Synthesized Hematite Nanoparticles Research Articles

Structure, optical, magnetic, morphology and dielectric studies of pristine and green synthesized hematite nanoparticles

Structure, optical, magnetic, morphology and dielectric studies of pristine and green synthesized hematite nanoparticles

Enhancing the adsorption capacity of green/chemical synthesized hematite nanoparticles by copper doping: removal of toxic Congo red dye and antioxidant activity

Enhancing the adsorption capacity of green/chemical synthesized hematite nanoparticles by copper doping: removal of toxic Congo red dye and antioxidant activity

Citric acid concentration tune of structural and magnetic properties in hematite (α−Fe2O3) nanoparticles synthesized by sol−gel method

This study synthesized hematite nanoparticles using the sol-gel method. The physical properties are modified by the citric acid concentration used as fuel. The resulting sample’s rhombohedral (hexagonal) structure and space group R3c were revealed by the XRD data. The Scherer formula revealed that the crystallite size at the most substantial peak was 32.14 nm, 24.58 nm, and 23.21 nm with an increase in the citric acid concentration of 0.3 M, 0.4 M, and 0.5 M, respectively. The FTIR spectrum’s absorption band reveals the properties of hematite nanoparticles. Finally, the magnetic properties confirmed from the VSM data revealed a significant decrease in the coercive field at 935 Oe, 610 Oe, and 548 Oe as the effect of citric acid concentration increased.

Capping agent-induced variation of physicochemical and biological properties of α-Fe2O3 nanoparticles

Capping agents play a vital role in controlling the size, morphology, and monodispersity of nanoparticles. To understand a comprehensive overview of the influence of capping on the structure and properties of hematite nanoparticles (HNPs), we have synthesized hematite nanoparticles (HNPs) with narrow size distribution by an economic co-precipitation method using capping agents like sodium citrate, Polyvinyl Pyrrolidone (PVP) and starch. A comparative in-depth study of structure, morphology, and surface analysis along with thermal, optical, magnetic and electrochemical properties of synthesized capped and uncapped HNPs has been performed. The effect of capping agents on photocatalytic and antioxidant activities along with cytotoxicity of all fabricated nanoparticles was studied against MDA-MB-231 cell line causing breast cancer along with flow cytometry. Results revealed a definite improvement in grain size, crystallinity, optical, thermal and magnetic properties of HNPs is due to efficient capping. PVP has reduced the maximum of crystalline size up to 23% of HNPs and removed 98.80% of dye from wastewater among all capping agents. Our findings also suggest that PVP capped HNPs proved to be cytotoxic to the cancer cell line. Taken together, our studies will be helpful to understand the role of capping agents in determining properties of HNPs that can further help in designing engineer HNPs.

Efficient photocatalytic degradation of malachite green dye using facilely synthesized hematite nanoparticles from Egyptian insecticide cans.

In the present study, a combustion method was applied for the production of hematite nanoparticles from Egyptian iron waste using l-arginine (The sample was named HA) and glutamine (The sample was named HG) as organic fuels, respectively. XRD confirmed that the HA and HG products have crystallite sizes of 48 and 56 nm, respectively. Also, HR-TEM demonstrated that spherical and irregular shapes have an average diameter of 45 and 59 nm were observed in the HA and HG samples, respectively. Besides, FE-SEM elucidated that spherical and irregular shapes have an average size of 142 and 196 nm were observed in the HA and HG samples, respectively. In addition, FT-IR confirmed that the peaks which were detected at 518 and 430 cm-1 are because of vibrations of Fe-O bond. Moreover, the value of the energy gap for the HA and HG samples was 1.00 and 1.45eV, respectively. Furthermore, the PL emission spectra elucidated that the emission intensity of the HA sample was less than that of the HG sample. So, e-/h+recombination rate of the HA sample was less than that of the HG sample. Hence, the photocatalytic degradation of malachite green dye using the HA sample was larger than that using the HG sample. In the absence of H2O2, the % degradation of malachite green dye under the influence of UV using HA and HG samples was 46.29 and 39.72 % after 3 h, respectively. Also, in the presence of H2O2, the % degradation of malachite green dye under the influence of UV using HA and HG samples was 100 % after 60 and 70 min, respectively.

Facile and low-cost synthesis of pure hematite (α-Fe2O3) nanoparticles from naturally occurring laterites and their superior adsorption capability towards acid-dyes.

Hematite nanoparticles have a broad range of outstanding applications such as in wastewater treatment, electrolytic studies, and photoelectrochemical and superparamagnetic applications. Therefore, the development of facile and novel methods to synthesize hematite nanoparticles using low-cost raw materials is an important and timely requirement. In this study, we have developed a facile economical route to synthesize hematite nanoparticles, directly from the naturally occurring material laterite. Laterite is a rock that is rich in Fe and Al with extensive distribution in large mineable quantities in many countries around the world, though not yet utilized for major industrial applications. In this method, ferric ions in the laterite were leached out using acid and the solution obtained was hydrolyzed with slow-release hydroxyl ions which were acquired by aqueous decomposition of urea. The resulted precursor was calcined to obtain hematite nanoparticles. Characterization data shows that the final product is comprised of spherical hematite nanoparticles with a narrow particle size vs. frequency distribution with an average particle diameter of 35 nm. The synthesized product has a purity of over 98%. Furthermore, the synthesized nanoparticles show an excellent adsorption percentage as high as 70%, even when the initial dye concentration in water is 5000 ppm and the amount of material is minimal, towards acid dyes which are excessively used in textile based industries. Such acid dyes are a threat to the environment when they are released into water bodies by industries in massive quantities. Therefore synthesized hematite nanoparticles are ideal to treat dye wastewater in industrial effluents because such nanoparticles are low cost and economical, and the synthesis procedure is rather facile and effective.

Gamma radiation shielding, fire resistance and physicochemical characteristics of Portland cement pastes modified with synthesized Fe2O3 and ZnO nanoparticles

This investigation aimed to utilize the synthesized hematite nanoparticles (α-Fe2O3) as well as ZnO nanoparticles (Wurtzite phase) for enhancing the mechanical properties, textural characteristics, thermal resistance and gamma radiation shielding of ordinary Portland cement pastes. Hematite nanoparticles (NF) and ZnO nanoparticles (NZ) were synthesized from 0.5 M FeCl3·6H2O and 0.5 M zinc acetate di-hydrate (Zn(Ac)2·2H2O), respectively in presence of specific cationic surfactant (CTAB). Characterization for the synthesized nanoparticles was performed by means of XRD, SEM, TEM, and EDX analyses. The particle diameters of the prepared NF and NZ were about 20 and 70 nm, respectively. 0.5, 1, 2 and 3% NF and 0.05, 0.1 and 0.2 NZ mass % of OPC were added to OPC. The physicochemical properties for the various investigated composites were examined at different hydration up to 90 days. After 28 days of hydration, the dried hardened specimens were fired to 300, 600 and 800 °C for 3 h to investigate fire resistance. Optimum additions of NF and NZ were 2 and 0.05%, respectively. Addition of 2% NF promoted gamma radiation shielding of OPC. On contrary, addition of 0.05% NZ had a negative effect on gamma radiation shielding of OPC. XRD, TGA/DTG and SEM results showed that various hydration products such as CSH, CAH, CASH and CFH were formed in presence of NF whereas; CSH and CZH were formed in presence of NZ. Results elaborated that NF had a good catalytic activity for hydration reaction whereas, NZ served as a retarder for hydration reaction.

The effect of synthesis method on the structure,and magnetic and photocatalytic properties of hematite (α-Fe2O3) nanoparticles - research article

Samples of hematite (α-Fe 2 O 3 ) nanoparticles have been synthesized through the co-precipitation route in cetyltrimethylammoniumbromide (Hem_PR), via a citric acid sol-gel method (Hem_SG) and a modified sol-gel method inTween20 (Hem_TW), and each were annealed at three different temperatures (400, 500 and 600 °C). The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission and high-resolution electron microscopy (TEM and HRTEM), Mossbauer spectroscopy and by means of a vibrating sample magnetometer (VSM). In addition, the photocatalytic behaviour of each sample was tested on the degradation of rhodamine B (RhB) in solution. All the characterization techniques showed the formation of phases of pure hematite nanoparticles with improved crystallinity after higher temperature annealing. However, the nanoparticles synthesized in Tween 20 showed the smallest particle size and highest BET surface area, saturation magnetization and photocatalytic activity. Of particular note was the ability of Tween 20 to control the growth of the particles so that grain sizes well below 10 nm were obtained. Thus, Tween 20, when used as a surfactant in the sol-gel route, can serve to improve the physical properties of synthesized hematite nanoparticles. Keywords: Hematite, nanoparticles, Mossbauer spectroscopy, magnetic properties, Tween 20, photocatalysis

Control of the shape and size of iron oxide (α-Fe2O3) nanoparticles synthesized through the chemical precipitation method

Hematite (α-Fe2O3) nanoparticles were synthesized via a simple chemical precipitation method. The impact of varying the concentration of precursor on the crystalline phase, size and morphology of α-Fe2O3 products was explored. The characteristic of the synthesized hematite nanoparticles were evaluated by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infra-Red (FT-IR) spectroscopy, Raman spectroscopy, Differential Thermal Analysis (DTA), Thermo Gravimetric Analysis (TGA), Ultraviolet–Visible (UV–Vis) analysis and Photoluminescence (PL). XRD data revealed a rhombohedral (hexagonal) structure with the space group R-3c in all samples. Uniform spherical like morphology was confirmed by TEM and SEM. The result revealed that the particle sizes were varied between 21 and 82nm and that the increase in precursor concentration (FeCl3, 6H2O) is accompanied by an increase in the particle size of 21nm for pure α-Fe2O3 synthesized with [Fe3+]=0.05M at 82nm for pure α-Fe2O3 synthesized with [Fe3+]=0.4M. FT-IR confirms the phase purity of the nanoparticles synthesized. The Raman spectroscopy was used not only to prove that we have synthesized pure hematite but also to identify their phonon modes. The thermal behavior of compound was studied by using TGA/DTA results: The TGA showed three mass losses, whereas DTA resulted in three endothermic peaks. Besides, the optical investigation revealed that samples have an optical gap of about 2.1eV and that this value varies as a function of the precursor concentration.

Enhancement of the Bioremediation of Pyrene-Contaminated Soils Using a Hematite Nanoparticle-based Modified Fenton Oxidation in a Sequenced Approach

ABSTRACTThe effect of modified Fenton oxidation using synthesized hematite nanoparticles and sodium pyrophosphate as a chelating agent was investigated for the pretreatment of pyrene-contaminated soil in a sequence with bioremediation. Synthesized hematite nanoparticles comprised hematite according to X-ray diffraction (XRD) analysis, with particle sizes ranging between 28 and 55 nm. Three pyrene-degrading bacteria, Bacillus cereus, Acidovorax wohlfahrtii, and Bacillus thuringiensis, were isolated from hydrocarbon-contaminated soil and used as inoculums for the bioremediation. A sequence of modified Fenton oxidation-bioremediation using a synthesized hematite nanoparticles dosage of 30 mM and H2O2 concentration of 300 mM significantly enhanced the pyrene removal rate to 96%, 87%, and 82% compared to 88%, 59%, and 37%, which were obtained during the bioremediation alone for synthetically fresh, aged, and naturally contaminated soil with initial pH 7, respectively. The results of kinetic studies indicated that modified Fenton oxidation of pyrene-contaminated soil was best fitted with a pseudo-first order kinetic model. Consequently, a sequence of modified Fenton-bioremediation can effectively remediate polycyclic aromatic hydrocarbon-contaminated sites in a shorter reaction time than bioremediation alone.

One-Pot Green Synthesis of Hematite (α-Fe2O3) Nanoparticles by Ultrasonic Irradiation and Their In Vitro Cytotoxicity on Human Keratinocytes CRL-2310

Greener and ecofriendly approaches to the synthesis of hematite (α-Fe2O3) nanoparticles are important for various biomedical applications. The authors describe on a facile, one-pot method for synthesizing hematite nanoparticles (HNPs) using ultrasonic irradiation of iron(III) oxide solution containing the aqueous root extract of Arisaema amurense, which was used as both reducing and stabilizing agents. The synthesized HNPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). FT-IR analysis indicated the presence of stabilizing groups such as hydroxyl (–OH), C–O, and amide (–NH–) on the surfaces of HNPs. TEM analysis revealed the formation of near spherical HNPs of average size 24.55 ± 6.9 nm. VSM confirmed the ferromagnetic nature of the HNPs with a saturation magnetization (Ms) at 1.25 emu/g and remanent magnetization (Mr) at 0.50 emu/g at 301 K. The electrochemical behavior of glassy carbon (GC)/HNPs electrode was studied using cyclic voltammetry (CV). MTT assays of the HNPs exhibited in vitro concentration-dependent cytotoxicity to human keratinocytes CRL-2310, which indicated the synthesized HNPs are compatible with requirements for in vivo biomedical applications at lower concentrations.

Doped copolymer of polyanthranilic acid and o-aminophenol (AA-co-OAP): Synthesis, spectral characterization and the use of the doped copolymer as precursor of α-Fe2O3 nanoparticles

The copolymer of anthranilic acid and o-aminophenol (AA-co-OAP) was synthesized and characterized by IR, UV–Vis. and thermal analyses (TGA). Linear chain mode was suggested for the pure (AA-co-OAP). The effect of inclusion of MnCl2, CoCl2, NiCl2, CuCl2 and FeCl3 on the spectral, thermal and optical properties of AA-co-OAP has been studied. Octahedral stereochemistry was suggested for Fe, Mn and Ni doped AA-co-OAP, while tetrahedral and square-planar geometries were suggested for Co and Cu doped AA-co-OAP, respectively.Fe doped AA-co-OAP has been used as a precursor for α-Fe2O3 nanoparticles by thermal decomposition route at 800 °C. The obtained hematite has been characterized by XRD and TEM. The average size of the prepared nanoparticles was estimated as 34 nm. The optical band gap of the synthesized hematite nanoparticles was measured and compared with the bulk.

Arsenate adsorption onto hematite nanoparticles under alkaline conditions: effects of aging

Arsenate adsorption onto freshly synthesized hematite nanoparticles was carried out under highly alkaline conditions (~pH 10) at room temperature (21 °C). Dynamic light scattering measurements of hydrated hematite colloids ranged from 43 to 106 nm (~96 %). The measured zeta potential was 28.1 mV (±5.85) suggesting that the hematite nanoparticles were moderately stable. X-ray diffraction and Raman spectroscopy data showed that hematite was stable under the conditions tested, with no crystal modification evident at the completion of the experiment (9 days). An additional band position at ~826 cm−1 in the Raman spectra represented arsenate adsorbed onto hematite. The pH of the slurry dropped from ~10 to ~8 during the experiment; this was coincident with a drop in the aqueous concentration of arsenic (from ~121 to ~92 mg/L) as determined via inductively coupled plasma mass spectrometry (ICP-MS). ICP-MS analyses on the solid samples indicated a significant amount of arsenic partitioned to the solid phase during aging, corroborating the results of aqueous analyses. X-ray absorption spectroscopic analyses revealed that the bonding environment remained the same irrespective of the pH and the amount of arsenate adsorbed. Arsenate adsorbed onto hematite through a strong inner-sphere bidentate-mononuclear complex both before (0 days) and after (9 days) aging. These results are valuable for understanding the fate of potential contaminants in alkaline mine tailings environments where 2-line ferrihydrite frequently transforms to hematite rather than goethite.

Non-aqueous modification of synthesized hematite nanoparticles with oleic acid

A process for non-aqueous surface modification of synthesized hematite nanoparticles is presented in this paper. Oleic acid was successfully grafted onto a hematite nanoparticle surface in methanol. The FTIR results demonstrated that chemical bonding formed between oleic acid and the hematite surface. Further studies indicated that the binding mechanism between the oleic acid and the hematite surface caused monodentate interaction. The grafted density of oleic acid onto the hematite surface increased linearly at the beginning with oleic acid concentration in the treatment solution and then leveled off at high oleic acid concentration. The saturated grafted density was 2.94mmol/m2. As more oleic acid was grafted onto the hematite surface, the hydrophobicity of the hematite nanoparticle changed from hydrophilic to hydrophobic.