Fe2O3 Ratio Research Articles

Photothermal Conversion Performance of Fe3O4/ATO Hybrid Nanofluid for Direct Absorption Solar Collector

In order to enhance the efficiency of direct absorption solar collectors, this study carried out an experimental analysis about the optical and photothermal conversion performance of Fe3O4, ATO (Antimony-doped tin oxide), and Fe3O4/ATO nanofluids with a total concentration of 0.1 wt%. According to the results of the experiments, Fe3O4 nanofluid outperforms ATO nanofluid in terms of optical absorption; nevertheless, at wavelengths shorter than 600 nm, it also shows significant scattering reflection. The solar-weighted absorption coefficient of Fe3O4/ATO nanofluid rose from 0.863 (mFe3O4/mTotal = 0.2) to 0.932 (mFe3O4/mTotal = 0.8) when the optical path length increased from 0.01 m to 0.06 m. Moreover, the Fe3O4/ATO hybrid nanofluid achieved a photothermal conversion efficiency of 0.932 when the mass ratio of Fe3O4 to total mass was 0.2, surpassing the efficiencies of 0.892 and 0.898 recorded for 0.1 wt% ATO and Fe3O4 nanofluids, respectively. When present together, the opposing optical characteristics of Fe3O4 and ATO boost photothermal conversion performance, which is anticipated to raise the efficiency of direct absorption solar collectors.

Geochemistry of shales of middle Permian Barren Measures Formation, West Bokaro Basin, India: implications on provenance, paleodepositional and paleoclimatic conditions

Geochemical analyses of fine-grained clastic sedimentary rocks, such as shales, are significant since they portray the nature of the control factors from source to sink in a sedimentary basin, and help characterizing the heterogeneity in potential source and/or reservoir rocks. Bulk rock geochemistry (including major element oxides, trace elements and rare earth elements) of 20 shale samples from the Permian Barren Measures Formation, West Bokaro Basin, Peninsular India, is presented to decipher the provenance, paleo-weathering, paleotectonic, paleo-depositional and paleoredox conditions of the basin within the Lower Gondwana paleogeographic framework. X-ray diffraction (XRD) peaks and scanning electron microscopy (SEM) reveals an abundance of quartz, muscovite and clay minerals, viz., illite, kaolinite, etc., with less abundant feldspar and glauconite. The concentrations of the major element oxides, the trace elements and rare earth elements (REEs) of the shale samples are compared with predefined standards such as PAAS and UCC. The CIA (chemical index of alteration) and the A–CN–K values, based on the ratios of the major element oxides, signify intense chemical weathering. The ratios of Sr/Cu versus Rb/Sr and K2O/Al2O3 versus Ga/Rb, and high ΣREE values indicate a temperate paleoclimate. Ratios of the major element oxides (e.g., K2O/Na2O versus SiO2) suggest a passive tectonic setting. The Eu/Eu∗ and (Gd/Yb)n values depict predominantly post-Archean granitic and gneissic source rocks. The ratios of trace elements, viz., Th/Sc, Th/Co, Th/Cr, La/Sc and Eu/Eu∗, and the distribution pattern of the REEs (higher LREE in comparison to HREE) attest to a felsic-intermediate source from a nearby provenance. The redox sensitive trace elements, such as V and Ni, indicate a dysoxic condition that prevailed during deposition. The ratios of Fe2O3 versus MgO and Log (MgO/Al2O3) versus Log (K2O/Al2O3), and the ternary plots of Fe2O3–MgO–SiO2/Al2O3 suggest a non-marine to deltaic transitional environment. Such evidence of marine influences during the sedimentation of the Permian Barren Measures Formation confirms the fluvio-marine transgressive paleogeography inferred from sedimentological and paleontological inputs from the Gondwana Basins in Peninsular India, and opens up a scope for regional correlations of paleogeographic changes during the Middle Permian (Guadalupian) across the Gondwanaland.

Insight into the adsorption mechanism of arsenic and selenium by different mineral adsorbents

The adsorption characteristics of arsenic and selenium by CaO, CaCO3, MgO and Fe2O3 at different temperatures and the influence of steam are investigated using simulated flue gas by a vertical furnace. Experiments show that the adsorption capacity of CaCO3 for arsenic and selenium reached the maximum at 900 °C. Steam addition exerts a notable inhibitory impact on the adsorptive efficacy of CaO, MgO, and Fe2O3. Low-concentration steam has a certain improvement on adsorption of arsenic by CaCO3, while excessive steam will have an inhibitory effect. Based on CaCO3, the adsorption effect of composite minerals is investigated. When the mass ratio of CaCO3 and Fe2O3 is 3:1, the best adsorption is achieved, attributing to the generated Ca2Fe2O5 at high temperature. It is verified in the drop tube furnace. The relative enrichment factor of As and Se are 88.24 % and 75.11 %, respectively, which achieved efficient removal.

The effects of raw materials particle sizes on the solid-state reaction progress, morphology and magnetic properties of M-type strontium hexaferrites

In this work, the effects of SrCO3 and Fe2O3 particle size on the reaction process, morphology and magnetic properties of M-type strontium hexaferrites (SrM) have been further studied. Pure strontium hexaferrite magnetic sample based on SrCO3 and Fe2O3 molar ratio of 1:6 has been successfully prepared at 1150 °C. The results indicated that Fe2O3 particle size was the main factor of affecting the formation of SrM, a pure SrM phase magnetic sample was able to obtain at lower calcination temperatures by using fine Fe2O3 powder as raw material, and at the same calcination temperature, a sample using fine Fe2O3 powder as raw material was able to obtain pure SrM phase magnetic sample with shorter holding time. When the mean particle size of Fe2O3 was below 60 nm, a pure SrM phase magnetic sample was able to form at 1150 °C at a molar ratio of 1:6 of SrCO3 and Fe2O3. In this case, the magnetic parameters of the sample with the optimum magnetic parameters were saturation magnetization MS = 77.8 emu/g and coercive force HC = 4122 Oe. And the solid-state reaction process of the corresponding samples was slightly faster when the mean particle size ratio of Fe2O3 and SrCO3 was between 0.35 and 0.36. Assuming that a SrCO3 particle is surrounded by Fe2O3 particles, it can be inferred that the corresponding molar ratio of Fe and Sr of the nearest raw material particles is between 3.6 and 3.8.

Engineered hybrid iron‐cobalt metal oxide nanoparticles for effective adsorption of malachite green dye

AbstractBACKGROUNDHybrid iron and cobalt metal oxide nanoparticles are well known; however, are not optimized in terms of size and stability. We engineered these hybrid nanoparticles using the co‐precipitation method and characterized them by various techniques, which are then used for the effective adsorption and removal of malachite green (MG) dye.RESULTSThe ideal conditions for synthesis are determined to be 50:50 ratio of Fe2O3 and CoO, pH of 11, temperature range of 40 °C–60 °C, and reactant addition time of 20 min. These hybrid nanoadsorbents effectively eliminated MG dye from aqueous solutions. Factors such as initial MG dye concentration, pH of the medium, contact time, temperature, and nanoadsorbent dose were optimized for the MG removal to achieve a maximum removal efficiency of 96.9%. Non‐linear fitting of data indicates that both Langmuir and Freundlich models provided the best fit, suggesting the presence of both monolayer and multilayer adsorption of MG on hybrid nanoparticles. The kinetics of MG dye removal are better controlled by the intraparticle diffusion (IPD) phenomenon. The adsorption of MG onto the hybrid nanoparticles was confirmed to be endothermic, with negative ΔG and positive ΔH values. The optimized synthetic conditions also positively impacted the hybrid nanoparticles which enhanced the adsorption and exhibited ferromagnetic behavior as compared to the superparamagnetic behavior reported in the literature, making them significantly important for dye removal applications.CONCLUSIONThese findings demonstrate the potential of optimized hybrid nanoparticles as effective nanoadsorbents for dye removal applications, with implications for further applications in photocatalysis and sensing. © 2024 Society of Chemical Industry (SCI).

Preparation of Fe2O3/g-C3N4 Photocatalysts and the Degradation Mechanism of NOR in Water under Visible Light Irradiation

Fe2O3/g-C3N4 nano-heterostructures for photocatalytic degradation of NOR (norfloxacin) were successfully prepared by combining co-precipitation and calcination methods. The g-C3N4, Fe2O3, and different composite ratios of Fe2O3/g-C3N4 (FeCNs) were characterized by XRD, SEM, XPS, UV-vis DRS, PL, and electrochemical tests, and the mechanism of photocatalytic degradation of NOR was analyzed. The results indicated that the semiconductor was attached to the surface of g-C3N4 in the form of α-Fe2O3 crystal with good crystalline structure. The composite of Fe2O3 with g-C3N4 increased the specific surface area of the material, effectively reduced the band gap, strengthened the photogenerated e−/h+ pair separation, and improved the photocatalytic performance of the composite. The photocatalytic degradation of NOR was consistent with the quasi-primary reaction kinetic model. Among them, FeCN-25wt% showed the optimal photocatalytic degradation of NOR (72.3%) with the largest degradation rate (k = 0.00900 min−1). The Fe2O3/g-C3N4 composite structure is inferred to be a Z-type heterojunction.

Kyanite and Cordierite‐Andalusite occurrences in parts of Barrow's Staurolite zones – The effects of high ferric iron

AbstractGeorge Barrow's maps (1893, 1912) of the metamorphic zones named after him in the south‐eastern Scottish Highlands, show a prominent staurolite zone running from the west of Glen Clova to the North Sea coast near Stonehaven in the east. Pelitic mica schists throughout this zone commonly show principal mineral assemblages of staurolite+biotite+garnet+muscovite +quartz (St + Bt + Grt), with sodic plagioclase, ilmenite and sometimes magnetite as common accessories; these schists have bulk compositions corresponding with those of common Dalradian metasediments. However, the mineral assemblages on the low‐ and high‐grade margins of the staurolite zone show evidence of changes from west to east. Lower grade assemblages near Stonehaven include chloritoid+biotite, which has not been found further west in the classic ‘Barrovian’ sequence; whilst the higher grade assemblages near Stonehaven lack kyanite, which is widely seen further west. The Stonehaven area has been suggested to have under gone metamorphism at lower pressure (P) than the classic region of the ‘Glens’ inland to the west.This paper describes the occurrence at middle grade in the broad staurolite zone, of unusual bulk rock compositions showing high ratios of Fe2O3/(Fe2O3 + FeO) and MgO/(MgO + FeO) (abbreviated to M/FM). The high M/FM assemblages are distinct from those of the common St‐Bt‐Grt schists. The high ratios of ferric to ferrous iron are thought to result from original sedimentary protolith compositions, that led to metamorphism at relatively high conditions of oxygen fugacity (ƒo2), and resulted in the formation of haematite‐bearing assemblages, rather than ones carrying accessory ilmenite and magnetite as in the common St + Bt + Grt rocks.In the west (Glen Lethnot), the haematite‐bearing pelites show the occurrence of kyanite at a distinctly lower grade than the common (haematite‐free) pelites, and a transition from staurolite‐biotite (St + Bt) through staurolite–kyanite‐biotite (St + Ky + Bt) to kyanite‐biotite (Ky‐Bt) assemblages occurs with increasing abundance of haematite and higher bulk M/FM values. In all bulk compositions, the upgrade formation of kyanite may be associated with the movement of the St + Ky + Bt assemblage to lower M/FM bulk compositions with increasing temperature (T). The difference in the temperature of lowest‐grade kyanite formation in haematite‐rich schists, compared with that in common haematite‐free schists may approach 50°C.In the east (Stonehaven section), the haematite‐bearing assemblages are much rarer than in Glen Lethnot, but those found so far are very distinctive in showing large porphyroblasts of probable cordierite (typically altered to chlorite and sericite). Occasional assemblages of andalusite‐cordierite‐biotite (And‐Crd‐Bt) also occur in the haematite‐bearing rocks and confirm lower pressures of metamorphism near Stonehaven than those seen further west in Glens Clova, Lethnot and Esk.

Cocos nucifera mediated green synthesis and characterization of BiOCl-Fe2O3 nanocomposite for photocatalytic dye degradation and electrochemical sensing of dopamine

In this study, BiOCl-Fe2O3 nanocomposite was synthesized by mixing 1:1 ratio of pre-prepared BiOCl and Fe2O3 in 100 mL of H2O using Cocos nucifera (coconut milk) as a green fuel through the microwave irradiation method. X-ray diffraction analysis (XRD), Scanning electron microscopy (SEM) with, Fourier transform infrared spectroscopy (FTIR), UV–vis spectroscopy(UV–vis), and photoluminescence (PL) spectroscopy analysis were used to determine the structure, morphology, and optical features of synthesised nanocomposites. The characterized composites were used to dye degradation and electrochemical activity. Synthesized BiOCl-Fe2O3were degraded methylene blue (MB) 96.2 % in 105 min irradiation of visible light. The BiOCl-Fe2O3exhibits significant catalytic activity towards dopamine(DA) under optimal conditions. Cyclic Voltammetry(CV) and Linear sweep voltammetry (LSV) with different concentrations of DA was studied. These results indicate that this BiOCl-Fe2O3 is an effective approach for the precise and reliable identification of DA signals in biological samples.

EMI-shielding response of GO/Fe3O4/polypyrrole(PPy)/thermoplastic polyurethane (TPU) composites

In the present study, thermoplastic polyurethane was reinforced with GO/Fe3O4/PPy nanocomposites with varying GO:Fe3O4 ratio to develop high-performance electromagnetic interference (EMI) shields. GO/Fe3O4/PPy fillers were prepared by adding polypyrrole (PPy) nanotubes, synthesized by the soft-template method from oxidative polymerization of pyrrole, to graphene oxide decorated with Fe3O4 nanoparticles prepared by a sonochemical method. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy were performed to reveal the structural and morphological properties of GO/Fe3O4/PPy nanofillers, and the structure and thermal properties of the GO/Fe3O4/PPy/TPU nanocomposites was studied by cryofracture SEM and thermogravimetry (TGA). The effect of GO:Fe3O4 ratio on the electrical conductivity, magnetic permeability, permittivity, and electromagnetic-wave-shielding performance of GO/Fe3O4/PPy/TPU nanocomposites was investigated in the X-band frequency range. The maximum EMI efficiency was 4.81 dB with increasing GO:Fe3O4 ratio in GO/Fe3O4/PPy/TPU composites, with blocking of 66.72 % of the incident electromagnetic wave.

Investigation of bionano additives in red algae Cyanidioschyzon merolae ultrasonified MgO/MWCNT catalyzed biodiesel in optimized engine performance

Renewable energy research is burgeoning with the anticipation of finding neat liquid fuel. Ultra sonification assisted biodiesel was derived from red algae Cyanidioschyzon merolae, with biodiesel yield of 98.9%. The results of GC MS of the prepared biodiesel showed higher concentration of methyl palmitate, methyl oleate, and stearate. This composition is appreciable, as this plays significance in desirable pour & cloud point properties. NMR spectrum revealed the ester linkages, presence of olefins, and α methyl position in olefins. Mixture of 30 wt% of biodiesel in diesel exhibited work efficiency, and also exhibited low pour point and, lower viscosity values. CeO2 and Fe2O3 nano particles were bio reduced, and were added as nano additive in biodiesel. 1:1 ratio of CeO2 and Fe2O3 added to biodiesel maximised the combustion ability of fuel owing to the oxygen storage capacity of CeO2. Further, this combination produced a satisfactory calorific value. Imbalanced ratios disrupted the catalytic and oxygen storage effects, reduced the overall energy release and calorific value of the biodiesel blend. Pour point and cetane number value of biodiesel blend ultrasonifacted with 1:1 mass ratio of Fe2O3 and CeO2 was observed to be around −7 °C and 53 °C respectively, and was better than other compositions. 1:1 mass ratio of NPS blended with 30 wt% BD in diesel showed tremendous increase in brake thermal efficiency, torque, and power. HC, NOX, and SOX emissions were reduced by 42.8%, 19.3%, and 57% respectively with 1:1 Fe2O3 and CeO2 mixed biodiesel blend. CeO2 favourably improved the oxygen storage capacity of the fuel, whereas Fe2O3 showed decrease in formation of gums and sediments in biodiesel.

Generation and persistency of combustion-derived environmentally persistent free radicals from phenolic compounds over a Fe2O3/SiO2 surface

Combustion of organic solid wastes releases phenolic compounds which can act as precursors in the formation of environmentally persistent free radicals (EPFRs) in the post-flame, cooling zone of waste combustion. The study investigated the generation mechanism of EPFRs from phenolic compounds catalyzed by transition metals in air atmosphere under simulated combustion conditions. Representative combustion-derived phenolic compounds were used, and SiO2 particulates containing different mass ratio of Fe2O3 were synthesized as carriers. EPFRs formed had g-factors between 1.9998 and 2.0066, indicating phenoxyl-, cyclopentadienyl-, and semiquinone-type radicals, along with paramagnetic F-centers. The promotion effect of phenolic compounds on EPFR formation during heating decreased as catechol > hydroquinone > phenol > p-cresol. This trend is related to hydroxyl groups and activation energy. In particular, catechol chemically adsorbed on Fe2O3 at 600 K led to the formation of EPFRs with relatively high spin concentrations (up to 1.28 × 1017 spin/g). Higher Fe2O3 concentrations promoted the transformation of phenoxyl-type radicals into cyclopentadienyl-type and paramagnetic F-centers. However, as the Fe2O3 loading increased from 1.25% to 5%, the density of EPFRs decreased. The findings related to the influence of various precursors and Fe2O3 concentration on EPFR formation provide valuable insights for estimating EPFR generation and associated risk during combustion processes.

A study on the performance of a recyclable adsorbent La@Fe for phosphate adsorption in wastewater

Phosphorus(P) is the key element of the growth of phytoplankton, and is also significant cause of water eutrophication. In this work, the magnetic Fe3O4 (FE) microspheres were employed as the core material, the La compound was coated on the surface of the FE microspheres and the adsorbent obtained was denoted as La@Fe. The effects of preparation conditions including the dosage of NaOH, the preparation time, the ratio of FE and LaCl3 (LC), and the stirring time were discussed. The optimized La@Fe has a good adsorption capacity (130–160 mg·g−1) and strong magnetic recovery capacity (43.4 emu/g). In the low concentration (1 mg·L−1), the optimized La@Fe still had an excellent performance. It can keep a good adsorption in a wide pH range (3−8). Except Na2CO3, common anions (NaHCO3, NaCl, NaNO3, Na2SO4, KF, KNO2) in the wastewater could not affect the adsorption capacity of La@Fe. After 7 regeneration, the adsorption capacity of La@Fe reduced by 25% indicating the excellent regeneration property of La@Fe. The La@Fe was analyzed by SEM, TEM, XRD, XPS, BET, and LPS, and the obtained results showed that the particles of La@Fe were spherical, the particle sizes were between 0.1 and 100μm. The main components at the surface of La@Fe was La-(OH), which adsorbed phosphate to form La-PO4. The specific surface area of La@Fe was small and the mesopores were main pore structure. In addition, the adsorption kinetics analysis indicated that the Elovich model worked well on modeling La@Fe adsorbing phosphate, so the adsorption was chemical adsorption with heterogeneous adsorbing surfaces. Adsorption isotherms experiments revealed that the increasing adsorption temperature would enhance the adsorption capacity of La@Fe. It could be obtained from the thermodynamic experiments that the adsorption process was endothermic and chemical adsorption. Therefore, La@Fe is an excellent phosphate adsorbent and has a good application prospect in the field of phosphorus recovery and adsorbent reuse.

Degradation of TCH by Fe3O4/B4C catalyzed heterogeneous Fenton oxidation

In this work, Fe3O4/B4C (FeB) composites were successfully prepared by a facile co-precipitation process. FeB composites were characterized using XRD, FTIR, N2 adsorption-desorption, XPS, etc techniques and then used as heterogeneous Fenton catalysts to activate green oxidant (H2O2) for the degradation of TCH. The removal efficiency of TCH by FeB composites was explored including different parameters of Fe3O4 loading on B4C, catalyst dosage, initial solution pH, H2O2 dosage, and reaction temperature. The highest photo-Fenton catalytic efficiency was obtained for the composites with a mass ratio of Fe3O4 to B4C of 1:0.75. At this time, the removal efficiency of Fe3O4/B4C was 2 times and 391 times that of the parent Fe3O4 and B4C, respectively, and B4C can effectively improve the efficiency of the Fenton cycle. h+, e-, and ·OH were mainly responsible for the degradation of TCH by Fe1B0.75 composites. After repeated use for five times, the removal efficiency of the catalyst was reduced by only 8.0%. The disparity in work functions by density functional theory calculations confirmed the formation of an internal electric field at the Fe3O4/B4C composites interface, which contributed the transfer of charge carriers between the Fe3O4 and B4C. Moreover, the FeB composite showed a high stability, indicating that FeB composites may be a promising heterogeneous catalyst.

Revealing the mechanism of Ce promoter in modulating product distribution of CO2 hydrogenation over Fe-based catalysts

This study elucidates the influence of the Ce promoter on the structure and surface intermediates of Fe-based catalysts and provides insights into the mechanism controlling the distribution of CO2 hydrogenation products. The product distribution revealed a volcano-shaped trend for the selectivity of light olefins and C5+ products as the Ce content increased from 0 to 10 wt%, whereas the selectivity for CH4 shows an inverted volcano-shaped trend. Concurrently, the selectivity for CO gradually increased from 14.4 % to 58.8 %. When the Ce content was 1 wt%, the selectivity for light olefins and C5+ products reached maximum values of 41.4 % and 19.1 %, respectively, and the selectivity for methane decreased to 34.3 %. Characterization by in situ X-ray diffraction (XRD), in situ infrared spectroscopy (IR), and X-ray photoelectron spectroscopy (XPS) techniques demonstrated that the variation in product distribution could be attributed to the altered ratio of Fe3O4 to Fe5C2 species, surface enrichment of the Na promoter, and generation and desorption of surface intermediate species induced by the Ce promoter. These factors affect the rate of the reverse water gas shift reaction (RWGS) and the subsequent Fischer-Tropsch (FT) reaction, thereby modulating the product distribution. Understanding the regulation mechanism of the CO2 hydrogenation product distribution by the Ce promoter is expected to provide valuable insights for guiding the design of catalyst structures.

The Optimal Doping Ratio of Fe2O3 for Enhancing the Electrochemical Stability of Zeolitic Imidazolate Framework-8 for Energy Storage Devices

This paper aims to discover a novel composite material that has great potential for manufacturing high-performance supercapacitors suitable for diverse applications, such as electric vehicles, portable electronics, and stationary energy storage systems. Zeolitic imidazolate framework-8 (ZIF-8) doped by different concentrations up to 5 wt.% of nanosized Fe2O3 have been prepared (ZIF-8/Fe2O3). The effect of doping ratio 1, 3, and 5 wt.% on the structural and electrochemical properties of ZIF-8/Fe2O3 has been investigated. The structural characterization has been carried out using TGA, BET, XRD, and FTIR. The XRD analysis revealed that the crystalline size of our sample increased by approximately 16% as a result of doping ZIF-8 with 5 wt.% of Fe2O3. The structural analysis of the doped samples revealed that the material exhibited enhanced thermal stability and porosity, with an increase of approximately 105 m2/g. The introduction of doped nanometal oxides improved the capacitance value of ZIF-8 by significantly increasing its surface area. Additionally, the electron transport efficiency within ZIF-8/5 wt.% Fe2O3/electrode is increased. The Nyquist plot decreases as the doping of Fe2O3 increases. This indicates a decrease in the charge transfer resistance at the electrode–electrolyte interface, which is desired in applications such as batteries, fuel cells, or electrochemical sensors where faster electron transfer is needed for improved performance.

Enhanced degradation of carbamazepine in water over Fe3O4@ZIF-8 nanocomposites with persulfate or peroxymonosulfate as activator

In this work, the Fe3O4@ZIF-8 catalyst was prepared by combining Fe3O4 with ZIF-8 for degrading carbamazepine (CBZ) in water, using activated persulfate (PS) and peroxymonosulfate (PMS). We investigated the optimal catalysts and reaction conditions for using PS or PMS as activators by varying the pH, temperature, catalyst dosage, as well as the dosage of PS and PMS, respectively. The results demonstrated that the CBZ removal rate using Fe3O4@ZIF-8 reached 98.1% after 30 min with a mass ratio of Fe3O4 to ZIF-8 = 3:1, temperature = 40°C, catalyst dosage = 0.50 g·L−1, and PS dosage = 0.25 g·L−1, using pH = 3.0. Characterization results show due to the fact that the presence of ZIF-8 facilitates the dispersion of the catalytic active species Fe3O4, prevents the agglomeration of the active species, increases the number of active species, and improves the catalytic performance. Furthermore, radical quenching assay and electron paramagnetic resonance spectra successfully identified the main oxidizing components generated in the system, namely SO4•− and •OH.

The Constructing of the Oxide Phase Diagram for Fluoride Adsorption on La-Fe-Al: A Collaborative Study of Density Functional Calculation and Experimentation.

In recent years, fluoride pollution in water is a problem that has attracted much attention from researchers. The removal of fluoride-containing wastewater by adsorption with metal oxide as an adsorbent is the most common treatment method. Based on this, the effect of the doping ratio of La2O3, Fe2O3, and Al2O3 on the fluoride-removal performance was discussed by constructing a phase diagram. In this study, the adsorption mechanism of nanocrystalline lanthanum oxide terpolymer was investigated by density functional theory calculation and experiment. The optimal pH condition selected in the experiment was three, and the adsorption kinetics of fluoride ions were more consistent with the quasi-second-order kinetic model. The adsorption thermodynamics was more consistent with the Langmuir model. When the La-Fe-Al ternary composite oxides achieved the optimal adsorption efficiency for fluoride ions, the mass synthesis ratio was Al2O3:(Fe2O3:La2O3 = 1:2) = 1:100, resulting in a fluoride ion removal rate of up to 99.78%. Density functional calculations revealed that the La-Fe-Al ternary composite oxides had three important adsorption sites for La, Fe, and Al. Among them, the adsorption capacity for HF was Fe2O3 > La2O3 > Al2O3, and for F- was La2O3 > Al2O3 > Fe2O3. This provided good guidance for designing adsorbents to remove fluoride.

The XMM-Newton Line Emission Analysis Program (X-LEAP). II. The Multiscale Temperature Structures in the Milky Way Hot Gas

This paper presents the multiscale temperature structures in the Milky Way (MW) hot gas, as part of the XMM-Newton Line Emission Analysis Program, surveying the O vii, O viii, and Fe-L band emission features in the XMM-Newton archive. In particular, we define two temperature tracers, I OVIII/I OVII (O87) and I FeL/(I OVII + I OVIII) (FeO). These two ratios cannot be explained simultaneously using single-temperature collisional ionization models, which indicates the need for multitemperature structures in hot gas. In addition, we show three large-scale features in the hot gas: the eROSITA bubbles around the Galactic center (GC), the disk, and the halo. In the eROSITA bubbles, the observed line ratios can be explained by a log-normal temperature distribution with a median of logT/K≈6.4 and a scatter of σ T ≈ 0.2 dex. Beyond the bubbles, the line ratio dependence on the Galactic latitude suggests higher temperatures around the midplane of the MW disk. The scale height of the temperature variation is estimated to be ≈2 kpc assuming an average distance of 5 kpc for the hot gas. The halo component is characterized by the dependence on the distance to the GC, showing a temperature decline from logT/K≈6.3 to 5.8. Furthermore, we extract the autocorrelation and cross-correlation functions to investigate the small-scale structures. O87 and FeO ratios show a consistent autocorrelation scale of ≈5° (i.e., ≈400 pc at 5 kpc), which is consistent with the expected physical sizes of X-ray bubbles associated with star-forming regions or supernova remnants. Finally, we examine the cross-correlation between the hot and UV-detected warm gas and show an intriguing anticorrelation.

Effect of impurity components in titanium gypsum on the setting time and mechanical properties of gypsum-slag cementitious materials

Abstract The use of titanium gypsum instead of gypsum as a raw material for the preparation of gypsum-slag cementitious materials (GSCM) can reduce the cost and improve the utilization of solid waste. However, titanium gypsum contains impurities such as Fe2O3, MgO, and TiO2, which make its effect on the performance of GSCM uncertain. To investigate this issue, GSCM doped with different ratios of Fe2O3, MgO, and TiO2 were prepared in this study, the setting time and the strength of GSCM at 3, 7, and 28 days were tested. The effects of different oxides on the performance of GSCM were also investigated by scanning electron microscopy, energy spectrum analysis, X-ray diffraction analysis, and thermogravimetric analysis. The experimental results showed that Fe2O3, MgO, and TiO2 all had a certain procoagulant effect on GSCM and a slight effect on the strength. Through micro-analysis, it was found that the main hydration products of GSCM were AFt phase and calcium–alumina–silicate–hydrate (C–(A)–S–H) gels. Fe-rich C–(A)–S–H gels were observed with the addition of Fe2O3, and Mg(OH)2 and M–S–H gels were observed with the addition of MgO. The addition of TiO2 did not result in new hydration products from GSCM.

Magnetically Chitosan-Silica-Based Biosorbent as Efficient Removal of Au(III) in Artificial Wastewater

The synthesis of chitosan-modified silica-coated iron oxide magnetic material (Fe3O4/SiO2/Chitosan) via the sol-gel process addresses the need for enhanced stability and functionality in various applications. Coating iron oxide magnetic material with chitosan-modified silica is a common strategy to improve biocompatibility and performance. This study investigates the synthesis of Fe3O4/SiO2/Chitosan using sodium silicate as the silica precursor. The synthesis involved sonication of Fe3O4 and sodium silicate for 5 min, followed by adding chitosan in 4% acetic acid with continuous stirring. The mass ratio of Fe3O4:SiO2 was fixed at 0.5:0.73, with varying chitosan masses (0.025, 0.050, and 0.075 g). Characterization techniques used included Fourier-Transform Infrared Spectroscopy (FTIR), X-ray powder Diffraction (XRD), Thermogravimetric analysis, and Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX). The product with the highest mass yield was further analyzed. The variation in the amount of chitosan in the conducted research aimed to determine the optimum chitosan mass that could still bind to the silica framework. Magnetite was confirmed as the primary composition, with the addition of chitosan and silica functional groups observed through vibration absorption characteristics. SEM imaging revealed larger particles after coating. Thermogravimetric analysis showed differences in decomposition patterns between samples. The optimal chitosan content for characterization was determined at 0.050 g. Future applications might include enhanced adsorption processes owing to the optimized structure and composition of Fe3O4/SiO2/Chitosan nanoparticles.