Dong Sun, Chun-Hua Yan, Timothy E. Patten, Dunwei Wang i Gang-yu Liu. "Improving Hematite’s Solar Water Splitting Efficiency by Incorporating Rare-Earth Upconversion Nanomaterials". Journal of Physical Chemistry Letters 3, nr 21 (19.10.2012): 3188–92. http://dx.doi.org/10.1021/jz301444a.

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Zhang, Dongshi, Wonsuk Choi, Yugo Oshima, Ulf Wiedwald, Sung-Hak Cho, Hsiu-Pen Lin, Yaw Li, Yoshihiro Ito i Koji Sugioka. "Magnetic Fe@FeOx, Fe@C and α-Fe2O3 Single-Crystal Nanoblends Synthesized by Femtosecond Laser Ablation of Fe in Acetone". Nanomaterials 8, nr 8 (20.08.2018): 631. http://dx.doi.org/10.3390/nano8080631.

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There are few reports on zero-field-cooled (ZFC) magnetization measurements for Fe@FeOx or FeOx particles synthesized by laser ablation in liquids (LAL) of Fe, and the minimum blocking temperature (TB) of 120 K reported so far is still much higher than those of their counterparts synthesized by chemical methods. In this work, the minimum blocking temperature was lowered to 52 K for 4–5 nm α-Fe2O3 particles synthesized by femtosecond laser ablation of Fe in acetone. The effective magnetic anisotropy energy density (Keff) is calculated to be 2.7–5.4 × 105 J/m3, further extending the Keff values for smaller hematite particles synthesized by different methods. Large amorphous-Fe@α-Fe2O3 and amorphous-Fe@C particles of 10–100 nm in diameter display a soft magnetic behavior with saturation magnetization (Ms) and coercivities (Hc) values of 72.5 emu/g and 160 Oe at 5 K and 61.9 emu/g and 70 Oe at 300 K, respectively, which mainly stem from the magnetism of amorphous Fe cores. Generally, the nanoparticles obtained by LAL are either amorphous or polycrystalline, seldom in a single-crystalline state. This work also demonstrates the possibility of synthesizing single-crystalline α-Fe2O3 hematite crystals of several nanometers with (104), (113), (116) or (214) crystallographic orientations, which were produced simultaneously with other products including carbon encapsulated amorphous Fe (a-Fe@C) and Fe@FeOx core-shell particles by LAL in one step. Finally, the formation mechanisms for these nanomaterials are proposed and the key factors in series events of LAL are discussed.

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Cursaru, Laura Madalina, Roxana Mioara Piticescu, Dumitru Valentin Dragut, Ioan Albert Tudor, Victor Kuncser, Nicusor Iacob i Florentin Stoiciu. "The Influence of Synthesis Parameters on Structural and Magnetic Properties of Iron Oxide Nanomaterials". Nanomaterials 10, nr 1 (2.01.2020): 85. http://dx.doi.org/10.3390/nano10010085.

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Magnetic iron oxides have been used in biomedical applications, such as contrast agents for magnetic resonance imaging, carriers for controlled drug delivery and immunoassays, or magnetic hyperthermia for the past 40 years. Our aim is to investigate the effect of pressure and temperature on the structural, thermal, and magnetic properties of iron oxides prepared by hydrothermal synthesis at temperatures of 100–200 °C and pressures of 20–1000 bar. It has been found that pressure influences the type of iron oxide crystalline phase. Thus, the results obtained by Mössbauer characterization are in excellent agreement with X-ray diffraction and optical microscopy characterization, showing that, for lower pressure values (<100 bar), hematite is formed, while, at pressures >100 bar, the major crystalline phase is goethite. In addition, thermal analysis results are consistent with particle size analysis by X-ray diffraction, confirming the crystallization of the synthesized iron oxides. One order of magnitude higher magnetization has been obtained for sample synthesized at 1000 bar. The same sample provides after annealing treatment, the highest amount of good quality magnetite leading to a magnetization at saturation of 30 emu/g and a coercive field of 1000 Oe at 10 K and 450 Oe at 300 K, convenient for various applications.

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Cai i Larese-Casanova. "Facile Synthesis and Reuse of Magnetic Black Carbon Magnetite (BC-Mag) for Fast Carbamazepine Removal from Water". Nanomaterials 10, nr 2 (26.01.2020): 213. http://dx.doi.org/10.3390/nano10020213.

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Magnetic carbonaceous nanomaterials are needed in water treatment applications because they can offer both carbon surfaces for sorption of organic pollutants and ease of material magnetic retrieval for regeneration and reuse. In this study, we employed a facile one-step method to synthesize a black carbon-magnetite composite (BC-Mag) by high-temperature annealing of black carbon and hematite. The nanocomposite was easily dispersed and stable in water owing to the presence of negatively charged oxygen surface functional groups. Sorption kinetics with dissolved carbamazepine showed a rapid initial uptake with equilibrium achieved within only minutes. The sorption extent can be described with the Freundlich model, and surface area normalized sorption affinity was an order of magnitude greater than conventional granular activated carbon. The sorption extent of neutral carbamazepine remained constant between pH 2–10 while surface zeta potential decreased. BC-Mag can be reused for the sorption of carbamazepine up to six times without significant loss of the sorption extent.

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Molaei, Shafagh, Mohsen Hamidpour, Hossein Shirani i Mohammad Sabet. "Investigation of factors affecting removal of arsenic from polluted water using iron-based particles: Taguchi optimization design". Revista Internacional de Contaminación Ambiental 39 (8.08.2023): 307–17. http://dx.doi.org/10.20937/rica.54830.

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Intensive research efforts have been followed to remove arsenic (As) from contaminated water to provide potable water to millions living in different countries. Adsorption is a simple and efficient way for arsenic contamination purification in water, with a pressing challenge to find a cheap and efficient adsorbent. The present paper deals with optimizing various batch parameters for the adsorption of As from solution by synthesized iron-based particles (hematite, magnetite, and zero-valent iron (ZVI)) nanomaterials using Taguchi’s optimization methodology. Taguchi’s (L27) orthogonal design with six effective factors, namely: initial As concentration, pH, contact time, adsorbent type, size, and dose, was applied for the multivariate optimization in adsorption studies for As to maximize the adsorption capacity along with the signal-to-noise ratio. The equilibrium studies revealed that the data were well described by Freundlich isotherm. The results showed that initial As concentration was the most important parameter in the adsorption process.

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Uwakweh, Oswald N. C., Rita Más, Carolyn Morales, Pedro Vargas, Josue Silva, Angel Rosa, Neshma Lopez, Richard Perez Moyet i Yenny Cardona. "Synthesis of SnFe2O4 Nanomaterials Via High Energy Ball Milling of SnO (Stannous) and α-Fe2O3 (Hematite) Solid Precursors". Journal of Materials Engineering and Performance 20, nr 7 (6.04.2010): 1157–62. http://dx.doi.org/10.1007/s11665-010-9632-2.

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Amreen, Khairunnisa, i Annamalai Senthil Kumar. "Highly Redox-Active Hematin-Functionalized Carbon Mesoporous Nanomaterial for Electrocatalytic Reduction Applications in Neutral Media". ACS Applied Nano Materials 1, nr 5 (20.04.2018): 2272–83. http://dx.doi.org/10.1021/acsanm.8b00337.

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Saied, Ebrahim, Salem S. Salem, Abdulaziz A. Al-Askar, Fathy M. Elkady, Amr A. Arishi i Amr H. Hashem. "Mycosynthesis of Hematite (α-Fe2O3) Nanoparticles Using Aspergillus niger and Their Antimicrobial and Photocatalytic Activities". Bioengineering 9, nr 8 (17.08.2022): 397. http://dx.doi.org/10.3390/bioengineering9080397.

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Nanoparticles (NPs) and nanomaterials (NMs) are now widely used in a variety of applications, including medicine, solar energy, drug delivery, water treatment, and pollution detection. Hematite (α-Fe2O3) nanoparticles (Hem-NPs) were manufactured in this work by utilizing a cost-effective and ecofriendly approach that included a biomass filtrate of A. niger AH1 as a bio-reducer. The structural and optical properties of Hem-NPs were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and UV-visible and Fourier-transform infrared (FTIR) spectroscopies. The results revealed that all of the studied parameters, as well as their interactions, had a significant impact on the crystallite size. The average diameter size of the biosynthesized Hem-NPs ranged between 60 and 80 nm. The antimicrobial and photocatalytic activities of Hem-NPs were investigated. The antimicrobial results of Hem-NPs revealed that Hem-NPs exhibited antibacterial activity against E. coli, B. subtilis, and S. mutans with MICs of 125, 31.25, and 15.62 µg/mL, respectively. Moreover, Hem-NPs exhibited antifungal activity against C. albicans and A. fumigatus, where the MICs were 2000 and 62.5 µg/mL, respectively. The efficiency of biosynthesized Hem-NPs was determined for the rapid biodegradation of crystal violet (CV) dye, reaching up to 97 percent after 150 min. Furthermore, Hem-NPs were successfully used more than once for biodegradation and that was regarded as its efficacy. In conclusion, Hem-NPs were successfully biosynthesized using A. niger AH1 and demonstrated both antimicrobial activity and photocatalytic activity against CV dye.

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Dey, Pritam, Rupak Roy, Kunal Vora, Riddhi Kotak, Silpi Sarkar, Tania Paul, Komal Sharma i Priya Mitra. "Removal of chromium (VI) from solution using α–Fe2O3(hematite) nanoparticles synthesized by a facile chemical route". International Journal of Experimental Research and Review 26 (30.12.2021): 35–44. http://dx.doi.org/10.52756/ijerr.2021.v26.003.

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Industrial wastewater poses a great threat to both plant and animal lives because of the presence of toxic and recalcitrant compounds. Heavy metals are one of them which have been proved biologically fatal for humans if consumed above a trace amount. Chromium or Cr(VI) is one such heavy metal that is present primarily in tannery and electroplating effluents and is needed to be removed from the wastewater. Iron oxide nanomaterials can remove Cr(VI) from industrial wastewater. This study discusses the removal of Cr(VI) from synthetic solution using iron oxide nanoparticles. The α-Fe2O3(hematite) nanoparticles were synthesized using the chemical method and characterized using SEM,XRD, and FT-IR. The nanoparticles, having an average size distribution of 10-50 nm, were used to remove Cr(VI) from their single metal solution. The chromium removal study was carried out in batch mode by varying the contact time, initial Cr(VI) concentration, adsorbent dose, and process temperature at neutral pH under continuous mechanical agitation. The percent removal efficiency of α-Fe2O3 nanoparticles at a dosage of 1 g/l was found to be 82% and 90% at initial chromium ion concentrations of 50 mg/l and 100 mg/l, respectively. The equilibrium time for both the cases was found to be 40 minutes. The highest Cr(VI) removal was achieved at an α-Fe2O3 nanoparticle dose of 3.5g/l for 50 mg/l Cr(VI) concentration. While for 100 mg/l Cr(VI) concentration, optimum α-Fe2O3 nanoparticle dose was 6g/l. Also, the optimum process temperature was determined as 303K.

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Lewis, Crystal S., Luisa Torres, Jeremy T. Miyauchi, Cyrus Rastegar, Jonathan M. Patete, Jacqueline M. Smith, Stanislaus S. Wong i Stella E. Tsirka. "Absence of cytotoxicity towards microglia of iron oxide (α-Fe2O3) nanorhombohedra". Toxicology Research 5, nr 3 (26.02.2016): 836–47. http://dx.doi.org/10.1039/c5tx00421g.

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Abstract Understanding the nature of interactions between nanomaterials, such as commercially ubiquitous hematite (α-Fe2O3) nanorhombohedra (N-Rhomb) and biological systems is of critical importance for gaining insight into the practical applicability of nanomaterials. Microglia represent the first line of defense in the central nervous system (CNS) during severe injury or disease such as Parkinson's and Alzheimer's disease as illustrative examples. Hence, to analyze the potential cytotoxic effect of N-Rhomb exposure in the presence of microglia, we have synthesized Rhodamine B (RhB)-labeled α-Fe2O3 N-Rhomb, with lengths of 47 ± 10 nm and widths of 35 ± 8 nm. Internalization of RhB-labeled α-Fe2O3 N-Rhomb by microglia in the mouse brain was observed, and a dose-dependent increase in the cellular iron content as probed by cellular fluorescence was detected in cultured microglia after nanoparticle exposure. The cells maintained clear functional viability, exhibiting little to no cytotoxic effects after 24 and 48 hours at acceptable, physiological concentrations. Importantly, the nanoparticle exposure did not induce microglial cells to produce either tumor necrosis factor alpha (TNFα) or interleukin 1-beta (IL1β), two pro-inflammatory cytokines, nor did exposure stimulate the production of nitrites and reactive oxygen species (ROS), which are common indicators for the onset of inflammation. Finally, we propose that under the conditions of our experiments, i.e. in the presence of RhB labeled-α-Fe2O3 N-Rhomb maintaining concentrations of up to 100 μg mL−1 after 48 hours of incubation, the in vitro and in vivo internalization of RhB-labeled α-Fe2O3 N-Rhomb are likely to be clathrin-dependent, which represents a conventional mechanistic uptake route for most cells. Given the crucial role that microglia play in many neurological disorders, understanding the potential cytotoxic effects of these nanostructures is of fundamental importance if they are to be used in a therapeutic setting.

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Lagos, Karina J., Bojan A. Marinkovic, Anja Dosen, Alexis Debut, Karla Vizuete, Victor H. Guerrero, Emilio Pardo i Patricia I. Pontón. "KOH-Based Hydrothermal Synthesis of Iron-Rich Titanate Nanosheets Assembled into 3D Hierarchical Architectures from Natural Ilmenite Mineral Sands". Minerals 13, nr 3 (15.03.2023): 406. http://dx.doi.org/10.3390/min13030406.

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The synthesis of titanate nanostructures from low-cost mineral precursors is a topic of continuous interest, considering not only their fundamental aspects but also the benefits of incorporating such nanomaterials in a wide variety of applications. In this work, iron-rich titanate nanosheets were synthesized from Ecuadorian ilmenite sands (ilmenite–hematite solid solution-IHSS) through an alkaline hydrothermal treatment (AHT) using potassium hydroxide (KOH). The effect of the duration of the KOH-AHT was assessed at 180 °C for 24, 48, 72, and 96 h. The morphology evolution over time and the plausible formation mechanisms of titanate nanostructures were discussed. The most significant morphological transformation was observed after 72 h. At this time interval, the titanate nanostructures were assembled into well-defined 3D hierarchical architectures such as book-block-like arrangements with open channels. Based on X-ray powder diffraction (XRPD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) analyses, it was determined that these nanostructures correspond to iron-rich layered titanates (Fe/Ti mass ratio of 7.1). Moreover, it was evidenced that the conversion of the precursor into layered nanostructures was not complete, since for all the tested reaction times the presence of remaining IHSS was identified. Our experiments demonstrated that the Ecuadorian ilmenite sands are relatively stable in KOH medium.

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Hoque, Md Ariful, Marcelo I. Guzman, John P. Selegue i Muthu Kumaran Gnanamani. "Chemical State of Potassium on the Surface of Iron Oxides: Effects of Potassium Precursor Concentration and Calcination Temperature". Materials 15, nr 20 (21.10.2022): 7378. http://dx.doi.org/10.3390/ma15207378.

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Potassium is used extensively as a promoter with iron catalysts in Fisher–Tropsch synthesis, water–gas shift reactions, steam reforming, and alcohol synthesis. In this paper, the identification of potassium chemical states on the surface of iron catalysts is studied to improve our understanding of the catalytic system. Herein, potassium-doped iron oxide (α-Fe2O3) nanomaterials are synthesized under variable calcination temperatures (400–800 °C) using an incipient wetness impregnation method. The synthesis also varies the content of potassium nitrate deposited on superfine iron oxide with a diameter of 3 nm (Nanocat®) to reach atomic ratios of 100 Fe:x K (x = 0–5). The structure, composition, and properties of the synthesized materials are investigated by X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Fourier-transform infrared, Raman spectroscopy, inductively coupled plasma-atomic emission spectroscopy, and X-ray photoelectron spectroscopy, as well as transmission electron microscopy, with energy-dispersive X-ray spectroscopy and selected area electron diffraction. The hematite phase of iron oxide retains its structure up to 700 °C without forming any new mixed phase. For compositions as high as 100 Fe:5 K, potassium nitrate remains stable up to 400 °C, but at 500 °C, it starts to decompose into nitrites and, at only 800 °C, it completely decomposes to potassium oxide (K2O) and a mixed phase, K2Fe22O34. The doping of potassium nitrate on the surface of α-Fe2O3 provides a new material with potential applications in Fisher–Tropsch catalysis, photocatalysis, and photoelectrochemical processes.

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Kopanja, Lazar, Boris Lončar, Dragiša Žunić i Marin Tadić. "Nanoparticle shapes: Quantification by elongation, convexity and circularity measures". Journal of Electrical Engineering 70, nr 7 (1.12.2019): 44–50. http://dx.doi.org/10.2478/jee-2019-0040.

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Abstract The goal of the nanoparticle synthesis is, first of all, the production of nanoparticles that will be more similar in size and shape. This is very important for the possibility of studying and applying nanomaterials because of their characteristics that are very sensitive to size and shape such as, for example, magnetic properties. In this paper, we propose the shape analysis of the nanoparticles using three shape descriptors – elongation, convexity and circularity. Experimental results were obtained by using TEM images of hematite nanoparticles that were, first of all, subjected to segmentation in order to obtain isolated nanoparticles, and then the values of elongation, convexity and circularity were measured. Convexity Cx(S) is regarded as the ratio between shape’s area and area of the its convex hull. The convexity measure defines the degree to which a shape differs from a convex shape while the circularity measure defines the degree to which a shape differs from an ideal circle. The range of convexity and circularity values is (0, 1], while the range of elongation values is [1, ∞). The circle has lowest elongation (ε = 1), while it has biggest convexity and circularity values (Cx = 1; C = 1). The measures ε(S), Cx(S), C(S) proposed and used in the experiment have the few desirable properties and give intuitively expected results. None of the measures is good enough to describe all the shapes, and therefore it is suggested to use a variety of measures so that the shapes can be described better and then classify and control during the synthesis process.

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Khurram, Rooha, Zaib Un Nisa, Aroosa Javed, Zhan Wang i Mostafa A. Hussien. "Synthesis and Characterization of an α-Fe2O3-Decorated g-C3N4 Heterostructure for the Photocatalytic Removal of MO". Molecules 27, nr 4 (21.02.2022): 1442. http://dx.doi.org/10.3390/molecules27041442.

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This study describes the preparation of graphitic carbon nitride (g-C3N4), hematite (α-Fe2O3), and their g-C3N4/α-Fe2O3 heterostructure for the photocatalytic removal of methyl orange (MO) under visible light illumination. The facile hydrothermal approach was utilized for the preparation of the nanomaterials. Powder X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), and Brunauer–Emmett–Teller (BET) were carried out to study the physiochemical and optoelectronic properties of all the synthesized photocatalysts. Based on the X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance (DRS) results, an energy level diagram vs. SHE was established. The acquired results indicated that the nanocomposite exhibited a type-II heterojunction and degraded the MO dye by 97%. The degradation ability of the nanocomposite was higher than that of pristine g-C3N4 (41%) and α-Fe2O3 (30%) photocatalysts under 300 min of light irradiation. The formation of a type-II heterostructure with desirable band alignment and band edge positions for efficient interfacial charge carrier separation along with a larger specific surface area was collectively responsible for the higher photocatalytic efficiency of the g-C3N4/α-Fe2O3 nanocomposite. The mechanism of the nanocomposite was also studied through results obtained from UV-vis and XPS analyses. A reactive species trapping experiment confirmed the involvement of the superoxide radical anion (O2•−) as the key reactive oxygen species for MO removal. The degradation kinetics were also monitored, and the reaction was observed to be pseudo-first order. Moreover, the sustainability of the photocatalyst was also investigated.

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He, Jianzhou, Dengjun Wang, Tingting Fan i Dongmei Zhou. "Cotransport of Cu with Graphene Oxide in Saturated Porous Media with Varying Degrees of Geochemical Heterogeneity". Water 12, nr 2 (7.02.2020): 444. http://dx.doi.org/10.3390/w12020444.

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Graphene oxide (GO) is likely to encounter heavy metals due to its widespread use and inevitable release into the subsurface environment, where the ubiquitous presence of iron oxides (e.g., hematite) would affect their interaction and transport. The present study aimed to investigate the cotransport of GO (20 mg L−1) and copper (0.05 mM CuCl2) in the presence of varying degrees of geochemical heterogeneity represented by iron oxide-coated sand fractions (ω = 0‒0.45) in water-saturated columns under environmentally relevant physicochemical conditions (1 mM KCl at pH 5.0‒9.0). The Langmuir-fitted maximum adsorption capacity of Cu2+ by GO reached 137.6 mg g−1, and the presence of 0.05 mM Cu2+ decreased the colloidal stability and subsequent transport of GO in porous media. The iron oxide coating was found to significantly inhibit the transport of GO and Cu-loaded GO in sand-packed columns, which can be explained by the favorable deposition of the negatively charged GO onto patches of the positively charged iron oxide coatings at pH 5.0. Increasing the solution pH from 5.0 to 9.0 promoted the mobility of GO, with the exception of pH 7.5, in which the lowest breakthrough of GO was observed. This is possibly due to the fact that the surface charge of iron oxide approaches zero at pH 7.5, suggesting that new “favorable” sites are available for GO retention. This study deciphered the complicated interactions among engineered nanomaterials, heavy metals, and geochemical heterogeneity under environmentally relevant physicochemical conditions. Our results highlight the significant role of geochemical heterogeneity, such as iron oxide patches, in determining the fate and transport of GO and GO-heavy metal association in the subsurface environment.

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Buthiyappan, Archina, Abdul Raman Abdul Aziz i Wan Mohd Ashri Wan Daud. "Recent advances and prospects of catalytic advanced oxidation process in treating textile effluents". Reviews in Chemical Engineering 32, nr 1 (1.01.2016): 1–47. http://dx.doi.org/10.1515/revce-2015-0034.

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AbstractIn the past few years, there have been many researches on the use of different types of homogenous catalyst for the degradation of textile wastewater in conventional advanced oxidation processes (AOPs). However, homogenous AOPs suffer from few limitations, including large consumption of chemicals, acidic pH, high cost of hydrogen peroxide, generation of iron sludge, and necessity of post-treatment. Therefore, recently, there have been more researches that focus on improving the performance of conventional AOPs using heterogeneous catalysts such as titanium dioxide, nanomaterials, metal oxides, zeolite, hematite, goethite, magnetite, and activated carbon (AC). Besides, different supports such as AC that have been incorporated with transition metals and clays have been proven to have excellent catalytic activity in AOPs. This paper presents a comprehensive review of advances and prospects of catalytic AOPs for the decontamination of a wide range of synthetic and real textile wastewater. This review provides an up-to-date critical review of the information on the degradation of various textile dyes by a wide range of heterogeneous catalysts and adsorbents. The future challenges of AOPs, including chemical consumption, toxicity assessment, reactor design, and limitation of catalysts, are discussed in this paper. In addition, this paper also discusses the presence of ions, generation of by-products, and industrial applications of AOPs. Special emphasis is given to recent studies and large-scale combination of AOPs for wastewater treatment. This review paper concludes that more studies are needed for the kinetics, reactor design, and modeling of hybrid AOPs and the production of their corresponding intermediate products and secondary pollutants. A better economic model should also be developed to predict the cost of AOPs, as the treatment cost varies with dyes and textile effluents.

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"Electrochemical Performance of Surfactant Assisted Hematite Nanoparticles by Chemical Synthesis Method". International Journal of Recent Technology and Engineering 8, nr 4S4 (4.02.2020): 140–43. http://dx.doi.org/10.35940/ijrte.d1048.1284s419.

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Fe2O3 nanoparticles were prepared by simple chemical route. The structural, functional, morphological properties of prepared nanoparticles were obtained by Powder X-ray Diffraction analysis, Fourier transform infrared spectroscopy, and Scanning Electron Microscopy analysis respectively. The average grain size of the prepared nanoparticles was calculated using the Scherrer formula. The functional groups and metal bonding were analyzed through FTIR analysis. The external morphology of the prepared nanomaterials was analyzed with scanning electron microscopy technique. Electrochemical property of the prepared nanomaterial was examined with the help of cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy.

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Franco, Raissa, Ana Luisa Silva, Yordy Licea, Mariella Alzamora, Dalber Sánchez i Nakédia Carvalho. "Effect of Camellia sinensis Origin and Heat Treatment in the Iron Oxides Nanomaterials Composition and Fenton Degradation of Methyl Orange". Journal of the Brazilian Chemical Society, 2023. http://dx.doi.org/10.21577/0103-5053.20220140.

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Sustainable and environmentally friendly methods for nanomaterials synthesis have been emerging recently. The use of extracts of polyphenol-rich plants with high reducing and chelating power is advantageous because the polyphenol can protect the nanomaterial from agglomeration and deactivation. Green nanomaterials have been applied in several areas, including remediation of toxic organic pollutants from contaminated effluents. Herein, we describe the preparation of green iron oxide nanoparticles (IONPs) with extracts of the plant Camellia sinensis as black tea for dye removal application. The as-prepared IONPs were composed of amorphous FeOOH and FeII/III-polyphenol complexes. To obtain crystalline and pure iron-based nanomaterials, the amorphous precursor was annealed at 900 ºC. Samples of black tea from different regions were used to verify the reproducibility of the iron phases formed. The same iron phases were obtained for all black tea samples, α-Fe2O3 (hematite), FePO4, and Fe3PO7, but in different proportions. The materials were applied as heterogeneous-Fenton catalysts for the removal of the dye methyl orange. The amorphous as-prepared IONPs were more active than the respective annealed IONPs due to the proton release from the polyphenol into the reaction medium, setting the pH to around 3, which is the optimum pH for the Fenton system.

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Mohamed, Hanan H., i Dina H. A. Besisa. "Eco-friendly and solar light-active Ti-Fe2O3 ellipsoidal capsules’ nanostructure for removal of herbicides and organic dyes". Environmental Science and Pollution Research, 6.10.2022. http://dx.doi.org/10.1007/s11356-022-23119-0.

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AbstractIn this work, Ti-doped Fe2O3 with hollow ellipsoidal capsules nanostructure has been prepared in a green manner using plant extract (flax seed). This new green hematite nanomaterial has been evaluated as photocatalyst for water treatment by testing its activity for degradation of bromophenol blue dye (BPB) and 2,4-dichlorophenoxy acetic acid (2,4-D) herbicide. For a better understanding of the green material properties, a comparison with the pristine Fe2O3 nanospheres previously prepared by the same procedure is included. Structural and optical properties of the green prepared materials are studied. The results revealed the success doping of Ti4+ at Fe3+ site, without forming any of TiO2 phases. It was also found that the Ti doping resulted in the reduction of the band gap of Fe2O3 as well as changing the morphology. The Ti-doped Fe2O3 nanomaterial exhibited an enhanced photocatalytic activity either for BPB dye or for 2,4-D degradation with more than 2 times higher rate than that using pristine Fe2O3.

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Wan, Hao, Linfeng Hu, Xiaohe Liu, Ying Zhang, Gen Chen, Ning Zhang i Renzhi Ma. "Advanced hematite nanomaterials for newly emerging applications". Chemical Science, 2023. http://dx.doi.org/10.1039/d3sc00180f.

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Vayssieres, Lionel, Jinghua Guo i Joseph Nordgren. "Purpose-Built Anisotropic Metal Oxide Nanomaterials". MRS Proceedings 635 (2000). http://dx.doi.org/10.1557/proc-635-c7.8.

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ABSTRACTLarge arrays of perpendicularly oriented anisotropic nanoparticles of ferric oxyhydroxide (Akaganeite, β-FeOOH) and oxide (Hematite, α-Fe2O3) of typically 3-5 nm in diameter, self-assembled as bundles of about 50 nm in diameter and of up to 1 μm in length have been successfully grown onto polycrystalline substrates without template and/or surfactant by heteronucleation from an aqueous solution of ferric salts and their optical and electronic properties investigated.

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Jin, Xin, Dingding Wu, Cun Liu, Shuhan Huang, Ziyan Zhou, Hao Wu, Xiru Chen, Meiying Huang, Shaoda Zhou i Cheng Gu. "Facet effect of hematite on the hydrolysis of phthalate esters under ambient humidity conditions". Nature Communications 13, nr 1 (17.10.2022). http://dx.doi.org/10.1038/s41467-022-33950-1.

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AbstractPhthalate esters (PAEs) have been extensively used as additives in plastics and wallcovering, causing severe environmental contamination and increasing public health concerns. Here, we find that hematite nanoparticles with specific facet-control can efficiently catalyze PAEs hydrolysis under ambient humidity conditions, with the hydrolysis rates 2 orders of magnitude higher than that in water saturated condition. The catalytic performance of hematite shows a significant facet-dependence with the reactivity in the order {012} > {104} ≫ {001}, related to the atomic array of surface undercoordinated Fe. The {012} and {104} facets with the proper neighboring Fe-Fe distance of 0.34-0.39 nm can bidentately coordinate with PAEs, and thus induce much stronger Lewis-acid catalysis. Our study may inspire the development of nanomaterials with appropriate surface atomic arrays, improves our understanding for the natural transformation of PAEs under low humidity environment, and provides a promising approach to remediate/purify the ambient air contaminated by PAEs.

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Tadi, Kiran Kumar, i Kavitha Rani T,. "Interfacing Silver Nanoparticles with Hematene Nanosheets for the Electrochemical Sensing of Hydrogen Peroxide". Current Analytical Chemistry 19 (9.08.2023). http://dx.doi.org/10.2174/1573411019666230809102647.

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Background: Hydrogen peroxide (H2O2) is an important metabolite that plays a crucial role in enzymatic reactions in living organisms. However, it acts as a reactive oxygen species (ROS) that causes various chronic diseases. The main challenging aspects in detecting H2O2 in body cells are the ultra-lowlevel concentrations and its reactivity. Hence, it is highly essential to develop a platform for H2O2 with high sensitivity and selectivity. Objective: In this work, we report an electrochemical biosensor for hydrogen peroxide (H2O2) by interfacing 3-dimensional silver nanoparticles (Ag-NPs) with 2-dimensional hematene (HMT) nanosheets. Methods: The two-dimensional material, HMT, was exfoliated from natural iron ore hematite (α-Fe2O3) and characterized by Raman spectroscopy. The morphology of the Ag nanoparticles and HMT was imaged by scanning electron microscope. Electrochemical characterization of Ag/HMT modified glassy carbon electrode (GCE) was performed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) Results: The fabricated sensor showed a wide linearity range of H2O2 concentrations from 0.99 µM to 1110 µM and a low detection limit of 0.16 µM using CV. Further, the sensor was successfully applied for the electrochemical sensing of hydrogen peroxide using chronoamperometry (CA) from 20 µM to 1110 µM (LOD 5.5 µM). Conclusion: The proposed electrochemical sensor for H2O2 is fast responding with a high sensitivity, and shows selectivity in the presence of biologically important molecules. These consequences suggested that the formation of heterostructures between 2D and 3D nanomaterials unveils the possibility of stable and selective electrochemical sensors for bioanalytics.

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Khoshnam, Mahsa, Javad Farahbakhsh, Masoumeh Zargar, Abdul Wahab Mohammad, Abdelbaki Benamor, Wei Lun Ang i Ebrahim Mahmoudi. "α-Fe2O3/graphene oxide powder and thin film nanocomposites as peculiar photocatalysts for dye removal from wastewater". Scientific Reports 11, nr 1 (13.10.2021). http://dx.doi.org/10.1038/s41598-021-99849-x.

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AbstractIn this study, hematite graphene oxide (αFe2O3-GO) powder nanocomposites and thin-film hematite graphene oxide (αFe2O3-GO) were synthesized for application in the removal of Rhodamine B (RhB) from textile wastewater. αFe2O3-GO nanomaterials were placed onto the FTO substrate to form a thin layer of nanocomposites. Different analysis including XRD, FTIR, Raman spectra, XPS, and FESEM were done to analyze the morphology, structure, and properties of the synthesized composites as well as the chemical interactions of αFe2O3 with GO. The photocatalytic performance of two synthesized composites was compared with different concentrations of αFe2O3-GO. The results showed that powder nanocomposites are more effective than thin-film composites for the removal of RhB dye. αFe2O3-GO-5% powder nanocomposites removed over 64% of dye while thin-film nanocomposites had less removal efficiencies with just under 47% removal rate. The reusability test was done for both materials in which αFe2O3-GO-5% powder nanocomposites removed a higher rate of dye (up to 63%) in more cycles (6 cycles).

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Chen, Linfeng, Jining Xie, Kiran R. Aatre i Vijay K. Varadan. "Iron Oxide Magnetic Nanotubes and Their Drug Loading and Release Capabilities". Journal of Nanotechnology in Engineering and Medicine 1, nr 1 (4.11.2009). http://dx.doi.org/10.1115/1.4000435.

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Iron oxide magnetic nanomaterials are among the most widely used nanomaterials in nanomedicine. Due to their magnetic and structural properties, iron oxide magnetic nanotubes are extremely attractive for biomedical applications. This paper presents the synthesis of iron oxide magnetic nanotubes, and their potential applications in drug delivery. Three types of iron oxide magnetic nanotubes, i.e., hematite, maghemite, and magnetite, were synthesized using template and hydrothermal methods, and the effects of synthesis methods on the morphological and crystalline properties of the synthesized magnetic nanotubes were analyzed. The magnetization properties of the three types of synthesized magnetic nanotubes and their responses to external magnetic fields were studied. To explore their applications in drug delivery, the drug loading and release capabilities of the synthesized magnetic nanotubes were investigated. The final part of this paper discusses several important issues related to the applications of iron oxide magnetic nanotubes for drug delivery, especially the controlled release of drugs.

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