Effect Of Fe2O3 Research Articles

Effect of Fe2O3 on CeO2 films in the photocatalytic evaluation towards the degradation of brilliant green and oxytetracycline

This paper presents a photochemical synthesis method for producing pure CeO2 deposits and CeO2 deposits loaded with varying proportions of Fe2O3. The deposits were calcined at 950 °C and characterized structurally, compositionally, and morphologically using XRD, XPS, SEM, FT-IR, and Raman spectroscopy techniques. Cerianite and hematite phases were identified in CeO2/Fe2O3 samples, indicating heterogeneous surface deposits. Photocatalytic testing under UV–Vis illumination for 5 h demonstrated promising results. For the degradation of bright green dye, efficiencies of 78.9 % and 90.1 % were achieved for pure CeO2 and CeO2 samples loaded with 1.0 mol% Fe2O3, respectively. Similarly, for oxytetracycline drug degradation, performance rates of 35.3 % and 67.0 % were observed for CeO2 and CeO2 samples loaded with 1.0 mol% Fe2O3, respectively. Recyclability tests showed a gradual decline in photocatalytic performance over successive cycles due to by-product accumulation contaminating the catalyst.

Influence of Fe2O3 on the absorptivity of in situ synthesized solar high-temperature absorbing and storing integrated mullite-based ceramics

Solar energy absorption and storage of integrated ceramic materials is both the absorption of sunlight and storage of sunlight into thermal energy functional materials. In this paper, the effect of Fe2O3 on the solar absorptivity, thermal storage properties, sintering temperature, and physical properties of mullite-based thermal storage ceramics was investigated. The results show that the absorptivity and thermal storage density of the sample AF4 (Bauxite:50 wt%, Clay:50 wt%, Fe2O3:11 wt%) after sintering at 1420 °C are 87.2% and 1116.5 kJ kg−1, respectively; and the unit volume of the AF4 sample can provide the power grid with 918.01 kW h of electricity, save 112.91 kg of coal, and reduce 361.33 kg of CO2 emission. This study systematically elucidated the mechanism of the enhancement of sample absorption caused by Fe3+ doping-induced changes in substrate color, reduction in material forbidden bandwidth, and lattice anharmonic vibration effect, in addition to comprehensively evaluating the feasibility of the optimal AF4 sample for use in solar energy absorbing and storing integrated ceramic materials.

Effect of Fe2O3 on impedance properties of CuO in 1-x(CuO)- x(Fe2O3) Ceramic Composites

Effect of Fe2O3 on impedance properties of CuO in 1-x(CuO)- x(Fe2O3) Ceramic Composites

The thermal shock resistance of in-situ synthesized mullite absorption and storage integrated ceramics for solar thermal power generation

Solar high-temperature thermal power generation systems require thermal storage materials with excellent thermal shock resistance due to the large temperature difference during operation (in the range of 20–800 °C). In this study, mullite-based absorption and storage integrated ceramics were prepared using low-cost bauxite and kaolin as raw materials and Fe2O3 as additive. The effect of Fe2O3 on the thermal shock resistance of mullite-based ceramics was investigated. The results showed that the absorption and bending strength of sample BK4 (bauxite: 50 wt%, kaolin: 50 wt%, Fe2O3: additional 11 wt%) increased by 2.98% (89.8%) and 8.00% (147.10 MPa), with a storage thermal density of 1185.75 kJ kg−1 after 30 thermal shock cycles. The mechanism for the excellent thermal shock resistance of the ceramics is revealed from the aspect of the changes in phase and microstructure of the samples induced by the changes in the mass transfer rate during the thermal shock process. It was calculated that a unit volume of BK4 (with a raw material cost of about 154.22 USD) could generate 974.95 kW h of electricity (saving 119.92 kg of coal) when used in a solar thermal storage system.

Effect of Fe2O3 on ZrTiO4 support for NH3-SCR catalytic performance

The selective catalytic reduction (SCR) NH3 catalyst is mainly used in industrial production and automobile exhaust cleaning. In this study, a novel α%Fe2O3/ZrTiO4 (α=0, 8, 12, 15) catalyst was prepared by the coprecipitation impregnation method. The results show that the NOx conversion rate of 12%Fe2O3/ZrTiO4 catalyst with the optimal composition is high above 80% at 250−400 °C, close to 100% at 300 °C, and N2 selectivity is high above 90% at 200−450 °C. The redox properties, surface acidity, and Oβ/(Oα + Oβ) ratio of ZrTiO4 catalysts are improved after loading Fe2O3 on the ZrTiO4 surface, which is attributed not only to the porous structure of α%Fe2O3/ZrTiO4 catalyst but also to the synergistic interaction between the active component Fe2O3 and the support ZrTiO4. In addition, in-situ DRIFT reactions show that the NH3-SCR reaction of 12%Fe2O3/ZrTiO4 catalyst follows the Eley-Rideal mechanism. A clear reaction mechanism is conducive to a deeper understanding of the reaction process of NOx conversion during SCR. This work provides a feasible strategy for Fe-based SCR catalysts to replace V-based catalysts in the medium temperature range in the future.

Fe2O3- and MnO2-Doped Waste Glasses for Artificial Gems Products

This work, the effect of Fe2O3 and MnO2-doped waste glasses in formula (100−x)waste glasses: x Fe2O3/MnO2 (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 mol%) were prepared using melt quenching technique and all glass sampled were investigated on physical and optical properties. The results exhibited that the density and refractive index of glass samples increased with Fe2O3/MnO2 content increased. The color of Fe2O3 and MnO2-doped waste glasses displayed yellow and purple, respectively, because of absorbance for Fe2O3 near 440 nm and 1,000 nm which homogeneous distribution of Fe3+ (440 nm: 6A1g(S) → 4T2g(G)) and Fe2+ (1,000 nm: 5T2g(D) → 5Eg(D)) ions in the glass matrices while MnO2 around 486 nm as absorption band is assigned to a single allowed 6A1g(S) → 4T1g(G) transition which arises from the Mn3+ ions (3d4 configuration) in octahedral symmetry. Moreover, the CIE L*a*b* for all glass samples were also investigated. The results indicated that glass production from waste glasses is possible and option for recycling waste glasses to produce artificial gems.

Burning characteristics of ammonium nitrate propellant containing fine ammonium perchlorate – influence of porosity of ammonium perchlorate**

AbstractFine porous ammonium perchlorate (PAP) has small holes in its crust, and the voids in the particles are connected to the outside. The porosity of PAP results in fine bubble contamination in a propellant because the voids in PAP cannot be completely charged with a binder. Fine bubble contamination can improve the burning rate characteristics of an ammonium perchlorate (AP) propellant. The influence of the porosity of PAP on the burning characteristics of an ammonium nitrate (AN)/AP propellant and the effect of Fe2O3 as a catalyst on them were investigated in this study. The void fraction of the propellant increased with increasing mass ratio between AP and all oxidizers (ξ) and ranged from 1.3 % to 3.2 %. The porosity of PAP increased the burning rate of AN/AP propellants. This effect increased with decreasing pressure and was independent of ξ. However, porosity had minimal influence on the burning rate of AN/AP propellants with Fe2O3. The effect of the catalyst on the increase in the burning rate due to the porosity of PAP was influenced by pressure and ξ. The effect on the AN/AP propellant was greatest when ξ was in the 0.5–0.6 range.

Effect of Iron Oxide on Self-Healing and Thermal Characteristics of Asphalt Based on Molecular Dynamics Simulation Perspective

To compare the effects of two powders, iron oxide and mineral, on the healing process of asphalt molecules, Fe2O3-asphalt and SiO2-asphalt were constructed by Material Studio software (MS). The mean square displacement, diffusion coefficient, concentration distribution of the asphalt layer, and the thermal conductivity of the two models were analyzed to evaluate the influence of two powders on the diffusion behavior of asphalt molecules on a microlevel. The results show that the effect of Fe2O3 on the diffusion rate of asphalt molecules is greater than that of SiO2 at high temperature, but the effects are similar at low temperature. The diffusion coefficient of the Fe2O3-asphalt model increases faster than that of the SiO2-asphalt model with increasing temperature. Compared with SiO2, Fe2O3 is more conducive to the model’s reaching a state of uniform concentration, which is manifested as the rapid repair of cracks on a macrolevel. The thermal conductivity of the Fe2O3-asphalt model is higher than that of the SiO2-asphalt model.

Influence of Fe2O3, MgO and Molarity of NaOH Solution on the Mechanical Properties of Fly Ash-Based Geopolymers.

The use of waste from industrial activities is of particular importance for environmental protection. Fly ash has a high potential in the production of construction materials. In the present study, the use of fly ash in the production of geopolymer paste and the effect of Fe2O3, MgO and molarity of NaOH solution on the mechanical strength of geopolymer paste are presented. Samples resulting from the heat treatment of the geopolymer paste were subjected to mechanical tests and SEM, EDS and XRD analyses. Samples were obtained using 6 molar and 8 molar NaOH solution with and without the addition of Fe2O3 and MgO. Samples obtained using a 6 molar NaOH solution where Fe2O3 and MgO were added had higher mechanical strengths compared to the other samples.

Experimental study on Denitrification and in-situ reduction of NO with Fe2O3 catalyst during coke combustion

ABSTRACT Fe2O3, as a cheap and readily available metal catalyst, can effectively reduce the emission of polluting gases in the combustion process, which is an encouraging way to realize the clean utilization of coke. This work focuses on the effect of Fe2O3 in denitration (deNOX) and in-situ reduction of NO during civil clean coke combustion. The influence of catalyst addition and temperature on char-N migration was discussed. Results showed that the catalytic reduction activity is the best when the addition amount is 3%. The reaction is accelerated and the NO emission time is shortened with an increase of combustion temperature, which is mainly due to the enhanced promotion of Fe2O3. Fe reacted with NO, further reducing its releasing amount. Furthermore, char has more significant effects on the reduction of NO in the presence of CO and Fe2O3, up to 90%. Thus, the effect of Fe2O3 on reaction paths is determined. The reduction effect of Fe2O3 on NO was mainly due to the formation of reduced Fe0 during the pyrolysis process. This study can provide some theoretical guidance for the pollution control of loose coal combustion in rural areas.

Effect of Fe2O3 as an Aggregate Replacement on Mechanical, and Gamma/ Neutron Radiation Shielding Properties of Phosphoaluminate Glasses

Effect of Fe2O3 as an Aggregate Replacement on Mechanical, and Gamma/ Neutron Radiation Shielding Properties of Phosphoaluminate Glasses

Effect of Fe2O3 on the Crystallization Behavior of Glass-Ceramics Produced from Secondary Nickel Slag

In this paper, glass-ceramics were prepared from secondary nickel slag by the melting method. The effects of Fe2O3 on the crystallization behavior of glass-ceramics were investigated by differential thermal analysis, X-ray diffraction, and scanning electron microscopy. The properties of glass-ceramics such as Vickers hardness, bending strength, and acid and alkali resistance were systematically discussed. The results indicate that the crystallization temperature (Tc) and transition temperature (Tg) of the glass show a trend of decreasing and then increasing with the increase in Fe2O3 content. The precipitation and refinement of the crystalline phase were promoted significantly when the Fe2O3 content was lower (≤9.32 wt%), while the crystallinity decreased slightly when the Fe2O3 content increased to 12.42 wt%. The promotion of crystal precipitation led to the depolymerization of the glass network. When the Fe2O3 content was 9.32 wt%, the sample exhibited the best crystallization ability, consisting of uniformly distributed anorthite, ferrobustamite and glass phases, while the Vickers hardness and bending strength were 11.42 GPa and 121 MPa, respectively.

Variation of gas composition and energy utilization in biomass CLG process with Fe and Ca oxides through thermodynamic simulation

Chemical looping gasification (CLG) proves to be effective route for biomass thermal conversion for quality gas production. Fe2O3 and CaO were applied in sawdust thermal decomposition as oxygen carrier and CO2 absorption agent to improve syngas composition and yield. The CLG process was investigated based on experiment and process model simulation. Process model was developed based on thermodynamic equilibrium and kinetics of 22 representative reforming reactions in CLG, with the model applicability validated with experimental results. The effect of Fe2O3 and CaO addition on CLG process, including product distribution, gas composition, energy balance and exergy efficiency, was analyzed through extensive simulation under varied combination of reaction temperature(773 ∼ 1273 K), blending ratio of Fe2O3 (0 ∼ 2) and CaO (0 ∼ 2) conditions in order to clarify the effect of variables. Especially the interaction between Fe2O3 and CaO addition on process performance was discussed to discover the potential synergetic effect on mechanism. The blending of Fe2O3 or CaO changed the gas composition with improved oxidation and reforming reactions. Optimum syngas production with maximum H2 and CO yield 682 mL/g was achieved at 1073 K CLG process. And the blending ratio of oxidant was an important factor influencing the energy balance and exergy efficiency, with the equivalent point between CLG reaction heat and char combustion heat appeared at 0.4–0.45 Fe2O3 addition. The results achieved from process simulation would be informative for CLG process mechanism understanding and efficient syngas conversion.

Effect of Fe2O3 on the leaching behavior of Cr in hazardous waste incineration fly ash after thermal treatment

The effect of Fe2O3 on the leaching behavior of Cr in hazardous waste incineration fly ash (HWFA) after thermal treatment was investigated. Addition of Fe2O3 could inhibit the static leaching behavior of Cr at most temperature conditions: the maximum reduction in leaching was 98.3% at 1200 °C. Long-term dynamic leaching behavior of Cr could be inhibited when using a thermal treatment temperature of 1200 °C and proportion of Fe2O3 exceeding 14.3%. At 1200 °C, Fe2O3 reacted strongly with the hazardous fraction of Cr in HWFA to form a stable chromite (Fe+2Cr2O4). The study results illustrate that the leaching behavior of Cr in HWFA after thermal treatment is affected by addition of Fe2O3 and treatment temperature. Adding Fe2O3 could effectively control the static and dynamic leaching behavior of Cr in HWFA after thermal treatment at 1200 °C, but excessive Fe2O3 addition accelerated dynamic leaching rate of Cr in HWFA after thermal treatment at 1100 °C.

Numerical and experimental determination of optical properties and thermal conductivity of ceramic composites based on fumed silica and silica fiber

The thermal insulation material composed of fiber-reinforced fumed silica (in the raw and opacified with silicon carbide, zirconia or titania powders) was produced and analyzed. Optical properties (scattering and absorption coefficients) were experimentally examined in the spectral range of 0.9 – 4.7 µm by the solution of the inverse problem of radiative transfer. The inverse problem was based on the invariant embedding equation and the measured spectral directional-hemispherical reflectance. The effect of silicon carbide opacifier addition on the optical properties, effective and radiative thermal conductivity was estimated. The calculated radiative thermal conductivity of thermal insulations with various volume fractions of SiC opacifier was compared to the one deduced from the effective thermal conductivity using the calorimetric technique of conductive and radiative components separation. The effective thermal conductivity was measured by the quasi-stationary technique in the temperature range of 373 – 1173 K. The results of the inverse problem solution were compared to the calculations based on the Mie theory and the measured size distribution of silicon carbide particles. The experimental scattering coefficient was shown to be smaller than the calculated one. At the same time, absorption coefficients demonstrated mutual consent. Possible uncertainties in SiC powder size and the complex refractive index of the basic material were considered as a probable explanation of the obtained results. The size distribution of SiC opacifier was numerically optimized to obtain as low Rosseland mean radiative thermal conductivity as possible. The influence of the opacifier chemical composition was analyzed by collating radiative thermal conductivity deduced from the measured effective thermal conductivity to ones calculated using Mie theory. Finally, the effect of Fe2O3, Si3N4, TiO2, graphite, ZrO2, TiN, TiC, AlN opacifiers was numerically analyzed using Mie theory. Compounds based on titanium and an iron sesquioxide were shown to be promising opacifiers for high temperature applications.

Investigation on Ash Fusion and Slagging Properties of Coal under Reducing Atmosphere

ABSTRACT Liquid slag tapping at low operation temperature is a major challenge for the application of entrained-flow slagging gasifier. To obtain and elucidate a regulation on stable liquid slag tapping, the SiO2-Al2O3-(CaO+MgO+Na2O+K2O)-Fe2O3 phase diagrams of ash fusion temperatures as well as the ash viscosity and components were studied with ash fusibility apparatus, high-temperature viscometer, SEM-EDS and FactSage software. Meanwhile, the potential slagging properties were analyzed by the difference between soften temperature and deformation temperature (DSI), base/acid ratio (B/A) and slag viscosity index G. Results indicated that the contours of fluid temperature (FT) in the SiO2-Al2O3-(CaO+MgO+Na2O+K2O) pseudo-ternary diagrams presented inverted V-shaped distribution. Attributing to the positive effect of Al2O3 and the downward parabola effect of SiO2, the FT first decreased and then increased with the increased SiO2/Al2O3 at the minimum value of around 3.25. Also, with the increase of (SiO2+ Al2O3+ CaO+MgO+Na2O+K2O)/Fe2O3, the FT showed a V-type distribution with a minimum value at 94:6, yet the effect of Fe2O3 was slight. Besides, high content of CaO+MgO+Na2O+K2O effectively reduced the FT, which favored the formation of molten slag and operation economy; but it shortened the DSI, disadvantaging the formation of long slag and the operation stability. Moreover, decreased ratio of (CaO+MgO)/(Na2O+K2O) not only reduced the FT, but also enlarged the DSI. Finally, a regulation method concerning stable liquid slag tapping at low operation temperature based on ash fusion and slagging properties was proposed: adjusting SiO2/Al2O3 to 3.25 and the mass ratio of Fe2O3 nearby 6.0 wt.%, and doping CaO+MgO+Na2O+K2O with low (CaO+MgO)/(Na2O+K2O) ratio could effectively reduce the FT and viscosity and enlarge the DSI simultaneously, and vice versa.

Effect of Fe2O3 on the pyrolysis of two demineralized coal using in-situ pyrolysis photoionization time-of-flight mass spectrometry

Influence of Fe2O3 on the pyrolysis products distribution of demineralized Hongshaquan (HSQ) and Daliuta (DLT) coal was investigated by a novel in-situ pyrolysis vacuum ultraviolet single photon ionization time-of-flight mass spectrometry. The experiment samples were obtained by mechanical mixing of Fe2O3 and demineralized coal from acid elution with the mass ratio of 10:1, 5:1 and 2:1. Due to the characteristics of in-situ sampling, soft ionization and high vacuum environment, the initial pyrolysis volatiles including alkenes, aromatic hydrocarbons, phenols, bi-phenols and a small amount of sulfur and nitrogen-containing substances can be detected. The results show that Fe2O3 has similar influence on the products distribution of two demineralized coal, and it is relatively stronger on DLT coal than that on HSQ. With the increase of Fe2O3 content, the light fraction content is promoted such as alkenes and aromatic hydrocarbons, but bi-phenols are obviously inhibited. Correspondingly, the heavy products are also decreased, and the evolution peak temperatures of the product increase. Fe2O3 is successively reduced to FeO and Fe while transforming heavy components into light components. The increase of aliphatic carbon (or aromatic hydrocarbon substituted carbon) during coal pyrolysis process is mainly responsible for the decrease pyrolysis peak temperature.

Effects of Fe2O3 on crystallisation and properties of R2O–CaO–MgO–Al2O3–SiO2–Fe2O3 glass ceramics

ABSTRACT The R2O–CaO–MgO–Al2O3–SiO2–Fe2O3 glass ceramics was prepared using granite wastes and Fe2O3. The effect of Fe2O3 on crystallisation and properties of glass ceramics was studied. Results show that the crystalline phases were Fe2TiO5 and K(NaCa)Mg5Si8O22F2 when the content of Fe2O3 was low. The main crystalline phase was Fe1.5Ti0.5O3 when the content of Fe2O3 was high. With the increase of Fe2O3, the crystal size of K(NaCa)Mg5Si8O22F2 reduced and the atomic ratio of Si to Mg increased. The colour of sample varied from greyish green to black with different additions of Fe2O3. The flexural strength with a maxim (101.02 MPa) when the content of Fe2O3 was 4.7 mol-%. Given the low cost of granite wastes and Fe2O3, this new type of black glass ceramics is expected to meet the increasing demand from the market of building decoration due to its excellent properties.

Phase formation, microstructure development, and mechanical properties of kaolin‐based mullite ceramics added with Fe2O3

AbstractThe effects of Fe2O3 on phase evolution, density, microstructural development, and mechanical properties of mullite ceramics from kaolin and alumina were systematically studied. X‐ray diffraction results suggested that the ceramics consisted of mullite, sillimanite, and corundum, in the sintering range of 1450°C–1580°C. However, as the sintering was raised to 1580°C, mullite is the main phase with a content of 94%, and the corundum phase content is 5.9%. Simultaneously, high‐temperature sintering had a positive effect on the densification of the mullite ceramics, where both the bulk density and flexural strength could be optimized by adjusting the content of Fe2O3. It was found that 6 wt% Fe2O3 was optimal for the formation of rod‐shaped mullite after sintering at 1550°C for 3 h. The sample's maximum bulk density was 2.84 g/cm3, with a flexural strength of 112 MPa. Meanwhile, rod‐shaped mullite grains with an aspect ratio of ~9 were formed. As a result, a dense network structure was developed, thus leading to mullite ceramics with excellent mechanical properties. The effect of Fe2O3 on the properties might be attributed to the fact that Al3+ ions in the [AlO6] octahedron were replaced by Fe3+ ions, resulting in lattice distortion.

Gold Solubility in CaO-SiO2-Al2O3-Fe2O3 Slags

Gold solubility in the CaO-SiO2-Al2O3-Fe2O3 slag system was measured at 1723 K under an oxidizing atmosphere. Gold solubility in the present slag system increased with increasing slag basicity, which was quantified by the Vee ratio (= CaO/SiO2), theoretical optical basicity, and activity of CaO. However, the effect of Fe2O3 and Al2O3 on gold solubility was negligible. From the thermodynamic assessment, it was found that gold was stabilized as the AuO− (aurate) complex ion, and thus the dissolution reaction into the slag was proposed. The aurate capacity was originally defined from the dissolution reaction. The iso-Au solubility contours were plotted in the CaO-Fe2O3-(SiO2 + Al2O3) pseudo-ternary diagram, from which the lower content of CaO can be proposed to be useful for higher recovery of gold (i.e., lower solubility) based on the thermodynamic view during pyrometallurgical processing of gold-containing E-waste materials. However, because the viscosity of the slag increases by decreasing the content of CaO, the operating window for best practice should be carefully proposed by considering the physicochemical properties of molten slag.