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The "New Journal of Chemistry" published by the Royal Society of Chemistry features a variety of research papers on topics such as bioelectrocatalysis, photovoltaic properties, and electrochemical studies. The journal aims to connect the global chemistry community through high-impact publications and training courses. The articles cover a range of subjects, including the synthesis of materials for energy applications, catalysis, and optical properties of compounds. [Extracted from the article]

Insufficient surface dynamics and severe carrier recombination limit the photoelectrochemical water splitting (PEC-WS) performance of hematite (α-Fe2O3) photoanodes. The surface/interface engineering as an effective method can improve the above-mentioned problems. In this study, the ZIF-67 and FeCoNi-LDH as cocatalysts formed via in situ hydrolysis are successfully introduced on the surface of the α-Fe2O3 photoanode to improve the photogenerated carrier transport. The Sn@α-Fe2O3/ZIF-67/FeCoNi-LDH photoanode exhibits an excellent photocurrent density of 1.72 mA cm−2 at 1.23 VRHE, which is 1.7 times that of the original α-Fe2O3 photoanode. The detailed studies demonstrate that the introduced ZIF-67/FeCoNi-LDH heterojunction cocatalyst provides more abundant surface active sites and defects and enhances the light absorbance ability and electric conductivity. The synergistic effect between ZIF-67 and FeCoNi-LDH cocatalysts can significantly enhance photogenerated carrier separation and transfer efficiency. [ABSTRACT FROM AUTHOR]

In this study, a feasible strategy, named hydrogen mineral phase transformation (HMPT) technology, is proposed and employed to achieve efficient and clean recovery of Hainan Shilu refractory iron ore (HSRIO). The influences of HMPT roasting temperature, roasting time, and H 2 concentration on the separation index of HSRIO are investigated. Under the optimal experimental conditions, the iron concentrate grade increases from 62.5% to 67.9%, and the iron recovery increases from 65.0% to 94.7% compared with the original beneficiation process. In addition, the evolution of mineral phases, magnetic properties, and mineral microstructures is analyzed using XRD, VSM, SEM, and high-temperature hot-stage microscopy. It is revealed that the transformation of hematite to magnetite occurs during the HMPT process, with the newly formed magnetite exhibiting a loose and porous reticulation structure. This study is of guiding significance for the development of Hainan Shilu refractory iron ore with high efficiency and zero-carbon emission. [Display omitted] • Efficient recovery of HSRIO achieved through environmentally friendly HMPT technology. • Precise phase control enhances mineral magnetism, thereby promoting iron ore recovery. • The reduction reaction of the mineral proceeds from the surface inward. • This study provides theoretical support for the industrial production of HMPT. [ABSTRACT FROM AUTHOR]

In polarizable materials, electronic charge carriers interact with the surrounding ions, leading to quasiparticle behavior. The resulting polarons play a central role in many materials properties including electrical transport, interaction with light, surface reactivity, and magnetoresistance, and polarons are typically investigated indirectly through these macroscopic characteristics. Here, noncontact atomic force microscopy (nc-AFM) is used to directly image polarons in Fe2O3 at the single quasiparticle limit. A combination of Kelvin probe force microscopy (KPFM) and kinetic Monte Carlo (KMC) simulations shows that the mobility of electron polarons can be markedly increased by Ti doping. Density functional theory (DFT) calculations indicate that a transition from polaronic to metastable free-carrier states can play a key role in migration of electron polarons. In contrast, hole polarons are significantly less mobile, and their hopping is hampered further by trapping centers. [ABSTRACT FROM AUTHOR]

The presence of thick (>100 m) and electrically conductive (< 10 Ω.m) ground cover is a major impediment in mineral exploration of deep resources. Iron-oxide copper gold (IOCG) systems in Australia are often associated with a pronounced potential field anomaly, depending on the oxidation state of iron, but the gravity and magnetic field signatures have little vertical resolution unless constrained by drill hole petrophysics. Additionally, IOCG systems have deep magmatic sources, with their conductivity anomalies extending at least to the lithospheric mantle. The Vulcan IOCG prospect lies about 30 km northeast of the Olympic Dam IOCG mine and is defined by a significant gravity anomaly associated with brecciated haematite beneath 850 m of sedimentary cover sequences. To image the physical properties and structural geometry of the Vulcan IOCG prospect, a 100-site broadband MT and passive seismic array was deployed in a 1 km grid over a 9 by 9 km area. Three-dimensional inversion of MT responses resolve structure in three distinct domains. Firstly, broad limestone-quartzite-shale stratigraphy (1–30 Ω.m) in the 850 m cover is delineated in resistivity and corresponds well with changes in shear-wave velocity. Secondly, the region of brecciated haematite below the cover sequences is shown to have lower resistivity (< 60 Ω.m) than surrounding country rock (> 100 Ω.m). Thirdly, a more electrically conductive (< 30 Ω.m) vertical zone that extends > 5 km is imaged a few kilometers to the northeast of the Vulcan haematite breccia, and appears to be linked by a region of low shear-wave velocity in the depth range 1–2 km. Two-dimensional inversion of more regional MT responses along a 200-km line passing through the Vulcan prospect suggest this vertical region of low resistivity links to the lower-crust with anomalous resistivity of < 60 Ω.m in a similar way as imaged beneath the Olympic Dam mine. It is suggested that this conductive region is associated with graphite precipitated from magmatically derived CO2-rich fluids cooling in a reducing environment. [ABSTRACT FROM AUTHOR]

Brazil's Fundão dam collapse is one of the world's largest disasters of tailing dam failures. Previous research has evaluated toxic metals and non-metals (Cd, Cr, Ni, Pb, As, Hg) in the same soil samples used in this study, and results have indicated that only Fe and Mn concentrations increased above the original baseline (Melo et al., 2023). Consequently, the present study's focus has shifted towards assessing and integrating changes in soil quality regarding chemical fertility and morphological, physical, and mineralogical attributes in the floodplains post-dam collapse. Soil samples from 0 to 0.2 and 0.2–0.4 m depths, and samples of Urochloa sp. were collected along ten transects, spanning 100 km perpendicular to the Doce River channel. This sampling strategy targeted specific landscape positions including areas affected by deposited iron tailings (DIT), soil tailing mixture (STM), and control soil (CS) devoid of iron tailing interference. Results showed no discernible alterations in Ca, Mg, K, and P concentrations in Urochloa sp., and the most severe negative impacts observed regarded the replacement of kaolinitic pre-disaster matrix for hematitic matrix, reduction in organic carbon, and the prevalence of sand and silt particles. These factors collectively contributed to triggering: (i) decrease in chemical fertility and cation exchange capacity and (ii) significant decline in physical quality, evidenced by increased density and reduced total porosity and macroporosity. Addressing these adverse effects would require the augment of organic matter levels and offset the dominance of the hematitic matrix in the DIT. Furthermore, it is imperative to decompact the DIT by mechanized or plant cultivation means. [ABSTRACT FROM AUTHOR]

Introduction: Soil organic matter plays an important role in the long-term "locking" of organic contaminants in soil environment. Recently, microbialderived organic matter have been recognized as essential components of stabilized soil carbon pools. However, the contribution of microbial-derived organic matter to sorption of organic contaminants remains unclear. Methods: Here, we obtained microbial-derived organic matter-mineral composites by inoculating model soil (a mixture of hematite and quartz sand (FQ) or montmorillonite and quartz sand (MQ)) with natural soil microorganisms and different substrate-carbon (glycine (G), glucose (P), or 2, 6-Dimethoxyphenol (B)), which were named GF, PF, BF, GM, BM, and PM, respectively. Batch sorption/ desorption experiments were conducted for phenanthrene (PHE) and ofloxacin (OFL) on the composites. Results and Discussion: The composites cultured with 2,6-dimethoxyphenol had the highest carbon content (0.98% on FQ and 2.11% on MQ) of the three carbon substrates. The carbon content of the composites incubated with MQ (0.64%-- 2.11%) was higher than that with FQ (0.24%--0.98%), indicating that montmorillonite facilitated the accumulation of microbial-derived organic matter owing to its large specific surface area. The sorption of PHE by microbial-derived organic matter was mainly dominated by hydrophobic partitioning and π-π conjugation, whereas the sorption of OFL was mainly dominated by hydrophobic hydrogen bonding and π-π conjugation. The sorption of OFL onto the composites was more stable than that of PHE. Microbial-derived organic matter -mineral composites can reduce the risk of organic contaminant migration in soil, particularly ionic organic contaminants. [ABSTRACT FROM AUTHOR]

The controlled synthesis of recyclable hematite in the leaching solution of secondary zinc oxide powder is an urgent problem in the chemical industry and metallurgy fields. In this paper, the effects of the temperature, agitation speed, and seed addition on the contents of iron, sulfur, potassium, sodium, and zinc in the iron removal residues, as well as the iron concentration in the supernatant after iron removal were systematically studied. In addition to the temperature control already reported, we found that the agitation speed can also control the transformation between jarosite and hematite phases. The content of jarosite in the residues can be effectively controlled by adjusting the agitation speed, thereby significantly improving the quality of hematite product, as indicated by SEM-EDS and XRD results. Under temperature of 185 °C, an agitation speed of 500 rpm, and a seed addition of 15 g/L, the iron, sulfur and zinc contents in the filter residues and the iron concentration in the supernatant were 59%, 3.22%, 0.92%, and 4.182 g/L, respectively. Kinetic studies show that the rapid oxidation kinetics is not conducive to the formation of high-quality hematite products. These results can directly guide the process of transformation of harmful jarosite into recyclable hematite from the leaching solution of secondary zinc oxide powder, which is of great practical significance for the controlled and waste-free removal of iron from aqueous solutions in the chemical industry and metallurgy fields. [ABSTRACT FROM AUTHOR]

Nanostructured iron (III) oxide was prepared by a facile hydrothermal method using poly(triazine imide) (PTI) as a sacrificial template. The physicochemical properties of pristine iron oxide and its analogue obtained in the presence of PTI confirmed strong effect of the latter as the morphology improving agent. Moreover, application of nitrogen rich semiconducting polymer during hydrothermal synthesis increased number of defects. The obtained sample was used as an electroactive additive for carbon‐paste electrode. PTI‐modified sample demonstrated 1.52 times higher oxidation current, and 1.39 lower charge transfer resistance compared to hematite obtained without PTI, as was confirmed by CV and EIS data. Therefore, it was proposed to use the as a sensor for the detection of gallic acid. The developed method showed excellent linearity within a concentration range of 67 nM to 17.7 µM with a detection limit equal to 44 nM and limit of quantification of 132 nM. Stablitity and reproducibility tests, as well as real sample analysis confirmed applicability of the proposed sensor for practical application. Excellent electrochemical properties of the submicron hematite particles are attributed to the developed lattice defects, which served as reaction centers and charge transducing points. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of iron oxide nanostructures, specifically snowflake architecture, are investigated for their potential applications in electrochemical sensing systems. A Raman spectroscopy analysis reveals phase diversity in the synthesized powders. The pH of the synthesis affects the formation of the hematite (α-Fe2O3) and goethite (α-FeOOH). Scanning electron microscopy (SEM) images confirm the distinct morphologies of the particles, which are selectively obtained through recrystallization during the elongated reaction time. An electrochemical analysis demonstrates the differing behaviors of the particles, with synthesis pH affecting the electrochemical activity and surface area differently for each shape. Cyclic voltammetry measurements reveal reversible dopamine detection processes, with snowflake iron oxide showing lower detection limits than a mixture of snowflakes and cube-like particles. This research contributes to understanding the relationship between iron oxide nanomaterials' structural, morphological, and electrochemical properties. It offers practical insights into their potential applications in sensor technology, particularly dopamine detection, with implications for biomedical and environmental monitoring. [ABSTRACT FROM AUTHOR]

A systematic study on the dissolution in concentrated alkali of two volcanic ashes from Cameroon, denoted as DAR and VN, is presented here. One volcanic ash, DAR, was 2 wt% richer in Fe and Ca and 4 wt% lower in Si than the other, designated as VN. Such natural raw materials are complex mixtures of aluminosilicate minerals (kaersutite, plagioclase, magnetite, diopside, thenardite, forsterite, hematite, and goethite) with a good proportion of amorphous phase (52 and 74 wt% for DAR and VN, respectively), which is more reactive than the crystalline phase in alkaline environments. Dissolution in NaOH + sodium silicate solution is the first step in the geopolymerisation process, which, after hardening at room temperature, results in solid and resistant building blocks. According to XRD, the VN finer ash powders showed a higher reactivity of Al-bearing soluble amorphous phases, releasing Al cations in NaOH, as indicated by IPC-MS. In general, dissolution in a strong alkaline environment did not seem to be affected by the NaOH concentration, provided that it was kept higher than 8 M, or by the powder size, remaining below 75 µm, while it was affected by time. However, in the time range studied, 1–120 min, the maximum element release was reached at about 100 min, when an equilibrium was reached. The hardened alkali activated materials show a good reticulation, as indicated by the low weight loss in water (10 wt%) when a hardening temperature of 25 °C was assumed. The same advantage was found for of the room-temperature consolidated specimens' mechanical performance in terms of resistance to compression (4–6 MPa). The study of the alkaline dissolution of volcanic ash is, therefore, an interesting way of predicting and optimising the reactivity of the phases of which it is composed, especially the amorphous ones. [ABSTRACT FROM AUTHOR]

Pure and Co (10 mol %)-doped α-Fe2O3 (Hematite) nanostructures have been effectively synthesized by hydrothermal method. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) have been used for the analysis of crystallography, morphology and functional groups of synthesized samples. The banding nature of synthesized samples is analyzed by Fourier transform infrared spectroscopy (FTIR). Powder XRD results reveal the formation of rhombohedral structured α-Fe2O3 nanostructures. Effect of dopant and synthesis conditions, such as precursor change and time duration of heating temperature has been investigated on the morphology of pure and Co (10 mol %)-doped α-Fe2O3 nanostructures. It has been observed that the addition of dopant, change of precursor and time duration of the heating temperature of hydrothermal treatment can effectively control the morphology of NPs. Methylene dye (MB) has been used as a test contaminant in aqueous solution to determine the photo-catalytic potential of Fe2O3 nanostructures under visible light. [ABSTRACT FROM AUTHOR]

This study focuses on the role of low-quality calcined Fanja (FNJ) clay in enhancing the behavior of cured cement mortar (CM) and its resistivity to chloride and sulfuric acid attack. Ordinary Portland cement was replaced with different quantities (10%, 25%, 35%, and 50% by weight) of FNJ, which was calcined at different temperatures (620 °C, 760 °C, and 900 °C). After 28 days of curing, all the hardened mortars were immersed in 5% sulfuric acid for up to 12 weeks. Additionally, a rapid chloride permeability test was conducted on the 91-day cured CM and CM-FNJ samples to evaluate the affinity of calcined FNJs to retard the chloride diffusion into CM. The results showed that all samples containing FNJ900 showed better physical and mechanical properties than the control sample, while CM with NFJ760 recorded nearly similar performance as CM-NFJ900. In contrast, the CM-FNJ620 mixtures showed lower properties than those of other mixtures. In addition to the pozzolanic reactivity of the calcined clay, the presence of hematite in the calcined clay strongly contributed to increasing the mechanical properties of the hardened mortar through forming calcium ferrosilicate hydrate binding phase, as confirmed by X-ray diffraction. Moreover, the existence of hematite increased the resistivity of CM against sulfuric acid attack as it acts as a buffer for an acidic medium. Compared with CM-FNJ900, the CM-FNJ760 is recommended for use as it exhibited a higher strength activity index and comparable resistance to accelerated chloride diffusion and sulfuric acid accompanied by lower energy demand and lower CO2 emission, achieving the concept of 'sustainability'. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) water splitting is pivotal for addressing the clean and renewable energy demands. However, developing low‐cost, efficient, and robust non‐precious metal catalysts for the acidic oxygen evolution reaction (OER) remains a significant challenge. In this study, we introduced Ce to modulate the electronic structure of Co3O4, enhancing the stability of Co3O4 without compromising its activity. Ce‐doped Co3O4 nanoparticles were electrodeposited onto Ti‐doped hematite surfaces (Ce : Co3O4/Fe2O3), significantly enhancing the PEC performance for water splitting under acidic conditions. These catalysts achieved high photocurrent densities and exhibited prolonged stability. Functioning as p‐type semiconductors, the Ce : Co3O4 nanoparticles not only boosted light absorption but also formed a p‐n heterojunction with the Ti‐doped hematite. This heterojunction generated a built‐in electric field that facilitated the separation and transfer of photogenerated carriers, thereby improving charge separation efficiency. Additionally, these nanoparticles expanded the active surface area of hematite and served as a co‐catalyst, markedly accelerating the OER kinetics. The Ce : Co3O4/Fe2O3 photoanode achieved an impressive photocurrent density of 1.08 mA cm−2 at 1.23 VRHE in acidic media, demonstrating its enhanced activity and stability. [ABSTRACT FROM AUTHOR]

Carbon fibers (CFs) are indispensable materials in our daily life. The excellent bearing capacity, remarkable dielectric property, ease of production, and corrosion resistance of CFRP composites distinguish them from all other options in addition to them, CFRPs may also shield from electromagnetic interference (EMI). In this study, two-layer CF reinforced epoxy composites reinforced with two different hematite (alpha- Fe2O3) and goethite (FeO(OH)) particle sizes of 50 nm and 45 μm (325 mesh) were produced using the manual lay-up method. Then, far field electromagnetic shielding effectiveness (SE) with 700 MHz - 6000 MHz range were examined. The maximum shielding effectiveness was determined to be at 5200 MHz with 39.28 dB for 5 wt.% FeO(OH), at 4700 MHz with 38.38 dB for 10 wt.% Fe2O3(325 mesh), at 3800 MHz with 37.15 dB for 15 wt.% Fe2O3(50 nm). [ABSTRACT FROM AUTHOR]

The Grotta d’Oriente, on the island of Favignana (Egadi, Sicily) has yielded a series of burials and human remains attributable to the final Epigravettian and Mesolithic. The Epigravettian burial, known as Oriente A, is characterised by funerary equipment consisting of perforated shells and a pebble with traces of red ochre. This site is one of the rare cases in which there is evidence of the use of ochre in a funerary context in Sicily and therefore the archaeological reconstruction requires the chemical-mineralogical characterization of this pigment using SEM, EDS, XRD, FORS and Raman spectroscopy. The comparative analysis of this pigment with a series of Terra Rossa from Favignana and other areas of Sicily has demonstrated that the Oriental A ochre does not derive from these sediments. This study shows the importance of applying different analysis methods for the characterization of ochres to try to define their origin. [ABSTRACT FROM AUTHOR]

Green synthesis of nanomaterials harnesses naturally occurring materials, including plant extracts, to offer environmentally friendly alternatives to conventional biomedicine, agriculture, and other field applications. This study explores the green route to Fe2O3 and cerium-doped Fe2O3 (Ce-doped Fe2O3) nanoparticles synthesized for the first time using the leaf extract of Platycladus orientalis. The synthesized nanoparticles were characterized for their structural, morphological, chemical, and optical properties. The hematite phase of Fe2O3 nanoparticles with spherical morphology was obtained. The introduction of Ce as a dopant into Fe2O3 increased the lattice strain of Ce-doped Fe2O3 nanoparticles (0.51%) compared to pristine Fe2O3 (0.46%) even though the size of both nanomaterials was similar. Compared to pristine Fe2O3 nanoparticles, Ce-doped Fe2O3 nanoparticles also demonstrated enhanced antimicrobial and antifungal activities against Escherichia coli, Enterococcus faecalis, Listeria monocytogenes, Penicillium chrysogenum, Aspergillus niger, and Mucor mucedo. The green-synthesized Ce-doped Fe2O3 nanoparticles possess potential for application in biomedical and environmental fields based on their relevance to human health and food safety, diversity in microbial characteristics, and potential for resistance to conventional treatments. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) have emerged as a class of highly promising materials for wastewater dye removal due to their unique properties. However, the existing body of research has primarily concentrated on the removal of organic dyes. To address this gap and contribute to advancements in water treatment technologies, this study investigates the efficacy of a zirconiumterephthalate-based MOF for the adsorptive removal of hematite, an inorganic dye, from aqueous environments. This investigation explored the influence of key parameters, including initial dye concentration, pH, adsorbent dosage, and adsorption temperature, on the adsorption capacity of NH2-UiO-66 for hematite. The findings revealed that elevated temperatures and initial dye concentrations promoted hematite adsorption onto NH2-UiO-66. Furthermore, the analysis of experimental data demonstrated concordance with the theoretical predictions of both the linearized Freundlich and Langmuir isotherm models. The study of kinetic models reveals that the pseudo-first-order model can adequately describe experimentally obtained data. The adsorption thermodynamic parameter ΔG0 was found to be approximately -3.70, -3.94, and -4.19 kJ.mol-1 at 298, 313, and 328 K, respectively. Furthermore, the ΔH0 and ΔS0 parameters were 5.15 kJ.mol-1 and 54.3 J.mol-1, respectively, indicating an endothermic adsorption mechanism. Further investigation found that the regeneration effectiveness is greater than 92% even after three adsorption cycles. [ABSTRACT FROM AUTHOR]

In this work, the random pore model (RPM) is utilized for the kinetic study of hematite reduction to Iron with CO. This can significantly contribute to the more effective design of reduction reactors in Iron production plants. Indeed, the developed RPM in this work employs a real pore size distribution (PSD) of the solid reactant, resulting in more realistic and accurate kinetic parameters. Accordingly, the kinetic parameters were calculated via RPM using the data from the reduction experiments of a highly porous pure hematite pellet. Validation of such kinetic parameters by different pure hematite and industrial pellets with various porous structures demonstrated RPM as the most comprehensive non-catalytic gas–solid reactions model. The activation energy obtained for the mentioned reaction was calculated at 25.5 kJ/mol. In addition, oxygen ions showed a mean diffusion coefficient of 1.18 × 10−16 m2/s for the industrial pellets through the Iron product layer. Furthermore, the importance of adjusting the CO–CO2 ratio on the conversion in the reduction reactor was discussed. The results of this work could help reduce the amount of required CO and CO2 product during the reduction of hematite to Iron. [ABSTRACT FROM AUTHOR]

The article describes synthesis of green‐mediated hematite nanoparticles (20–30 nm) using Polianthes tuberosa flower extract. Structural, microscopic, and magnetic studies confirm the synthesis of iron oxide nanoparticles of pure hematite phase. Spectroscopic techniques are employed to identify different electronic transitions and defect levels as well as to estimate the energy bandgap and Urbach energy. A correlation among the particle size, bandgap energy, and Urbach energy is noticed. These hematite nanoparticles act as visible light photocatalyst which degrade dye in aqueous medium without the addition of any additives. The catalyst particle size, catalyst quantity, pH of dye solution, and solution temperature have significant impact on the photodegradation process of dye molecules in aq. solution. All observations advocate that green synthesis of hematite nanoparticles with Polianthes tuberosa flower extract can significantly modulate their optical and photocatalytic properties. These materials may find potential uses in water splitting for hydrogen production and purification of water by removing organic pollutants. The study highlights that using commercially cheap starting materials and extract made from naturally available plant parts, materials having huge application potentials can be synthesized at low cost by the simple green synthesis approach. [ABSTRACT FROM AUTHOR]

A distinct layer of Ironic oolitic siltstone stratum is observed at the lower part of the Benxi Formation of the Middle Carboniferous in Liujiang Basin, exhibiting prominent lithological characteristics and consistent thickness within the region. According to the observation of rock thin sections and scanning electron microscopy, ironic oolites exhibit a diameter ranging from 0. 1 to 1. 0 mm, characterized by a ring structure with indistinct boundaries consisting of 3 to 5 layers enclosing fine quartz silt particles. According to the results of energy spectrum analysis, the oolite exhibits varying elemental compositions including Fe, Si, Al, O, K, C, and Ti in distinct regions. Through comprehensive analysis, it is determined that the predominant mineral constituents comprise limonite, hematite, quartz, and clay minerals. Through the analysis of trace elements, it is inferred that during the initial sedimentation of the Benxi Formation, the region was characterized by a relatively warm and semi-humid climate, a partially enclosed reducing environment bay, and brackish water conditions. After a prolonged period of weathering and erosion, the surface underwent deposition, resulting in a relatively enriched residual Fe element. Subsequently, through sedimentation and runoff processes, it was transported into the bay. The participation of organic carbon facilitated the formation of siderite (FeCO3) through its combination with Fe2O3. This resulted in the gradual deposition of siderite layers around suspended small quartz particles in the water body, which eventually settled on the seabed as particle concentration increased. Siderite undergoes diagenesis, leading to its instability and subsequent decomposition into Fe3O4. This process is further accompanied by oxidation, ultimately resulting in the transformation of siderite into limonite [FeO(OH)·H2O]. Additionally, under extremely arid and hot conditions during later stages, siderite readily oxidizes into hematite, thereby giving rise to the coexistence of limonite and hematite within irony ooids. [ABSTRACT FROM AUTHOR]

Basalt-hosted monocentric agates from Bou Hamza (Morocco) were examined to unravel a discrete relationship between moganite content, water content, and the abundance of various types of chalcedony/quartz microtextures, so that the agate-forming process is refined. Herein, moganite content is noticeably low in length-slow chalcedony (quartzine, up to 18 wt.%), as compared with the co-occurring length-fast (LF) chalcedony (up to 31 wt.%). Such a type of disparity reflects a stabilization of the crystallization front during the formation of chalcedonic bands. Recrystallization-related quartz types (i.e. feathery and mosaic/jigsaw puzzle) show low and high moganite content (0 and up to 34 wt.%, respectively) since they have likely originated from different silica precursors (i.e. opaline and chalcedonic, respectively). Meanwhile, the initial formation of mosaic quartz can be exclusively witnessed in the so-called zebraic variety of length-fast chalcedony (i.e. with twisted fibres) that should be hence regarded as a ,,metastable" variety of silica though. The range of total water content remains quite stable across chalcedonic bands (0.5–0.6 wt%) and reaches the highest values (0.7 wt%) in feathery quartz. However, there is rather a general negative relationship between the content of molecular water and silanol-group water. This can stem from the recycling of water species following the condensation reaction of silanols within the agate geodes. The agates originated from Fe-Ti-bearing solutions that co-precipitated goethite, hematite, and rutile, but also contain minor low-grade carbonaceous material. [ABSTRACT FROM AUTHOR]

ABSTRACT Sauce glazed wares of Yaozhou kilns are famous for their high gloss and distinctive glaze color palette varying from yellowish‐brown to reddish‐brown. In this work, sauce glazes were successfully replicated using the traditional technology of Yaozhou kilns. Micro‐Raman spectroscopy, combined with optical microscopy, scanning electron microscopy, x‐ray fluorescence, and reflective spectroscopy, was systematically applied to analyze the chemical composition, nature and distribution of crystals, and the coloration of the glazes. The results show that the yellowish‐brown glaze is mainly original from dendritic ε‐Fe2O3 crystals, whereas the reddish‐brown color is mainly derived from dendritic hematite crystals. Such dendritic structure could account for slightly color variations of the glaze surface observed in different angles, which also reported in Japanese Bizen ceramics. The principal component analysis (PCA) was further applied to study the Raman spectra of these iron oxides. The PCA results effectively indicates the structural disorders of these crystals introduced by ion substitutions. These substitutions could not only stabilize the crystals but also darken the crystals color. Besides, high Mg in the raw materials was found to benefit the growth of magnesioferrite crystals. The relative low level of Fe2O3, high level of SiO2, and CaO may relate to the formation of ε‐Fe2O3 crystals. [ABSTRACT FROM AUTHOR]

Hydrogen production by photoelectrochemical (PEC) water splitting is a sustainable means that can avert the effects of global warming caused by fossil fuels. For decades, a suitable semiconductor that can absorb solar radiation in the visible region has been a focal research question. Hematite has a theoretical Solar-To-Hydrogen efficiency of 15% which is higher than the 10% benchmark for PEC water splitting. Despite being cheap, chemically stable, and bearing a desired band gap, hematite has not reached this projection due to challenges like band edge mismatch, short hole diffusion length and charge recombination. Various articles have shown hetero-structuring is a reliable solution to some challenges due to enhanced spectral range, enhanced carrier mobility, strong built-in electric field and thus increase in efficiency. However, these articles lack scientific rationale on the performance of hematite and its hetero-structures on different substrates, which is the basis for this review. Our analysis suggests that hetero-structure improves hematite's PEC performance due to increased spectral range, enhanced carrier mobility and built-in electric field. This review article is organized as follows: a brief PEC background, performance parameters, Physical and Crystallographic properties of hematite, device configurations, performance of hematite and its hetero-structures on different substrates. [ABSTRACT FROM AUTHOR]

Chemical Oxygen Demand (COD), as a detection indicator of water pollution, is of particular importance in assessing organic pollution in water. Furthermore, accurate and simple measuring COD methods are essential for water quality assessment and pollution control. However, the photoelectrochemical oxygen demand (PECOD) measurement, as one of the measuring COD methods, is affected by the reaction of water splitting, which is one of the hindrances to the commercialization of the analytical method of the PeCOD measurement. Hence, to overcome this challenge, a new PANI/Ti:Fe2O3 photoanode is constructed by hydrothermal and photoelectrochemical (PEC) deposition methods and investigated their optical properties and photoactivity. Under optimization conditions, it is discovered that the oxidation of organic compounds produces a net steady‐state current (inet) is directly proportional to COD concentration, with a detection limit of 1 mM glucose solution and a wide linear detection range of 1–78.125 mM, which is suitable for high concentration of glucose detection. As has been noted, PANI/Ti:Fe2O3 photoanode overcomes the obstacles to the practical application and eventual commercialization of the PECOD technology. [ABSTRACT FROM AUTHOR]

Thermal decomposition of hematite plays an important role during pelletization and the iron fine‐based smelting processes such as HIsarna and flash shaft smelter. The temperature at which pure hematite decomposition occurs depends on the partial pressure of oxygen in the gaseous atmosphere. In the air, that is, at po2 = 0.21, the hematite decomposes at 1386 °C. In the present work, for an ore of a given composition, the effect of gangue on the thermal decomposition of hematite is experimentally determined using thermogravimetric analysis (TGA). A decomposition temperature of 1320 °C is found in the platinum crucible after analyzing the TGA curve. Thermodynamic calculations have been carried out using FactSage8.1 to investigate the effect of gangue on the stability of hematite. Thermodynamics calculations confirm that the hematite present in the ore decomposes at a lower temperature with the increase in the gangue content. Additionally, if gangue content can affect the temperature at which dissociation of hematite occurs, it is expected that the crucible material can also affect the dissociation. Interestingly most of the reported TGA experiments are performed either in alumina crucibles or it was not reported in the literature. Therefore, the effect of crucible materials, namely alumina and platinum, is also investigated. [ABSTRACT FROM AUTHOR]

Modifying photoanodes with metal-organic frameworks (MOFs) as oxygen evolution reaction (OER) cocatalysts has emerged as a promising approach to enhance the efficiency of photoelectrochemical (PEC) water oxidation. However, designing OER-active MOFs with both high photo- and electrochemical stability remains a challenge, limiting the advancement of this research. Herein, we present a facile method to fabricate a MOF-modified photoanode by directly loading a pentanuclear Co-based MOF (Co-MOF) onto the surface of a Ti-doped hematite photoanode (Ti:Fe2O3). The resulting Co-MOF/Ti:Fe2O3 modified photoanode exhibits an enhanced photocurrent density of 1.80 mA · cm-2 at 1.23 V, surpassing those of the Ti:Fe2O3 (1.53 mA · cm-2) and bare Fe2O3 (0.59 mA · cm-2) counterparts. Additionally, significant enhancements in charge injection and separation efficiencies, applied bias photon-to-current efficiency (ABPE), incident photon to current conversion efficiency (IPCE), and donor density (Nd) were observed. Notably, a minimal photocurrent decay of only 5% over 10 h demonstrates the extraordinary stability of the Co-MOF/Ti:Fe2O3 photoanode. This work highlights the efficacy of polynuclear Co-based MOFs as OER cocatalysts in designing efficient and stable photoanodes for PEC water splitting applications. [ABSTRACT FROM AUTHOR]

To realize the resource utilization of solid waste (coal slime) and further the dual carbon goals, utilizing coal slime and coal ash as adsorbates for CO2 capture is crucial. This study employed low-temperature N2 adsorption, low-pressure CO2 adsorption, X-ray diffraction, X-ray fluorescence, and isothermal adsorption tests to assess coal slime and coal ash's pore/mineral composition characteristics. Subsequently, the influence on CO2 adsorption was analyzed to reveal the CO2 adsorption mechanisms of pores and clay minerals, and CO2 molecule adsorption behavior. The results showed that: (1) ashing led to reductions in total pore volume, specific surface area, micropore volume, and micropore specific surface area, accompanied by substantial decreases in micropores and mesopores; (2) ashing generated high-temperature stable mineral species, including quartz, andalusite, hematite, and gypsum, while all calcite decomposed into CaO; (3) coal slime exhibited greater CO2 adsorption capacity than coal ash, influenced by pore structure and clay minerals; (4) the adsorption behavior of coal slime and coal ash likely aligns with micropore filling theory, suggesting CO2 is adsorbed within the 0.30–1.47 nm pore structure. This research contributes to optimizing coal by-product utilization in mining areas and exploring adsorbate materials for CO2 sequestration in abandoned goaf. [ABSTRACT FROM AUTHOR]

This report addresses the synthesis, characterisation, and photoelectrochemical performances of α-Fe2O3 nanorods decorated with g-C3N4. Photoanode composites were fabricated in a two-step procedure in which fluorine-doped tin oxide (FTO) glass was coated with α-Fe2O3 nanorods via a hydrothermal method, followed by incorporation of g-C3N4via a wet-impregnation method. In particular, the study investigates the effects of precursors of g-C3N4 (urea, dicyandiamide, and melamine) on the photoelectrochemical properties of the prepared α-Fe2O3/g-C3N4 films. The films were thoroughly analysed by means of X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area analysis, Fourier transform infrared (FTIR) spectroscopy, and UV-vis spectrometry. The highest photoelectrochemical output of the nanorod composite films was achieved with the use of g-C3N4 synthesized from urea, generating 15.3 μA cm−2 of photocurrent density as a result of better charge transfer driven by the formation of a semiconductor heterojunction. This is a staggering 12-fold improvement compared to the unmodified hematite nanorods which managed to only produce 1.2 μA cm−2 of photocurrent density. The merits of g-C3N4 prepared from urea as the best semiconductor couple for α-Fe2O3 are driven by its unique crystallinity and morphology with significantly larger surface area than g-C3N4 prepared from other precursors. The addition of glycerol as a sacrificial agent further improves the photocurrent to ca. 24 μA cm−2. The findings in this study show the potential of α-Fe2O3/g-C3N4 composites for sustainable photoelectrochemical hydrogen production. [ABSTRACT FROM AUTHOR]

Gem-quality amethyst at the La Manche deposit in the Avalon Zone of Newfoundland, Canada, occurs in a calcitegalena- barite-quartz vein adjacent to a historical lead mine containing similar mineralization. The deposit has produced mineral specimens as well as medium to medium-dark purple (up to 11 ct) and light purple (<3 ct) faceted stones. Amethyst is interpreted to have formed as the final stage of hydrothermal mineral deposition in the veins. Variable color, zoning, and crystal size in different but contiguous crystal-lined pockets suggest relatively closed-system behavior within pockets where amethyst/quartz was deposited from trapped silica- and iron-bearing hydrothermal fluid. Microthermometry of primary fluid inclusions revealed an average homogenization temperature of 75.5 ± 6.9°C, cooler than in fluid inclusions within sulfide-bearing zones of similar veins in the region. Average fluid salinity estimated from primary inclusions in amethyst, recorded in weight % NaCl equivalent, was 10.7 ± 1.8 eq. wt.% NaCl. This was similar to the salinity of fluid in sulfide-bearing veins in the region and significantly higher than in quartz-chlorite veins in the region. Secondary fluid inclusions suggest a late influx of lower-salinity fluids (7 eq. wt.% NaCl) associated with postcrystallization deformation that internally fractured amethyst crystals, reducing the volume suitable for faceting. Mineral inclusions are most abundant in the final purple and colorless growth stages in amethyst. They consist of black to red hematite spherulites, acicular "beetle-leg" inclusions (likely hematite), pyrite, chalcopyrite, and sprays of ochre goethite. Late iron-rich accessory mineral deposition may have depleted the hydrothermal fluid of iron, the chromophore in amethyst, during the final growth stage. La Manche amethyst's inclusion mineralogy is similar to that of amethyst from the deposits at Thunder Bay (Ontario, Canada), but the morphology of accessory sulfide minerals is different. [ABSTRACT FROM AUTHOR]

Iron (Fe) removal is a critical step in the hydrometallurgical zinc (Zn) extraction process. Hematite, a stable Fe precipitate, offers an environmentally friendly option that complies with environmental protection standards. While existing research primarily focuses on hematite process technology, there is a lack of studies on how ions in ZnSO4 leaching solutions affect Fe removal efficiency and hematite particle size distribution. This study investigated the influence of manganese II (Mn(II)) and magnesium II (Mg(II)) concentrations and temperature on both Fe removal efficiency and hematite particle size distribution in ZnSO4 leaching solution. The results indicated that at various temperatures, the highest Fe removal efficiency occurred with an initial Mn(II) concentration of 10 g/L and an Mg(II) concentration of 15 g/L. As the concentrations of Mn(II) and Mg(II) as well as temperature increased, FeSO₄ crystallization also increased, which adversely affected hematite precipitation. The average particle size of hematite decreases from 300 to 100 nm, resulting in a more uniform particle size distribution, which correlated with the homogeneous solution saturation precipitation mechanism. However, the number of rod-shaped, regular small particles decreases, while the number of irregular, blocky particles increased. [ABSTRACT FROM AUTHOR]

Three compositions Ni0.5Fe2.5O4, Ni0.7Fe2.3O4, and Fe2O3 were prepared by the co- precipitation method and checked by XDR, SEM, and VSM. The nanoparticles show a good match with the XRD standards. The particle sizes were 25, 32, and 18nm for the above compositions, respectively. The first composition showed the highest magnetization saturation. Suspensions containing the mentioned nanoparticles were prepared with two carrier fluids, distilled water, and dimethylsulphoxide (DMSO). A transmission to ultraviolet-visible light was tested and showed good transparency of more than 60 % in the red light region. The transparency to 623nm laser light under different magnetic fields of the six suspensions was tested. A simple device was fabricated to perform this test. The water suspension in water Ni0.5Fe2.5O4 has a larger variation in the transmitted power. The suspension of hematite shows no sensible change in the transmitted power. The magnetic properties of the nanoparticles and the dispersion property of the carrier fluid were behind the explanation of the suspension behaviours under the influence of the magnetic field. [ABSTRACT FROM AUTHOR]

The phase composition of the powder synthesized from aqueous solutions of sodium silicate Na2SiO3 and iron sulfate FeSO4 at the molar ratio Fe/Si = 2, as determined by x-ray diffraction (XRD) data, included hydrated sodium iron sulfate Na2Fe(SO4)2 · 4H2O and an x-ray amorphous product based on hydrated iron and silicon oxides. The phase composition of the powder obtained by fourfold washing of the synthesized powder in distilled water was represented by an x-ray amorphous product. Following firing in the air at temperatures ranging from 400 to 1200°C, hematite (Fe2O3) and cristobalite (SiO2) were identified in powder samples and the corresponding ceramics. Following firing at 900°C in graphite powder bedding, the phase composition of ceramic samples included magnetite (Fe3O4), laihunite (Fe4.74(SiO4)3), and fayalite (Fe2SiO4). The powder prepared from the product isolated from the mother liquor included hydrated sodium iron sulfate, Na2Fe(SO4)2 · 4H2O, and sodium iron sulfate hydroxide hydrate (metasideronatrite), Na4Fe2(SO4)4(OH)2 · 3H2O. Following heat treatment at 400°C, sodium iron sulfate (Na3Fe(SO4)3) was identified as the predominant phase in the powder. Powders resulting from the interaction of aqueous solutions of sodium silicate and iron sulfate can be used in the manufacture of high-temperature dyes and materials with magnetic properties, the creation of analogs of lunar or Martian regolith, as well as the development of functional (cathode) materials for Na-ion batteries. [ABSTRACT FROM AUTHOR]

Graphene and iron oxide nanocomposite materials attracted significant attention in different disciplines including optoelectronics, catalysis, and energy conversion/storage devices. Despite the extreme potential, a major obstacle had been the lack of effective and environmentally benign production techniques for mass-producing iron oxide-graphene nanocomposites. To overcome the obstacle, we opted for an efficient, facile, and eco-friendly hydrothermal synthesis route for the synthesis of iron oxide-graphene nanocomposites. The technique involved the homogenous mixing of metal salt precursor (iron chloride), and graphene oxide (GO) followed by a hydrothermal reaction under normal conditions. The synthesized nanocomposites were systematically investigated for structural, morphological, thermal, optical, and magnetic characteristics using XRD, Raman, SEM, TGA, UV–Vis, PL, and VSM techniques. The XRD and Raman studies confirmed the formation of α-Fe2O3-RGO and Fe3O4-RGO nanocomposites. The SEM images disclosed the anchoring of metal oxide nanoparticles to graphene nanosheets. The nanocomposite exhibited enhanced thermal stability compared to the pristine GO sample. The optical studies corroborated the better charge transfer response of nanocomposites and Hall effect measurements affirmed these nanocomposites as charge transport materials. The VSM measurements confirmed the magnetic behavior of the samples. Therefore, these nanocomposite materials could be a viable option for optoelectronics and energy conversion/storage devices. [ABSTRACT FROM AUTHOR]

Zebra rocks, characterized by their striking reddish‐brown stripes, rods, and spots of hematite (Fe‐oxide), showcase complex self‐organized patterns formed under far‐from‐equilibrium conditions. Despite their ease of recognition, the underlying mechanisms of pattern‐forming processes remain elusive. We introduce a novel advection‐dominated phase‐field model that effectively replicates the Liesegang‐like patterns observed in Zebra rocks. This numerical model leverages the concept of phase separation, a well‐established principle governing Liesegang phenomena in a two‐dimensional setting. Our findings reveal that initial solute concentration and fluid flow velocity are critical determinants in pattern morphologies. We quantitatively explain the spacing and width of a specific Liesegang‐like pattern category. Furthermore, the model demonstrates that vanishingly low initial concentrations promote the formation of oblique patterns, with inclination angles influenced by rock heterogeneity. Additionally, we establish a quantitative relationship between band thickness and geological parameters for orthogonal bands. This enables the characterization of critical geological parameters based solely on static patterns observed in Zebra rocks, providing valuable insights into their formation environments. The diverse patterns in Zebra rocks share similarities with morphologies observed on early Earth and Mars, such as banded iron formations and hematite spherules. Our model, therefore, offers a plausible explanation for the formation mechanisms of these patterns and presents a powerful tool for deciphering the geochemical environments of their origin. Plain Language Summary: Zebra rocks, known for their unique red and brown stripes and spots, hold clues to how similar patterns formed on early Earth and Mars. We have developed a new model to explain how these intriguing patterns form. The model suggests that the flow of fluids and the initial amount and location of dissolved iron‐oxide (rust) in water plays a big role in shaping the final Zebra rock design. The speed of the flow and the initial amount of rust can create different stripe and spot patterns, just like the ones in Zebra rocks. By studying these rocks, we can potentially decipher fluid flow scenarios of ancient environments on both Earth and Mars. Key Points: Patterns enable identification of flow velocity and concentration when observedFive Liesegang‐like patterns are replicated by varying flow velocities and initial concentrationsOne class of inclined patterns is identified in a very narrow flow velocity and low concentration regime [ABSTRACT FROM AUTHOR]

The total content, forms, and mineralogy of iron compounds in soils of forest-steppe, steppe, and semidesert zones of a large territory from the central chernozem regions to the Caspian lowland and from the Southern Urals to the Kerch Strait are studied. The study covers Chernozems (n = 40), Kastanozems (n = 15), Solonetzes (n = 7), and Calcisols (n = 7). Our results demonstrate the specific features in the distribution of total iron content, mass balance (τFe, Zr), forms of iron compounds, magnetic susceptibility (χ), and mineralogy in soil profiles. The distribution of τFe, Zr in the studied soils reflects the processes and conditions of soil formation, as well as specific lithological features. For a more comprehensive understanding of the transformation of iron compounds in steppe soils, particle-size fractions (<2, 2–5, 5–10, and 10–50 μm) have been analyzed by Mössbauer spectroscopy and magnetic susceptibility methods for Luvic Chernozem, Haplic Kastanozem, Haplic Kastanozem (Endosalic, Cambic), and Luvic Calcisol (Endosalic). In the clay fraction, a large share of Fe3+ is contained in highly dispersed oxides and hydroxides in a superparamagnetic state. In the humus-accumulative horizons of steppe soils, a decrease in the Fe2+ fraction in aluminosilicates caused by weathering is recorded. The observed correlation of the goethite/(hematite + goethite) ratio in humus-accumulative soil horizons with climatic parameters suggests the possibility to apply it for future paleoclimatic reconstructions. Mössbauer spectroscopy shows a significant increase in the content of nonsilicate iron in the humus-accumulative horizons of steppe soils as compared with the soil-forming material, which is an important confirmation for the formation of iron oxides during pedogenesis. A comparison of the methods for assaying nonsilicate iron in soils (Mössbauer spectroscopy and Mehra–Jackson extraction) demonstrates considerable differences in the results, suggesting that the chemical technique underestimates the amount of free iron forms. [ABSTRACT FROM AUTHOR]

Copyright of Environmental & Social Management Journal / Revista de Gestão Social e Ambiental is the property of Environmental & Social Management Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the present study, XRD, SEM/EDS, Raman, EMR/EPR spectroscopy, and vibrating sample magnetometry (VSM) were used to analyze the reduction of hematite by the carbonization products of waste activated sludge (WAS) at 500–1000 °C. The reduction process includes the following steps: α-Fe2O3 → Fe2O3 + Fe3O4 (Ttr~500 °C) → Fe3O4 (Ttr~600–700 °C) → FeO → Feamorph. (Ttr~1000 °C). The prevalence of certain phase compositions at different hematite reduction temperatures makes it possible to predict the areas viable for the application of reduced oxides: adsorbents (after Ttr~500 °C) → soft ferromagnetic materials (after Ttr~600–700 °C) → electrically engineered amorphous iron (after Ttr~1000 °C). [ABSTRACT FROM AUTHOR]

Solar redox flow batteries (SRFB) have attracted increasing interest for simultaneous capture and storage of solar energy by integrating a photoelectrochemical cell with a redox flow battery. Herein, a scalable, nanostructured α‐Fe2O3 photoanode exhibiting a high photovoltage of 0.68 V in a fully integrated Na4Fe(CN)6/AQDS SRFB is demonstrated. Thanks to its optimal band alignment, it uniquely enables stable, unassisted photocharging of the SRFB up to a state‐of‐charge (SOC) higher than 50%. Concurrently, its improved charge transfer results in a record unbiased photocurrent density of 0.22 mA cm−2, with a sixfold increase at zero SOC compared to α‐Fe2O3 film. Through an in‐depth optical and photoelectrochemical characterization of different α‐Fe2O3 morphologies, the impact of nanostructuring on charge transfer is quantified. Most interestingly, an increase in unbiased photocurrent is observed at 10% SOC (0.31 mA cm−2) and attributed to adsorption of ferricyanide, which enhances charge transfer. Importantly, it is demonstrated that the superior performance is retained after device scale‐up to 5.72 cm2. Overall, the demonstrated unassisted device is on par with previously reported dye‐sensitized solar cell‐assisted hematite‐based SRFBs. More broadly, this work contributes to the real‐world deployment of cost‐effective SRFBs based on Earth‐abundant materials. [ABSTRACT FROM AUTHOR]

The migration of arsenic in groundwater is influenced by the heterogeneity of the medium, and the presence of iron minerals adds complexity and uncertainty to this effect. In this study, a stratified heterogeneous sand column with an embedded hematite lens at the coarse-to-medium sand interface was designed. We introduced an arsenic-laden solution and controlled groundwater flow to investigate the spatiotemporal characteristics of arsenic migration and the impact of hematite dissolution. The results showed that the medium structure significantly influenced the arsenic migration and distribution within the lens-containing sand column. The clay layers directed the lateral migration of arsenic, and the arsenic concentrations in deeper layers were up to seven times greater than those on the surface. The extraction experiments of solid-phase arsenic revealed that the main adsorption modes on quartz sand surfaces were the specific adsorption (F2) and adsorption on weakly crystalline iron–aluminum oxides (F3), correlating to the specific and colloidal adsorption modes, respectively. Monitoring the total iron ions (Fe(aq)) revealed rapid increases within the first 14 days, reaching a maximum on day 15, and then gradually declining; these results indicate that hematite did not continuously dissolve. This study can aid in the prevention and control of arsenic contamination in groundwater. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hubei Minzu University (Natural Science Edition) is the property of Journal of Hubei Minzu University (Natural Sciences Edition) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Low temperature hydrothermal methods have been utilized to synthesize Hematite/Zinc oxide α‐Fe2O3/ZnO composite nano‐heterojunction nanorods grown on FTO glass substrates while monitoring the effect of different concentrations of urea on the morphology of the composite nano‐heterojunction. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used for the structural characterization of the α‐Fe2O3/ZnO different samples. UV‐visible spectroscopy was used for the characteristic absorbance versus wavelength of α‐Fe2O3/ZnO composite nano‐heterojunction which shows an absorption edge from 400 to 560 nm. X‐ray photoelectron spectroscopy (XPS) technique was applied to study of chemical composition of the α‐Fe2O3/ZnO and the obtained information demonstrated a pure phase α‐Fe2O3/ZnO has been achieved. The best efficiency among urea concentrations for the best composite nano‐heterojunction sample was achieved when using 0.2 M of urea. The electrochemical properties of the composite nano‐heterojunction were investigated using a three‐electrode electrochemical cell. Estimation of the electrochemical area shows that both the composite nano‐heterojunction and the bare α‐Fe2O3 have similar values. This confirms that the enhanced electrochemical property of the composite nano‐heterojunction is due to a synergetic effect as expected. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract This study focuses on the role of low-quality calcined Fanja (FNJ) clay in enhancing the behavior of cured cement mortar (CM) and its resistivity to chloride and sulfuric acid attack. Ordinary Portland cement was replaced with different quantities (10%, 25%, 35%, and 50% by weight) of FNJ, which was calcined at different temperatures (620 °C, 760 °C, and 900 °C). After 28 days of curing, all the hardened mortars were immersed in 5% sulfuric acid for up to 12 weeks. Additionally, a rapid chloride permeability test was conducted on the 91-day cured CM and CM-FNJ samples to evaluate the affinity of calcined FNJs to retard the chloride diffusion into CM. The results showed that all samples containing FNJ900 showed better physical and mechanical properties than the control sample, while CM with NFJ760 recorded nearly similar performance as CM-NFJ900. In contrast, the CM-FNJ620 mixtures showed lower properties than those of other mixtures. In addition to the pozzolanic reactivity of the calcined clay, the presence of hematite in the calcined clay strongly contributed to increasing the mechanical properties of the hardened mortar through forming calcium ferrosilicate hydrate binding phase, as confirmed by X-ray diffraction. Moreover, the existence of hematite increased the resistivity of CM against sulfuric acid attack as it acts as a buffer for an acidic medium. Compared with CM-FNJ900, the CM-FNJ760 is recommended for use as it exhibited a higher strength activity index and comparable resistance to accelerated chloride diffusion and sulfuric acid accompanied by lower energy demand and lower CO2 emission, achieving the concept of ‘sustainability’.

Abstract Green synthesis of nanomaterials harnesses naturally occurring materials, including plant extracts, to offer environmentally friendly alternatives to conventional biomedicine, agriculture, and other field applications. This study explores the green route to Fe2O3 and cerium-doped Fe2O3 (Ce-doped Fe2O3) nanoparticles synthesized for the first time using the leaf extract of Platycladus orientalis. The synthesized nanoparticles were characterized for their structural, morphological, chemical, and optical properties. The hematite phase of Fe2O3 nanoparticles with spherical morphology was obtained. The introduction of Ce as a dopant into Fe2O3 increased the lattice strain of Ce-doped Fe2O3 nanoparticles (0.51%) compared to pristine Fe2O3 (0.46%) even though the size of both nanomaterials was similar. Compared to pristine Fe2O3 nanoparticles, Ce-doped Fe2O3 nanoparticles also demonstrated enhanced antimicrobial and antifungal activities against Escherichia coli, Enterococcus faecalis, Listeria monocytogenes, Penicillium chrysogenum, Aspergillus niger, and Mucor mucedo. The green-synthesized Ce-doped Fe2O3 nanoparticles possess potential for application in biomedical and environmental fields based on their relevance to human health and food safety, diversity in microbial characteristics, and potential for resistance to conventional treatments.

Abstract Hydrogen production by photoelectrochemical (PEC) water splitting is a sustainable means that can avert the effects of global warming caused by fossil fuels. For decades, a suitable semiconductor that can absorb solar radiation in the visible region has been a focal research question. Hematite has a theoretical Solar-To-Hydrogen efficiency of 15% which is higher than the 10% benchmark for PEC water splitting. Despite being cheap, chemically stable, and bearing a desired band gap, hematite has not reached this projection due to challenges like band edge mismatch, short hole diffusion length and charge recombination. Various articles have shown hetero-structuring is a reliable solution to some challenges due to enhanced spectral range, enhanced carrier mobility, strong built-in electric field and thus increase in efficiency. However, these articles lack scientific rationale on the performance of hematite and its hetero-structures on different substrates, which is the basis for this review. Our analysis suggests that hetero-structure improves hematite’s PEC performance due to increased spectral range, enhanced carrier mobility and built-in electric field. This review article is organized as follows: a brief PEC background, performance parameters, Physical and Crystallographic properties of hematite, device configurations, performance of hematite and its hetero-structures on different substrates. Graphical Abstract

Aim of the study Eugenol, a phenolic compound commonly found in plants like clove and bay leaves, has garnered significant attention in the field of dentistry due to its diverse pharmacological properties. In dentistry, eugenol is frequently employed in various forms, such as in polymerized cement with zinc oxide for restorative purposes. Its applications extend to endodontic cements like zinc oxide-eugenol formulations, which are commonly used in dental procedures. So far, according to our knowledge, no study in the literature has approached formulations based on iron oxide nanoparticles and eugenol, this study being the first. Materials and methods In the present study, it was developed for the first time a formulation based on iron oxide nanoparticles obtained through the combustion method, embedded on its surface with eugenol. The prepared formulation was characterized through electron microscopy investigations, followed by further in vitro evaluation as concerned with their biosafety use on a healthy murine epidermal cell line. Results The results obtained showed that the naked iron oxide nanoparticles are biocompatible and safe to use on the healthy murine epidermal cell line, while the eugenol compound exhibits a dose-dependent cytotoxicity reaching until a value of ~17% at the highest tested dose (100 μg/mL). In addition, the cytotoxicity of eugenol decreased when this was embedded on the iron oxide nanoparticles surface, recording a value of 11% at the highest concentration tested. Conclusions In conclusion, the in vitro studies on such type of formulation in dentistry and dental medicine highlight their multifaceted applications of iron oxide nanoparticles as well as eugenol, emphasizing their potential for advancing dental treatments and diagnostics.

Mineral identification and quantification are key to the understanding and, hence, the capacity to predict material properties. The method of choice for mineral quantification is powder X-ray diffraction (XRD), generally using a Rietveld refinement approach. However, a successful Rietveld refinement requires preliminary identification of the phases that make up the sample. This is generally carried out manually, and this task becomes extremely long or virtually impossible in the case of very large datasets such as those from synchrotron X-ray diffraction computed tomography. To circumvent this issue, this article proposes a novel neural network (NN) method for automating phase identification and quantification. An XRD pattern calculation code was used to generate large datasets of synthetic data that are used to train the NN. This approach offers significant advantages, including the ability to construct databases with a substantial number of XRD patterns and the introduction of extensive variability into these patterns. To enhance the performance of the NN, a specifically designed loss function for proportion inference was employed during the training process, offering improved efficiency and stability compared with traditional functions. The NN, trained exclusively with synthetic data, proved its ability to identify and quantify mineral phases on synthetic and real XRD patterns. Trained NN errors were equal to 0.5% for phase quantification on the synthetic test set, and 6% on the experimental data, in a system containing four phases of contrasting crystal structures (calcite, gibbsite, dolomite and hematite). The proposed method is freely available on GitHub and allows for major advances since it can be applied to any dataset, regardless of the mineral phases present.