Iron Oxides Hematite Research Articles

Development of Machine Learning Atomistic Potential for Molecular Simulation of Hematite–Water Interfaces

A novel approach for constructing a machine-learned potential energy surface (MLP) from unlabeled training data is presented. Utilizing neural networks augmented with a pool-based active learning sampling method, a potential energy surface (PES) is developed for the accurate modeling of interfaces of hematite iron oxide and water, fitting the much more expensive density functional theory (DFT). Molecular dynamics simulations were performed using this DFT-based PES to characterize the structural and energetic properties of the system. By utilizing the developed machine learning potential (MLP), it was possible to simulate much larger systems for extended periods of time, which will be important for leveraging machine learning potentials as accurate and pragmatic simulation-led molecular design and prototyping tools whilst preserving the ab initio accuracy.

High-frequency ultrasound-assisted drug delivery of chia, cress, and flax conjugated hematite iron oxide nanoparticle for sono-photodynamic lung cancer treatment in vitro and in vivo

BackgroundSono-photodynamic therapy (SPDT), which combines photodynamic (PDT) and sonodynamic (SDT) therapies with sensitizers, offers new avenues for cancer treatment. Even though new sensitizers for SPDT have been synthesized with great success, few of them are effectively used. The limited tumor-targeting specificity, inability to transport the sensitizers deeply intratumorally, and the deteriorating tumor microenvironment limit their anti-tumor effectiveness. The current study was carried out aiming at high-frequency ultrasound-assisted drug delivery of chia, cress and flax conjugated hematite iron oxide nanoparticles (CCF–HIONP) for photothermal–photodynamic lung cancer (LCA) treatment in vitro and in vivo as activated cancer treatment up-to-date modality.Materials and methodsThe study was conducted in vitro on human LCA cells (A-549) and the study protocol application groups in vivo on Swiss albino mice treated with benzo[a]pyrene only and were not received any treatment for inducing LCA, and only after LCA induction the study treatment protocol began, treatment was daily with CCF–HIONP as HIFU–SPDT sensitizer with or without exposure to laser (IRL) or high-frequency ultrasound (HIFU–US) or a combination of laser and/or high-frequency ultrasound for 3 min for 2 weeks.ResultsRevealed that HIONP can be employed as effective CCF delivery system that directly targets LCA cells. In addition, CCF–HIONP is a promising HIFU–SPS for HIFU–SPDT and when combined with HIFU–SPDT can be very effective in treatment of LCA–A549 in vitro (cell viability decreased in a dose-dependent basis, the cell cycle progression in G0/G1 was slowed down, and cell death was induced as evidenced by an increase in the population of Pre-G cells, an increase in early and late apoptosis and necrosis, and an increase in autophagic cell death) and benzo[a]pyrene LCA-induce mice in vivo (decreased oxidative stress (MDA), and ameliorated enzymatic and non-enzymatic antioxidants (SOD, GR, GPx, GST, CAT, GSH, and TAC) as well as renal (urea, creatinine) and hepatic (ALT, AST) functions, induced antiproliferative genes (caspase 3,9, p53, Bax, TNFalpha), suppressed antiapoptotic and antiangiogenic genes (Bcl2,VEGF respectively) and effectively reducing the growth of tumors and even leading to cancer cell death. This process could be attributed to photochemical and/or high-frequency sono-chemical activation mechanism HIFU–SPDT.ConclusionsThe results indicate that CCF–HIONP has great promise as an innovative, effective delivery system for selective localized treatment of lung cancer that is activated by HIFU–SPDT.

Green synthesis, characterization and drug-loaded iron oxide nanoparticles derived from Nerium oleander flower extract as a nanocarrier for in vitro antibacterial efficacy

Application of drug conjugated iron oxide hematite (α-Fe2O3) nanoparticles are of tremendous interest in biomedicine nowadays. Meanwhile, green production of iron oxide nanoparticles is gaining favour due to its sustainability, ease of usage, and biocompatibility. Therefore, this work reports on the use of hexahydrate ferric chloride and nerium oleander flower extract to synthesize nanoscaled hematite (α-Fe2O3) iron oxide particles conjugated with various drugs for antibacterial agents. Diverse morphological, physicochemical, structural, optical, and magnetic characteristics have been characterized using FESEM, EDX, XRD, UV–vis, FTIR, Raman and vibrating sample magnetometer. The synthesis of the polyshaped iron oxide nanoparticles, with average sizes ranging from 47.2 ± 20 nm, was accomplished. Furthermore, temperature-dependent variations in magnetic behavior were observed during calcination. The XRD and Raman spectra revealed hematite (α-Fe2O3) type formation of iron oxide nanoparticles. Only calcinated IO-NPs at high temperatures (700 °C) demonstrated low coercivity and residual magnetism, which revealed weak ferromagnetic ordering; other calcinated samples, including nascent ones, showed incredibly weak ferromagnetic ordering. Besides, the effectiveness of drug-encapsulated iron oxide nanoparticles against bacteria in vitro was examined. It was interesting to observe that gentamycin-coated IO-NPs tended to be more susceptible to S. aureus than E. coli bacteria, but streptomycin-conjugated IO-NPs showed the reverse trend. However, as compared to the nascent sample and the high temperature (700 °C) calcinated sample, both antibiotic-loaded IO-NPs displayed better inhibitory abilities.

Insight into the roles of hematite iron oxide nanoparticles on microalgae growth, urban wastewater treatment and bioproducts generation: Gompertz simulation, nutrient mass balance and gene expression

In this study, the effect of α-Fe2O3 nanoparticles spiking in urban wastewater (UWW) on growth rate, wastewater treatment ability and bioproducts generation of C. vulgaris and Spirulina was investigated and compared with pure cultivation system. The biomass concentration of C. vulgaris and Spirulina improved by 20 % and 39 % at 10 and 15 mg/L α-Fe2O3, respectively while the both microalgae growth pattern fitted better with Gompertz simulation after treatment with α-Fe2O3. The nutrients mass balance revealed that 1 g of treated C. vulgaris and Spirulina could uptake more COD, TN and TP in comparison to the untreated cells. The lipid generation increased remarkably (C. vulgaris: 45 % and Spirulina: 72 %) after α-Fe2O3 treatment. While, the addition of α-Fe2O3 showed no significant impact on the protein and carbohydrate productivity. Overall, this study evangelize the role of nanoparticles on promoting microalgae applications as a sustainable approach for UWW treatment and promising feedstock for biofuel production.

Electroactivity of the magnetotactic bacteria Magnetospirillum magneticum AMB-1 and Magnetospirillum gryphiswaldense MSR-1

Magnetotactic bacteria reside in sediments and stratified water columns. They are named after their ability to synthesize internal magnetic particles that allow them to align and swim along the Earth’s magnetic field lines. Here, we show that two magnetotactic species, Magnetospirillum magneticum strain AMB-1 and Magnetospirillum gryphiswaldense strain MSR-1, are electroactive. Both M. magneticum and M. gryphiswaldense were able to generate current in microbial fuel cells with maximum power densities of 27 and 11 µW/m2, respectively. In the presence of the electron shuttle resazurin both species were able to reduce the crystalline iron oxide hematite (Fe2O3). In addition, M. magneticum could reduce poorly crystalline iron oxide (FeOOH). Our study adds M. magneticum and M. gryphiswaldense to the growing list of known electroactive bacteria, and implies that electroactivity might be common for bacteria within the Magnetospirillum genus.

Design of hydrophobic polyurethane–magnetite iron oxide-titanium dioxide nanocomposites for oil-water separation

Efficacious oil-water separation has become a global challenge owing to regular oil spillage accidents and escalating industrial oily wastewater. In this study, we synthesized titanium dioxide and magnetite iron oxide nanoparticles to use as a precursor for the production of the nanocomposites. Hydrophobic nanocomposites were fabricated using polyurethane, hematite and magnetite iron oxide nanoparticles, and titanium dioxide nanoparticles through a sol-gel process. The formation of the obtained nanocomposites was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analyses. In addition, the thermogravimetric and differential thermogravimetric (TGA/DTG) and BET surface area results exhibited enhanced thermal stability of the optimized nanocomposite which displayed mesoporous type materials feature with high porosity. Furthermore, the obtained outcomes demonstrated that the distribution of nanoparticles into a polymer matrix had a significant impact on enhancing superhydrophobicity and the separation efficiency against sunflower oil. Seeing the water contact angle of the nanocomposite-coated filter paper was about 157° compared to 0° for the uncoated filter paper and endowed separation efficiency of almost 90% for 5 consecutive cycles. Thereby, these nanocomposites could be an ideal candidate for self-cleaning surfaces and oil-polluted water purification.

Variation of Polietilena Glikol (PEG) Volume Ratio Addition to the Extraction and Synthesis of Hematite (Fe2O3) from Iron Ore of Pemalogan Village using the Precipitation Methods

The synthesis of hematite iron oxide from iron ore in Pemalongan village was carried out using an easy and simple method, namely precipitation. The purpose of this study was to determine the extraction results, crystal structure and crystal size of the compounds synthesized using the precipitation method. Iron ore processing is carried out by reacting 37% (w/w) HCl by dripping 25% (v/v) NH4OH as a precipitating agent and adding PEG-200 to control particle size by varying the volume ratio of PEG-200: Iron 1:5 ( mL/g), 2:5 (mL/g), and 3:5 (mL/g). Then calcined at 500°C for 2 hours. The synthesis results were characterized using Xray diffraction (XRD) and scanning electron microscopy (SEM). The results of XRD analysis with varying volume ratios of PEG-200:iron 1:5 (mL/g), 2:5 (mL/g), and 3:5 (mL/g) have formed a hematite iron oxide phase. The synthesis results with a volume ratio of 1:5 (mL/g) produced the highest purity and had a trigonal geometric structure, cell parameters a = 5.036340 Å; b = 5.036340 Å; and c = 13.345420 Å; α = β = 90˚; γ = 120˚ and the space group is R3 c. Calculation of crystal size using the Debye Scherrer equation results in variations in the volume ratio of PEG-200: Iron 1:5 (mL/g), 2:5 (mL/g), and 3:5 (mL/g) is 50.9912 nm; 43.08837 nm; and 45.30663 nm. The SEM characterization results showed that the iron oxide hematite produced from the synthesis clumped and formed small non-uniform grains.

The Influence of Different Hematite (α-Fe2O3) Particles on the Thermal, Optical, Mechanical, and Barrier Properties of LDPE/Hematite Composites.

There is an increasing need to develop new polymer composites with improved properties compared to conventional pure polymer materials. This work aims to develop composites of low-density polyethylene (LDPE) and iron oxide hematite particles. For this purpose, different types of hematite particles with well-defined shapes and narrow size distributions were synthesized: HC2 sample with pseudocubic hematite particles of an average diameter of 1020 nm, HE1 sample with ellipsoidal hematite particles of an average diameter of 533 nm, and HS1 sample with spherical hematite particles of an average diameter of 168 nm. The mass fractions of hematite in the composites were 0.25%, 0.5%, and 1%. Prepared LDPE/hematite composites were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and diffuse reflectance ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. The mechanical and barrier properties were also studied. The obtained results showed that all prepared composites have improved properties compared to the pure LDPE, especially the composites with pseudocubic hematite particles of well-defined shapes. The results of this study indicate that LDPE/hematite composites can be promising materials for a wide range of applications, especially as packaging materials where improved thermal and mechanical properties as well as resistance to ultraviolet (UV) irradiation are required.

Environmental implications of interaction between humic substances and iron oxide nanoparticles: A review.

Goethite, hematite, ferrihydrite, and other iron oxides bind through various sorption reactions with humic substances (HS) in soils creating nano-, micro-, and macro-aggregates with a specific nature and stability. Long residence times of soil organic matter (SOM) have been attributed to iron-humic substance (Fe-HS) complexes due to physical protection and chemical stabilization at the organic-mineral interface. Humic acids (HA) and fulvic acids (FA) contain many acidic functional groups that interact with Fe oxides through different mechanisms. Due to the numerous interactions between mineral Fe and natural SOM, much research has led into a better identification and definition of HS. In this review, we first focus on the surface colloidal properties of Fe oxides and their reactivity toward HS. These minerals can be efficiently identified by usual techniques, such as XRD, FTIR spectroscopy, XAS, Mössbauer, diffuse reflectance spectroscopies (DRS), HRTEM, ATM, NanoSIMS. Second, we present the recent state of art regarding the adsorption/precipitation of HS onto iron mineral surfaces and their effects on binding metalloid and trace elements. Finally, we consider future research directions based on recent scientific literature, with particular focus on the ability of Fe nano-particles to increase Fe bioavailability, improve carbon sequestration, reduce greenhouse gas emissions, and decrease the impact of persistent organic and inorganic pollutants. The methodology in this field has rapidly developed over the last decade. However, new procedures to estimate the nature of Fe-HA bonds will be important contributions in clarifying the role of natural iron oxides in soil for carbon stabilization.

A Facile Method for the Preparation of α-Fe2O3/Reduced Graphene Oxides Nanocomposites as Electrode Materials for High Performance Supercapacitors

In this work, a low-cost, fast, and environmental friendly microwave assisted chemical route to prepare hematite iron oxide (α-Fe2O3) nanoparticles/reduced graphene oxides (RGO) nanocomposites and their potential use as electrodes for the supercapacitors was presented. The x-ray diffraction (XRD), Raman, FESEM and high resolution transmission electron microscopy (HR-TEM) studies confirmed that the prepared nanostructures have pure rhombohedral symmetry of Fe2O3 with hematite phase and high crystallinity. Morphological features obtained from Field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) analyses showed that the α-Fe2O3 nanoparticles possessed spherical shaped particles with size ranging from 10–20 nm, and the nanoparticles of α-Fe2O3 were found to be anchored on the surface of RGO sheets. Electrochemical studies were carried out using α-Fe2O3 nanoparticles and α-Fe2O3/RGO nanocomposites electrodes and their performances were compared. It was observed that that α-Fe2O3/RGO nanocomposites electrodes displayed higher specific capacitance of 356 F g−1 measured at a scan rate of 50 mV s−1, while, α-Fe2O3 nanoparticles showed a specific capacitance of 123 F g−1 at a similar scan rate. Furthermore, α-Fe2O3/RGO nanocomposites exhibited excellent cyclic stability for 2500 cycles measured at a scan rate of 50 mV s−1 with ~92% capacitance retention. The presented approach is promising for the mass production of high performance electrodes applied in energy storage device.

Synthesis of Magnetic Iron Oxide Fe3O4/α-Fe2O3 for the Adsorptive Removal of Cadmium from Aqueous Solution

Magnetic iron oxide nanoparticles were successfully synthesized by co-precipitation method. The magnetite and mixture of magnetite/ hematite iron oxide were obtained and characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption/desorption isotherms and vibrating sample magnetometer. These nanoparticles exhibited good adsorbents performance for removal cadmium metal ion. The mixture of magnetite/ hematite particles showed small size of particle and removed cadmium ion rapidly. The rates of Cd removal were 90 and 95% with Fe3O4 and Fe3O4/α-Fe2O3 samples respectively and the pseudo first and second kinetic models were applied to describe adsorption. Langmuir and Freundlich models were used for describing adsorption isotherms.

Studying the potential of rock magnetism to distinguish combustion structures of different type

Rock magnetism has a significant potential to elucidate archaeological issues related to firing process owing to the strong dependence of clay magnetic properties on firing conditions. The present study is an attempt to characterize some basic fuel installations (hearths, household ovens, pottery kilns, kilns for building ceramics and metallurgical ovens) by the most common magnetic parameters (magnetic remanence, initial magnetic susceptibility, Koenigsberger ratio, frequency-dependent magnetic susceptibility and viscosity coefficient), accumulating a set of relevant magnetic data for exemplary structures. Rasmussen method was used for firing temperature determinations.It is concluded that household ovens, used for cooking/heating activities only, were fired at temperatures below 500 °C. The acquired thermoremanence is in most cases partial TRM, generally less than 800 mA/m, the measured magnetic susceptibility does not exceed 300× 10−8m3/kg, and the corresponding Q ratios are mostly below 10. Experimentally baked clays show that already a firing at temperatures slightly above 500 °C yield much stronger and more stable TRM, and higher χ and Q ratio. Hearth and pottery kilns appear indistinguishable at this research stage, but systematically higher Q ratios were observed for the pottery kilns. Rising the temperature in the kilns for building ceramics and metallurgical ovens causes formation of a higher proportion of coarse-grained hematite and epsilon iron oxide, resulting in thermoremanence increase and magnetic susceptibility decrease.Firing temperatures determined for the household ovens corroborate well the observed magnetic parameters indicating a maximum operating temperature of not more than 460–470 °C. On the other hand, they appear to be underestimated when the highest firing intensity was expected (at T > 900 °C). This is indicative that further studies in this aspect are needed. The slags studied fail to produce any feasible result in terms of their firing temperatures, probably because of their strong inhomogeneity and/or complicated firing history. There is an excellent agreement between the estimated temperatures for clays baked in an experimental dual chamber kiln and the thermocouple readings. Differences in firing atmosphere between archaeological structures (or their experimental analogues) and laboratory furnaces probably have the least effect on low-temperature heated objects (i.e., household ovens) and the strongest on high-temperature ones where reducing conditions dominate that should be taken into account in the data interpretation. An overestimation of Tfiring can happen for low-temperature materials due to possible intense magnetic transformations above 600 °C.

Conductivity improvement of magnetite and hematite nanoparticles via admicellar polymerization of polypyrrole

Polypyrrole (PPy) was used to obtain a coating on magnetite (Fe3O4) and hematite (Fe2O3) iron oxide nanoparticles (IONPs). PPy was synthesized on the surface of IONPs by admicellar polymerization for enhancement of electrical conductivity. Low surfactant and monomer levels enabled formation of films on the order of 1 nm thickness. The hydrophobic tendency of the modified IONPs was observed by aggregation in water and exclusion of water molecules. Coated IONPs were characterized by Fourier transform infrared spectroscopic techniques (FT-IR) and scanning electron microscopy (SEM) with particle size distribution analyzed by dynamic light scattering (DLS). Thermal stability of PPy-coated IONPs was investigated by thermogravimetric analysis (TGA). Lastly the magneticity and electrical conductivity of the modified IONPs were analyzed by VSM and multimeter measurements of packed IONPs in a circuit, respectively. Modified IONPs significantly enhanced electrical conductivity with greater effect related to the amount of PPy film coated on the IONP surface. Particle sizes of magnetite and hematite were found within the range between 50 and 2000 nm, depending upon PPy coating. The electrical property was successfully improved, but magnetic properties werenotstatisticallydifferentfrom the bare IONPs. The concentration of Py monomer at 30 mM shown as the critical concentration of both magnetite and hematite had the achievement of the high electrical conductivity.

Study on the Color Genesis of South Red Agate and the Geological Characteristics of the Siliceous Gravel Layer

The aim of the study was to explore the gem mineralogical characteristics of southern red agate and then analyze its structural characteristics and color causes. The mineral composition, structure, and chromogenic minerals of Nanhong agate were tested by a conventional gemmological test and observed under the microscope, infrared spectrum, and microlaser Raman spectrum. It is found that the color of southern red agate samples is mainly dark red or orange red, and colorless, white or yellow bands can be seen in some samples; the relative density is in the range of 2.59∼2.65. The matrix structure of the sample is mainly long fiber and short fiber, and some of them are fine-grained and crystalline plasmid. There are concentric ring-banded structures, and some horizontal banded and vein structures can also be seen. The analysis and test results show that the south red agate has a typical radial fiber structure, and the main chemical component is SiO2; Under the orthogonal polarizing microscope, a large number of round reddish brown mineral inclusions with banded distribution can be seen, the spot-colored mineral is iron oxide hematite, and calcite of the late hydrothermal origin can be seen in the cracks. In addition, the study shows that the formation of south red agate is multistage and the formation of hematite inclusions is also multistage.

Magnon transport in the presence of antisymmetric exchange in a weak antiferromagnet

The Dzyaloshinskii-Moriya interaction (DMI) is at the heart of many modern developments in the research field of spintronics. DMI is known to generate noncollinear magnetic textures, and can take two forms in antiferromagnets: homogeneous or inter-sublattice, leading to small, canted moments and inhomogeneous or intra-sublattice, leading to formation of chiral structures. In this work, we first determine the strength of the effective field created by the DMI, using SQUID based magnetometry and transport measurements, in thin films of the antiferromagnetic iron oxide hematite, α-Fe2O3. We demonstrate that DMI additionally introduces reconfigurability in the long distance magnon transport in these films under different orientations of a magnetic field. This arises as a hysteresis centred around the easy-axis direction for an external field rotated in opposing directions whose width decreases with increasing magnetic field as the Zeeman energy competes with the effective field created by the DMI.

Removal of copper ions from wastewater via adsorption on modified hematite (α-Fe2O3) iron oxide coated sand

In this study, we improved the surface quality of synthetic hematite (α-Fe2O3) iron oxide coated sand (HIOCS) and its adsorption and desorption capabilities for copper ions in aqueous solutions, and we evaluated the iron oxide content on the sand surface. We prepared three different control pH (1, 5, and 10) solutions using FeCl3, to obtain the above results. In addition, we used X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and EDX, analyses were performed for characterization of analysis to characterize the surface morphologies of the coated layer and observe copper ion adsorption on the coated sand surfaces. Batch experiments were conducted to assess copper ion adsorption under specific parameters, such as the influence of time, dosage, pH, and initial copper concentration. Adsorption isotherms and kinetics models were used to fit the experimental data at various temperatures (287, 297, and 307 K), and different desorption media were studied to assess copper ion regeneration from hematite (α-Fe2O3) iron oxide coated sand (HIOCS). We observed high intensity, pure hematite (α-Fe2O3) crystal peaks, and iron content (105.3 mg/g) on the sand coated at a pH of 1, and copper ion removal efficiency was more effective (94%) at lower pH, compared to the sand coated at a pH 5 and 10 (81% and 84%, respectively) at constant parameters (pH of 6, dose of 4 g/L, temperature of 297 K, 30 mg/L of Cu2+ concentration, and contact time of 180 min). The Langmuir isotherms model (R2 = 0.991) and pseudo-second-order kinetic models (R2 = 0.978) were found to correlate better than the Freundlich isotherm model (R2 = 0.966), or the pseudo-first-order kinetics model (R2 = 0.965). We achieved the highest Cu2+ adsorption of qm = 3.93 mg/g, as obtained from the Langmuir isotherms. We also observed that acidic (HCl and H2SO4) solutions were the best desorption media for copper ions on the surface of hematite (α-Fe2O3) iron oxide coated sand (HIOCS). Thus, this study found that copper ions can be removed through an environmentally friendly process using low-cost hematite (α-Fe2O3) iron oxide coated sand (HIOCS), under suitable conditions.

Quartz and Hematite Activation by Zn, Ca and Mg Ions in the Cationic Flotation Route for Oxidized Zinc Ore

ABSTRACT Anionic, cationic and cationic/anionic flotation is widely used in the concentration process for low-grade oxidized zinc ores. In the cationic flotation route, sodium silicate is used as a depressant for gangue minerals and amine as a collector for zinc minerals previously activated by sodium sulfide. However, the presence of polyvalent ions in aqueous solution can affect the surface properties of the various minerals and consequently, the selectivity of the process. This study evaluated the effect of Zn, Ca, and Mg ions, originated by the solubility of smithsonite and dolomite, on the surface properties of quartz and hematite. Microflotation tests showed the inefficiency of sodium silicate as a depressant for quartz in aqueous solution even when Zn, Ca, and Mg ions were not present. Activation of hematite by Zn ions was observed, impeding the separation of smithsonite and hematite (iron oxide). Results obtained from the microflotation and zeta potential tests were analyzed based on the speciation diagrams of the reagents and ions studied, as well as published studies.

Effect of nanoparticles of feldspar and hematite using different levels of chemical potassium fertilizer on yield and protein production of wheat

The study was conducted to investigate the wheat yield affected by different concentrations of chemical Potassium (K) (0, 25%= 28.6, 75%= 85.7 and 100%= 118.0 kg Kha −1 recommended rate, KRR), with and without the application of foliar spraying of feldspar nanoparticles solution and different iron treatments (using foliar spraying of 0.3% twice from ferrous sulphate, or natural hematite nanoparticles). Two field experiments were conducted at two different locations; the first was at the Agricultural farm of Sids Agricultural Research Station (ARC), and the second was at a private farm at Sids village in 2018/2019 season. Grain, straw and biological yields, nitrogen content, protein content, and protein yield were determined. Results showed that increasing K levels up to 118.0 kg Kha −1 increased grain, straw, biological yields nitrogen, protein content, and protein yield. Foliar spraying of feldspar nanoparticles or ferrous sulphate or hematite nanoparticles enhanced all the above-mentioned parameters. Combined 75% KRR with feldspar nanoparticles showed yields and quality of wheat equal to those under 100% KRR. Foliar spraying of hematite nanoparticles has equal effect on wheat productivity as ferrous sulphate. The highest wheat yields and protein characteristics were achieved for the treatment of 100% KRR or 75% KRR with foliar spraying of feldspar nanoparticles and foliar spraying of ferrous sulphate or hematite nanoparticles. To conclude; the study revealed the possibility of saving about 25% KRR by foliar spraying of natural feldspar nanoparticles, and using hematite (iron oxide) nanoparticles instead of ferrous sulphate.

Petrographic and isotopic studies in Kamoo area, northeast isfahan, Iran

The study area is located 5.5 km north-east of Kamo County and 30 km north-east of Meymeh, Isfahan. Kamo Index comprises an anticline with a northwest-southeast trend, the outcrop of which consists of siltstone-sandstone and Jurassic shale rocks that lie along a cretaceous unit. Based on field studies as well as petrographic and geochemical investigations, mineral assemblages and minerals in the area include chalcopyrite, pyrite, marcasite, and magnetite as primary ores and malachite, bornite, covellite, chalcocite, hematite, goethite, and hydrous iron oxides as secondary ores. The secondary ores have been formed by oxidation and biogenic processes. The primary textures are granular, disseminated, vein-shaped, and layered and the secondary textures are boxed and martitized, shear zones, replacements, and veins. Tectonic, metamorphic, and oxidation factors are involved in the formation of these textures. Due to tectonic activity in this area and the presence of faults, replacement, vein, and shear textures, which have developed after mineralization, are observed. Among alterations, hematite, propylitic, sericitic, limonitic, and kaolinitic are highly prevalent and they are important in the formation of iron deposits. The sub-alkaline granitoids of the region are related to the continental subduction-zone orogenic series. Studies on the decomposed iron samples from Kamo show that most of the samples are in the sub-alkaline series and the chemical and mineralogical composition of the magma derived from this series is calc-alkaline with a large amount of iron. According to mineralogical, lithological, and geochemical evidence and based on isotopic results, Kamo deposit is a skarn-type deposit.

A Synthetic Haematite Reference Material for LA‐ICP‐MS U‐Pb Geochronology and Application to Iron Oxide‐Cu‐Au Systems

In both nature and synthetic experiments, the common iron oxide haematite (α‐Fe2O3) can incorporate significant amounts of U into its crystal structure and retain radiogenic Pb over geological time. Haematite is a ubiquitous component of many ore deposit types and, therefore, represents a valuable hydrothermal mineral geochronometer, allowing direct constraints to be placed on the timing of ore formation and upgrading. However, to date, no suitable natural haematite reference material has been identified. Here, a synthetic haematite U‐Pb reference material (MR‐HFO) is characterised using LA‐ICP‐MS and ID‐TIMS. Centimetre‐scale ‘chips’ of synthesised α‐Fe2O3 were randomly microsampled via laser ablation‐extraction and analysed using ID‐TIMS. Reproducible U/Pb and Pb/Pb measurements were obtained across four separate chips (n = 13). Subsequently, an evaluation of the suitability MR‐HFO in constraining U‐Pb data via LA‐ICP‐MS is presented using a selection of natural samples ranging from Cenozoic to Proterozoic in age. The MR‐HFO normalised U‐Pb ratios are more concordant and ages more accurate versus the same LA‐ICP‐MS spot analyses normalised to zircon reference material, when compared with independently acquired ID‐TIMS data from the same natural haematite grains. Results establish MR‐HFO as a suitable reference material for LA‐ICP‐MS haematite U‐Pb geochronology.