The effectiveness of Elodea nuttallii combined with a mixture of hydrous ferric oxide,zeolite and calcite(HZC)to reduce the internal loading of phosphorus(P)from sediment and its mechanism were studied,and the effect ...The effectiveness of Elodea nuttallii combined with a mixture of hydrous ferric oxide,zeolite and calcite(HZC)to reduce the internal loading of phosphorus(P)from sediment and its mechanism were studied,and the effect of Elodea nuttallii combined with HZC on the composition and function of the microbial communities in the surface sediment was also investigated.The results showed that the combination utilization of Elodea nuttallii and HZC can decrease the risk of phosphorus liberation from sediment to the overlying water,and the controlling efficiency of Elodea nuttallii combined with HZCwas higher than that of Elodea nuttallii or HZC alone.The passivation of labile P measured by diffusive gradient in thin film device and mobile P played a crucial role in the control of internal P loading from sediment by the combined Elodea nuttallii+HZC treatment.HZC capping had a promoting effect on the growth of Elodea nuttallii.This was beneficial to the absorption of phosphorus from sediment by Elodea nuttallii.The combined application of Elodea nuttallii and HZC not only had a certain negative effect on the diversity of bacteria in the surface sediment,but also changed themicrobial compositions of the surface sediment at the levels of phylum and genus.However,the microbial communities in the surface sediment still can perform good ecological function.The above results suggest that the combined application of Elodea nuttallii and HZC has a high potential in the management of internal P loading from sediment.展开更多
Digesting aluminum-bearing minerals and converting ferric oxide to magnetite simultaneously in Bayer digestion process is crucially important to deal with high-iron diasporic bauxite economically for alumina productio...Digesting aluminum-bearing minerals and converting ferric oxide to magnetite simultaneously in Bayer digestion process is crucially important to deal with high-iron diasporic bauxite economically for alumina production.The reaction behaviors of hydrothermal reduction of ferric oxide in alkali solution were studied by both thermodynamic calculation and experimental investigation.The thermodynamic calculation indicates that Fe3O4 can be formed by the conversion of Fe2O3 at proper redox potentials in alkaline solution.The experimental results show that the formation ratio of Fe3O4 either through the reaction of Fe and Fe2O3 or through the reaction of Fe and H2O in alkaline aqueous solution increases remarkably with raising the temperature and alkali concentration,suggesting that Fe（OH）3- and Fe（OH）4- form by dissolving Fe and Fe2O3,respectively,in alkaline aqueous solution and further react to form Fe3O4.Moreover,aluminate ions have little influence on the hydrothermal reduction of Fe2O3 in alkaline aqueous solution,and converting iron minerals to magnetite can be realized in the Bayer digestion process of diasporic bauxite.展开更多
Pure compounds and kaolin were employed to investigate the reaction behavior of ferric oxide in thetrinarysystem Fe2O3?SiO2?Al2O3 during reductive sintering process. The thermodynamic analyses and reductive sintering ...Pure compounds and kaolin were employed to investigate the reaction behavior of ferric oxide in thetrinarysystem Fe2O3?SiO2?Al2O3 during reductive sintering process. The thermodynamic analyses and reductive sintering experimental results show that ferrous oxide generated from the reduction of ferric oxide by carbon can react with silicon dioxide and aluminum oxide to form ferrous silicate and hercynite at 1173 K, respectively. In the trinary system Fe2O3?SiO2?Al2O3, ferrous oxide obtained from ferric oxide reduction preferentially reacts with aluminum oxide to form hercynite, and the reaction of ferrous oxide with silicon dioxide occurs only when there is surplus ferrous oxide after the exhaustion of aluminum oxide. When sintering temperature rises to 1473 K, hercynite further reacts with silicon dioxide to form mullite and ferrous oxide. Results presented in this work may throw a new light upon the separation of alumina and silica present in Al/Fe-bearing materials with low mass ratio of alumina to silica in alumina production.展开更多
We fabricated and characterized two hybrid adsorbents originated from hydrated ferric oxides （HFOs） using a polymeric anion exchanger D201 and calcite as host. The resultant adsorbents （denoted as HFO-201 and IOCCS...We fabricated and characterized two hybrid adsorbents originated from hydrated ferric oxides （HFOs） using a polymeric anion exchanger D201 and calcite as host. The resultant adsorbents （denoted as HFO-201 and IOCCS） were employed for Sb（V） removal from water. Increasing solution pH from 3 to 9 apparently weakened Sb（V） removal by both composites, while increasing temperature from 293 to 313 K only improved Sb（V） uptake by IOCCS. HFO-201 exhibited much higher capacity for Sb（V） than for IOCCS in the absence of other anions in solution. Increasing ionic strength from 0.01 to 0.1 mol/L NaNO3 would result in a significant drop of the capacity of HFO-201 in the studied pH ranges; however, negligible effect was observed for 1OCCS under similar conditions. Similarly, the competing chloride and sulfate pose more negative effect on Sb（V） adsorption by HFO-201 than by IOCCS, and the presence of silicate greatly decreased their adsorption simultaneously, while calcium ions were found to promote the adsorption of both adsorbents. XPS analysis further demonstrated that preferable Sb（V） adsorption by both hybrids was attributed to the inner sphere complexation of Sb（V） and HFO, and Ca（II） induced adsorption enhancement possibly resulted from the formation of HFO-Ca-Sb complexes. Column adsorption runs proved that Sb（V） in the synthetic water could be effectively removed from 30 μg/L to below 5μg/L （the drinking water standard regulated by China）, and the effective treatable volume of IOCCS was around 6 times as that of HFO-201, implying that HFO coatings onto calcite might be a more effective approach than immobilization inside D201.展开更多
Efficient destruction of cyanide by thermal decomposition with ferric oxide addition was proposed. The mechanism of destruction of sodium cyanide with or without ferric oxide addition under various conditions was exam...Efficient destruction of cyanide by thermal decomposition with ferric oxide addition was proposed. The mechanism of destruction of sodium cyanide with or without ferric oxide addition under various conditions was examined by XRD, DSC-TG, and chemical analysis technologies. In the absence of ferric oxide, sodium cyanide decomposes at 587.4 ℃ in air and 879.2 ℃ in argon atmosphere. In the presence of ferric oxide, about 60% of sodium cyanide decomposes at 350 ℃ for 30 min in argon, while almost all sodium cyanide decomposes within 30 min in air or O2 with mass ratio of ferric oxide to sodium cyanide of 1:1. The increase of ferric oxide addition, temperature, and heating time facilitates the destruction of sodium cyanide. It is believed that with ferric oxide addition, NaCN reacts with Fe2O3 to form Na4Fe(CN)6, Na2CO3, NaNO2 and Fe3O4 in argon. NaCN decomposes into NaCNO, Na4Fe(CN)6, minor NaNO2, and the formed NaCNO and Na4Fe(CN)6 further decompose into Na2CO3, CO2, N2, FeOx, and minor NOx in air or O2.展开更多
Hydrated ferric oxide(HFO)has high adsorption efficiency for As(Ⅲ).However,its high self-aggregation usually reduces the efficiency and limits the scaledup application.Herein,biochar(BC),with large surface area and a...Hydrated ferric oxide(HFO)has high adsorption efficiency for As(Ⅲ).However,its high self-aggregation usually reduces the efficiency and limits the scaledup application.Herein,biochar(BC),with large surface area and amounts of surface functional groups was used to tune the loading and distribution of HFO to prepare an efficient adsorbent(HFO/BC)via in-situ synthesis method.The influence of the mass ratio of iron salt to BC on HFO/BC morphology was investigated,and the mechanism was discussed.The results showed that novel HFO was formed and distributed uniformly on the surface of BC when the mass ratio of iron salt to BC was 5:1.The adsorption kinetics and isotherms studies show that the novel HFO/BC(5:1)composite can fast treat As(Ⅲ)with a high adsorption capacity of 104.55 mg·g^(-1),indicating that it is a potential material for removing arsenic from polluted water.展开更多
A great amount of red mud generated from alumina production by Bayer process was considered as a low-grade iron ore with a grade of 5wt% to 30wt% iron.We adopted the reduction roastingmagnetic separation process to re...A great amount of red mud generated from alumina production by Bayer process was considered as a low-grade iron ore with a grade of 5wt% to 30wt% iron.We adopted the reduction roastingmagnetic separation process to recover ferric oxide from red mud.The red mud samples were processed by reduction roasting,grinding and magnetic separating respectively.The effects of different parameters on the recovery rate of iron were studied in detail.The optimum techqicalparameters were proposed with 700 ℃roasting for 20 min,as 50wt% carbon and 4wt% additive were added.The experimentalresults indicated that the iron recovery and the grade of totaliron were 91% and 60%,respectively.A novelprocess is applicable to recover ferric oxide from the red mud waste fines.展开更多
A hydrometallurgical process for indium extraction and ferric oxide powder preparation for soft magnetic ferrite material was developed. Using reduction lixivium from high-acid reductive leaching of zinc oxide calcine...A hydrometallurgical process for indium extraction and ferric oxide powder preparation for soft magnetic ferrite material was developed. Using reduction lixivium from high-acid reductive leaching of zinc oxide calcine as raw solution, copper and indium were firstly recovered by iron powder cementation and neutralization. The recovery ratios of Cu and In are 99% and 95%, respectively. Some harmful impurities that have negative influences on magnetic properties of soft magnetic ferrite material are deeply removed with sulfidization purification and neutral flocculation method. Under the optimum conditions, the content of impurities like Cu, Pb, As, Al in pure Zn-Fe sulfate solution are less than 0.004 g/L, but those of Cd, Si, Ca and Mg are relatively high. Finally, thermal precipitation of iron is carried out at 210 ℃ for 1.5 h. The precipitation ratio of Fe is 93.33%. Compared with the quality standard of ferric oxide for soft magnetic ferrite materials, the contents of Al and Mg in obtained ferric oxide powder meet the requirement of YHT1 level of ferric oxide, and those of Si, Ca meet the requirement of YHT3 level of ferric oxide. XRD and SEM characterizations confirm that the obtained sample is well-dispersed spindle spherule with regular a-Fe2O3 crystal structure. The length-to-diameter ratio ofa-Fe2O3 powder is （3-4）：1 with an average particle size of 0.5 μm.展开更多
We have studied the genotoxic and apoptotic potential of ferric oxide nanoparticles（Fe_2O_3-NPs） in Raphanus sativus（radish）.Fe_2O_3-NPs retarded the root length and seed germination in radish.Ultrathin sections o...We have studied the genotoxic and apoptotic potential of ferric oxide nanoparticles（Fe_2O_3-NPs） in Raphanus sativus（radish）.Fe_2O_3-NPs retarded the root length and seed germination in radish.Ultrathin sections of treated roots showed subcellular localization of Fe_2O_3-NPs,along with the appearance of damaged mitochondria and excessive vacuolization.Flow cytometric analysis of Fe_2O_3-NPs（1.0 mg/m L） treated groups exhibited 219.5%,161%,120.4% and 161.4% increase in intracellular reactive oxygen species（ROS）,mitochondrial membrane potential（ΔΨm）,nitric oxide（NO） and Ca2＋influx in radish protoplasts.A concentration dependent increase in the antioxidative enzymes glutathione（GSH）,catalase（CAT）,superoxide dismutase（SOD） and lipid peroxidation（LPO） has been recorded.Comet assay showed a concentration dependent increase in deoxyribonucleic acid（DNA） strand breaks in Fe_2O_3-NPs treated groups.Cell cycle analysis revealed 88.4% of cells in sub-G1 apoptotic phase,suggesting cell death in Fe_2O_3-NPs（2.0 mg/m L） treated group.Taking together,the genotoxicity induced by Fe_2O_3-NPs highlights the importance of environmental risk associated with improper disposal of nanoparticles（NPs） and radish can serve as a good indicator for measuring the phytotoxicity of NPs grown in NP-polluted environment.展开更多
A new secondary ore of rare earth was discovered in the Southwest of China. It is a kind of product of the weathered mineral. The rare earth elements (REE) in it exist probably as ionic characteristic adsorption state...A new secondary ore of rare earth was discovered in the Southwest of China. It is a kind of product of the weathered mineral. The rare earth elements (REE) in it exist probably as ionic characteristic adsorption state in manganesian and ferric oxide colloid mineral, and one bearer of REE is amorphous ferric oxide gel. It is neessary to study the binding state of rare earth elements on manganesian and ferric oxide in order to utilize comprehensively the rare earth resources and avoid latent influence on the environment resulting from the fact that highcontent rare earth elements are carried into soil by the mineral efflorescence. A simulating adsorption test of rare earth ions in weak acid media is carried out with ferric oxide gel prepared by sol-gel method. The experimental results show that the characteristics of adsorption isotherm correspond well with the Flory-Huggins equation, but deviated from the Langmuir equation. The standard molar adsorption Gibbs function, standard molar adsorption entropy and standard molar adsorption enthaply are calculated. The measurements of the point of zero charge and isoelectric point show occurrence of the characteristic adsorption. It has been proved that the OH group on the skeleton of ferric oxide gel is the innate cause of the characteristic adsorption.展开更多
Ferric oxides have drawn significant interest due to their unique properties, relatively low cost, and due to their potential applications in different fields. In this work, cobalt (Co) doped iron oxide (Fe2O3) powder...Ferric oxides have drawn significant interest due to their unique properties, relatively low cost, and due to their potential applications in different fields. In this work, cobalt (Co) doped iron oxide (Fe2O3) powders, with crystalline size 36.97 nm were successfully prepared using a microwave- hydrothermal process for the first time and characterised using different techniques. The morphology of the samples was characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive analysis of X-ray spectroscopy (EDAX), Fourier transform infrared (FT-IR) spectroscopy and ultraviolet-visible (UV-Vis) spectroscopy. The images show monodispersed particles with a sharp-edged square morphology. It was found that the average size was about 33.3 nm for Fe2O3 and 36.97 nm for Co-Fe2O3. The Co atomic percentage dopants were approximately 5.73%. The nanosized synthesised materials in this study may find an application in the areas of removal of toxic metal and dyes research.展开更多
An amorphous ferric oxide layer was prepared on a bismuth vanadate photoanode.This resulted in improved charge carrier separation and surface catalytic performance compared with the photoanode without the oxide layer....An amorphous ferric oxide layer was prepared on a bismuth vanadate photoanode.This resulted in improved charge carrier separation and surface catalytic performance compared with the photoanode without the oxide layer.The photocurrent of the oxide‐layer‐containing photoanode was2.52mA/cm2at1.23V versus the reversible hydrogen electrode,in potassium phosphate buffer,(0.5mol/L,pH=7.0).The amorphous ferric oxide layer on the photoanode contained low‐valence‐state iron species(FeII),which enabled efficient hole extraction and transfer.展开更多
With the rapid growing of nanotechnology, the effects of nanomaterials released into the environment on plants have drawn more and more attention. Iron is an element essential for plant growth and development. Iron is...With the rapid growing of nanotechnology, the effects of nanomaterials released into the environment on plants have drawn more and more attention. Iron is an element essential for plant growth and development. Iron is involved in chlorophyll formation;iron deficiency will cause a plant disorder known as chlorosis. However, whether iron in nano-ferric oxide can be absorbed by plants were rarely concerned. Nano-ferric oxide might promote the growth and development of plants in a suitable concentration. An experiment was designed to evaluate whether nano-ferric oxide can be used to treat chlorosis and the physiological changes of plants in nano-ferric oxide environment. Watermelon was chosen as the experimental plant. Seedlings of watermelon plants were grown in full nutrient solution without iron for 2 weeks until the leaves got yellow. Then the seedlings were treated with different concentrations of nano-ferric oxide (0, 20, 50, 100 mg/L) and 50 mmol/L of EDTA-Fe(II) for a month. The control group seedlings were still grown in full nutrient solution without any iron. Indicators such as activity of antioxidase like superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and content of malondialdehyde (MDA) and soluble protein were studied to measure the physiological effects nano-ferric oxide might have on watermelon. It was observed that the leaves reverted green. Experimental data showed that watermelon absorbed iron from nano-ferric oxide, and nano-ferric oxide promoted watermelon growth in some ways in a suitable concentration.展开更多
The process of dehydrogenation of methyl butenes to isoprene is conducted in the presence of iron oxide catalysts whose composition may include oxides of alkaline metals, alkaline earth metals, and transition metals. ...The process of dehydrogenation of methyl butenes to isoprene is conducted in the presence of iron oxide catalysts whose composition may include oxides of alkaline metals, alkaline earth metals, and transition metals. Catalysts of latest generation can also contain oxides of rare earth elements, particularly cerium oxide. However there is no any common opinion concerning its effect on catalytic properties of iron oxide catalysts. It is well known that ceric oxide has a positive effect on the quantity and stability of active centers and can play a critical role in a redox cycle of the dehydrogenation process. By means of differential thermal analysis, dispersion analysis and X-ray phase analysis, it was found in present study that introducing of ceric oxide promotes the decrease in hematite crystallite sizes. At the same time, it prevents potassium polyferrites formation, with the equilibrium of topochemical reaction between ferric oxide and po tassium carbonates moving predominantly to the formation of intermediate products–monoferrite systems, having greater catalytic activity. The increase in potassium monoferrite content results in dispersion of particles in the Fe2O3-K2CO3-СеО2 system that is accompanied by modification of texture characteristics. For this catalyst composition, the optimum concentration of ceric oxide (8.7 wt.%), leading to the formation of a certain ratio of mono- and polyferrite phases, was found. If more than 8.7 wt.% of СеО2 is introduced, the modification of texture characteristics of catalyst samples takes place, that negatively affects their selectivity.展开更多
The efficient separation of chalcopyrite(CuFeS2)and galena(PbS)is essential for optimal resource utilization.However,find-ing a selective depressant that is environmentally friendly and cost effective remains a challe...The efficient separation of chalcopyrite(CuFeS2)and galena(PbS)is essential for optimal resource utilization.However,find-ing a selective depressant that is environmentally friendly and cost effective remains a challenge.Through various techniques,such as mi-croflotation tests,Fourier transform infrared spectroscopy,scanning electron microscopy(SEM)observation,X-ray photoelectron spec-troscopy(XPS),and Raman spectroscopy measurements,this study explored the use of ferric ions(Fe^(3+))as a selective depressant for ga-lena.The results of flotation tests revealed the impressive selective inhibition capabilities of Fe^(3+)when used alone.Surface analysis showed that Fe^(3+)significantly reduced the adsorption of isopropyl ethyl thionocarbamate(IPETC)on the galena surface while having a minimal impact on chalcopyrite.Further analysis using SEM,XPS,and Raman spectra revealed that Fe^(3+)can oxidize lead sulfide to form compact lead sulfate nanoparticles on the galena surface,effectively depressing IPETC adsorption and increasing surface hydrophilicity.These findings provide a promising solution for the efficient and environmentally responsible separation of chalcopyrite and galena.展开更多
Micaceous iron oxide （MIO） with a hexagonal flaky shape was prepared by hydrothermal method. The ferric hydroxide used as precursor was obtained by an acidic leaching solution of pyrite cinders reacting with ammonia...Micaceous iron oxide （MIO） with a hexagonal flaky shape was prepared by hydrothermal method. The ferric hydroxide used as precursor was obtained by an acidic leaching solution of pyrite cinders reacting with ammonia solution. The optimal experimental conditions for preparing micaceous iron oxide were investigated by orthogonal experiments. Micaceous iron oxide can be successfully prepared when optimal parameters of total iron concentration of 2.0 mol/L, pH value of 8, n（Fe2＋）/n（Fe3＋） of 0.1, mass of seed crystal of 1 g, reaction temperature of 260 ℃ and reaction time of 30 min are applied. X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and selected area electron diffractometry （SAEM） were adopted to characterize the hydrothermal products prepared under optimal conditions. The results indicate that highly crystallized α-Fe2O3 hexagonal flakes, about 1.0-1.5 μm in diameter and 0.1 μm in thickness, are prepared. Furthermore, the quality of micaceous iron oxide prepared can meet the required characteristics of micaceous iron oxide pigments for paints （ISO 10601--2007）.展开更多
We focused on the need for the phosphorus removal in water plant process. As for surface water plant, the enhancement of phosphorus removal in purification process can raise the biological stability of effluent potabl...We focused on the need for the phosphorus removal in water plant process. As for surface water plant, the enhancement of phosphorus removal in purification process can raise the biological stability of effluent potable water. This study conducted the effect of two water treatment processes for phosphorus removal, including the PAC + AAL (the treatment process using poly aluminum chloride and activated aluminum oxide) and PFS + AAL (the treatment process using poly ferric sulfate and activated aluminum oxide). The aim is to use the adsorption capacity of activated aluminum oxide to increase the removal of phosphorus in filtration process. The result showed that the two processes both can remove the phosphorus concentration to reach below 10 μg/L, and the PAC + AAL is the better process.展开更多
Experiments on the solid-state reaction between iron ore particles and MgO were performed to investigate the coating mechanism of MgO on the iron ore particles＇ surface during fluidized bed reduction. MgO powders and...Experiments on the solid-state reaction between iron ore particles and MgO were performed to investigate the coating mechanism of MgO on the iron ore particles＇ surface during fluidized bed reduction. MgO powders and iron ore particles were mixed and compressed into briquettes and, subsequently, roasted at different temperatures and for different time periods. A Mg-containing layer was observed on the outer edge of the iron ore particles when the roasting temperature was greater than 1173 K. The concentration of Fe in the Mg-containing layer was evenly distributed and was approximately 10wt%, regardless of the temperature change. Boundary layers of Mg and Fe were observed outside of the iron ore particles. The change in concentration of Fe in the boundary layers was simulated using a gas–solid diffusion model, and the diffusion coefficients of Fe and Mg in these layers at different temperatures were calculated. The diffusion activation energies of Fe and Mg in the boundary layers in these experiments were evaluated to be approximately 176 and 172 k J/mol, respectively.展开更多
基金supported by the Capacity Building Project of Local University of Shanghai Municipal Science and Technology Commission(No.10230502900)the Program for Shanghai Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture animals(No.2021-KJ-02-12)the Innovation Project for Chongming Agriculture Industry from Chongming District Agriculture Commission of Shanghai(No.2022CNKC-01-05).
文摘The effectiveness of Elodea nuttallii combined with a mixture of hydrous ferric oxide,zeolite and calcite(HZC)to reduce the internal loading of phosphorus(P)from sediment and its mechanism were studied,and the effect of Elodea nuttallii combined with HZC on the composition and function of the microbial communities in the surface sediment was also investigated.The results showed that the combination utilization of Elodea nuttallii and HZC can decrease the risk of phosphorus liberation from sediment to the overlying water,and the controlling efficiency of Elodea nuttallii combined with HZCwas higher than that of Elodea nuttallii or HZC alone.The passivation of labile P measured by diffusive gradient in thin film device and mobile P played a crucial role in the control of internal P loading from sediment by the combined Elodea nuttallii+HZC treatment.HZC capping had a promoting effect on the growth of Elodea nuttallii.This was beneficial to the absorption of phosphorus from sediment by Elodea nuttallii.The combined application of Elodea nuttallii and HZC not only had a certain negative effect on the diversity of bacteria in the surface sediment,but also changed themicrobial compositions of the surface sediment at the levels of phylum and genus.However,the microbial communities in the surface sediment still can perform good ecological function.The above results suggest that the combined application of Elodea nuttallii and HZC has a high potential in the management of internal P loading from sediment.
基金Project(51374239)supported by the National Natural Science Foundation of China
文摘Digesting aluminum-bearing minerals and converting ferric oxide to magnetite simultaneously in Bayer digestion process is crucially important to deal with high-iron diasporic bauxite economically for alumina production.The reaction behaviors of hydrothermal reduction of ferric oxide in alkali solution were studied by both thermodynamic calculation and experimental investigation.The thermodynamic calculation indicates that Fe3O4 can be formed by the conversion of Fe2O3 at proper redox potentials in alkaline solution.The experimental results show that the formation ratio of Fe3O4 either through the reaction of Fe and Fe2O3 or through the reaction of Fe and H2O in alkaline aqueous solution increases remarkably with raising the temperature and alkali concentration,suggesting that Fe（OH）3- and Fe（OH）4- form by dissolving Fe and Fe2O3,respectively,in alkaline aqueous solution and further react to form Fe3O4.Moreover,aluminate ions have little influence on the hydrothermal reduction of Fe2O3 in alkaline aqueous solution,and converting iron minerals to magnetite can be realized in the Bayer digestion process of diasporic bauxite.
基金Project(51274243)supported by the National Natural Science Foundation of China
文摘Pure compounds and kaolin were employed to investigate the reaction behavior of ferric oxide in thetrinarysystem Fe2O3?SiO2?Al2O3 during reductive sintering process. The thermodynamic analyses and reductive sintering experimental results show that ferrous oxide generated from the reduction of ferric oxide by carbon can react with silicon dioxide and aluminum oxide to form ferrous silicate and hercynite at 1173 K, respectively. In the trinary system Fe2O3?SiO2?Al2O3, ferrous oxide obtained from ferric oxide reduction preferentially reacts with aluminum oxide to form hercynite, and the reaction of ferrous oxide with silicon dioxide occurs only when there is surplus ferrous oxide after the exhaustion of aluminum oxide. When sintering temperature rises to 1473 K, hercynite further reacts with silicon dioxide to form mullite and ferrous oxide. Results presented in this work may throw a new light upon the separation of alumina and silica present in Al/Fe-bearing materials with low mass ratio of alumina to silica in alumina production.
基金supported by the National Natural Science Foundation of China(No.21177059)the Depart-ment of Science and Technology,Jiangsu Province(No.BK2012017/2011016,BE2012160)
文摘We fabricated and characterized two hybrid adsorbents originated from hydrated ferric oxides （HFOs） using a polymeric anion exchanger D201 and calcite as host. The resultant adsorbents （denoted as HFO-201 and IOCCS） were employed for Sb（V） removal from water. Increasing solution pH from 3 to 9 apparently weakened Sb（V） removal by both composites, while increasing temperature from 293 to 313 K only improved Sb（V） uptake by IOCCS. HFO-201 exhibited much higher capacity for Sb（V） than for IOCCS in the absence of other anions in solution. Increasing ionic strength from 0.01 to 0.1 mol/L NaNO3 would result in a significant drop of the capacity of HFO-201 in the studied pH ranges; however, negligible effect was observed for 1OCCS under similar conditions. Similarly, the competing chloride and sulfate pose more negative effect on Sb（V） adsorption by HFO-201 than by IOCCS, and the presence of silicate greatly decreased their adsorption simultaneously, while calcium ions were found to promote the adsorption of both adsorbents. XPS analysis further demonstrated that preferable Sb（V） adsorption by both hybrids was attributed to the inner sphere complexation of Sb（V） and HFO, and Ca（II） induced adsorption enhancement possibly resulted from the formation of HFO-Ca-Sb complexes. Column adsorption runs proved that Sb（V） in the synthetic water could be effectively removed from 30 μg/L to below 5μg/L （the drinking water standard regulated by China）, and the effective treatable volume of IOCCS was around 6 times as that of HFO-201, implying that HFO coatings onto calcite might be a more effective approach than immobilization inside D201.
基金financial supports from the National Key R&D Program of China (2018YFC0604604)the National Natural Science Foundation of China-Yunnan Joint Fund (U1702252)+1 种基金the Fundamental Research Funds for Central Universities of China (N182506003)the Key Scientific Research Project of Liaoning Province,China (2019JH2/10300051)。
文摘Efficient destruction of cyanide by thermal decomposition with ferric oxide addition was proposed. The mechanism of destruction of sodium cyanide with or without ferric oxide addition under various conditions was examined by XRD, DSC-TG, and chemical analysis technologies. In the absence of ferric oxide, sodium cyanide decomposes at 587.4 ℃ in air and 879.2 ℃ in argon atmosphere. In the presence of ferric oxide, about 60% of sodium cyanide decomposes at 350 ℃ for 30 min in argon, while almost all sodium cyanide decomposes within 30 min in air or O2 with mass ratio of ferric oxide to sodium cyanide of 1:1. The increase of ferric oxide addition, temperature, and heating time facilitates the destruction of sodium cyanide. It is believed that with ferric oxide addition, NaCN reacts with Fe2O3 to form Na4Fe(CN)6, Na2CO3, NaNO2 and Fe3O4 in argon. NaCN decomposes into NaCNO, Na4Fe(CN)6, minor NaNO2, and the formed NaCNO and Na4Fe(CN)6 further decompose into Na2CO3, CO2, N2, FeOx, and minor NOx in air or O2.
基金the National Natural Science Foundation of China(No.52173208)the Priority Academic Program Development of Jiangsu Higher Education Institutions and Qing Lan Project of Yangzhou University(Dr.LJL)。
文摘Hydrated ferric oxide(HFO)has high adsorption efficiency for As(Ⅲ).However,its high self-aggregation usually reduces the efficiency and limits the scaledup application.Herein,biochar(BC),with large surface area and amounts of surface functional groups was used to tune the loading and distribution of HFO to prepare an efficient adsorbent(HFO/BC)via in-situ synthesis method.The influence of the mass ratio of iron salt to BC on HFO/BC morphology was investigated,and the mechanism was discussed.The results showed that novel HFO was formed and distributed uniformly on the surface of BC when the mass ratio of iron salt to BC was 5:1.The adsorption kinetics and isotherms studies show that the novel HFO/BC(5:1)composite can fast treat As(Ⅲ)with a high adsorption capacity of 104.55 mg·g^(-1),indicating that it is a potential material for removing arsenic from polluted water.
基金Funded by the Fundamental Research Funds for the Central Universities(No.310827151063)the Provincial Training Program of Innovation and Entrepreneurship for Undergraduates(No.201510710134)
文摘A great amount of red mud generated from alumina production by Bayer process was considered as a low-grade iron ore with a grade of 5wt% to 30wt% iron.We adopted the reduction roastingmagnetic separation process to recover ferric oxide from red mud.The red mud samples were processed by reduction roasting,grinding and magnetic separating respectively.The effects of different parameters on the recovery rate of iron were studied in detail.The optimum techqicalparameters were proposed with 700 ℃roasting for 20 min,as 50wt% carbon and 4wt% additive were added.The experimentalresults indicated that the iron recovery and the grade of totaliron were 91% and 60%,respectively.A novelprocess is applicable to recover ferric oxide from the red mud waste fines.
基金Project(50674104) supported by the National Natural Science Foundation of ChinaProject(2006BA02B04-4-2) supported by the Planned Science and Technology of China
文摘A hydrometallurgical process for indium extraction and ferric oxide powder preparation for soft magnetic ferrite material was developed. Using reduction lixivium from high-acid reductive leaching of zinc oxide calcine as raw solution, copper and indium were firstly recovered by iron powder cementation and neutralization. The recovery ratios of Cu and In are 99% and 95%, respectively. Some harmful impurities that have negative influences on magnetic properties of soft magnetic ferrite material are deeply removed with sulfidization purification and neutral flocculation method. Under the optimum conditions, the content of impurities like Cu, Pb, As, Al in pure Zn-Fe sulfate solution are less than 0.004 g/L, but those of Cd, Si, Ca and Mg are relatively high. Finally, thermal precipitation of iron is carried out at 210 ℃ for 1.5 h. The precipitation ratio of Fe is 93.33%. Compared with the quality standard of ferric oxide for soft magnetic ferrite materials, the contents of Al and Mg in obtained ferric oxide powder meet the requirement of YHT1 level of ferric oxide, and those of Si, Ca meet the requirement of YHT3 level of ferric oxide. XRD and SEM characterizations confirm that the obtained sample is well-dispersed spindle spherule with regular a-Fe2O3 crystal structure. The length-to-diameter ratio ofa-Fe2O3 powder is （3-4）：1 with an average particle size of 0.5 μm.
基金funded by the National Plan for Science,Technology and Innovation(MAARIFAH)King Abdul Aziz City for Science and Technology,Kingdom of Saudi Arabia,award number 12-BIO2919-02
文摘We have studied the genotoxic and apoptotic potential of ferric oxide nanoparticles（Fe_2O_3-NPs） in Raphanus sativus（radish）.Fe_2O_3-NPs retarded the root length and seed germination in radish.Ultrathin sections of treated roots showed subcellular localization of Fe_2O_3-NPs,along with the appearance of damaged mitochondria and excessive vacuolization.Flow cytometric analysis of Fe_2O_3-NPs（1.0 mg/m L） treated groups exhibited 219.5%,161%,120.4% and 161.4% increase in intracellular reactive oxygen species（ROS）,mitochondrial membrane potential（ΔΨm）,nitric oxide（NO） and Ca2＋influx in radish protoplasts.A concentration dependent increase in the antioxidative enzymes glutathione（GSH）,catalase（CAT）,superoxide dismutase（SOD） and lipid peroxidation（LPO） has been recorded.Comet assay showed a concentration dependent increase in deoxyribonucleic acid（DNA） strand breaks in Fe_2O_3-NPs treated groups.Cell cycle analysis revealed 88.4% of cells in sub-G1 apoptotic phase,suggesting cell death in Fe_2O_3-NPs（2.0 mg/m L） treated group.Taking together,the genotoxicity induced by Fe_2O_3-NPs highlights the importance of environmental risk associated with improper disposal of nanoparticles（NPs） and radish can serve as a good indicator for measuring the phytotoxicity of NPs grown in NP-polluted environment.
文摘A new secondary ore of rare earth was discovered in the Southwest of China. It is a kind of product of the weathered mineral. The rare earth elements (REE) in it exist probably as ionic characteristic adsorption state in manganesian and ferric oxide colloid mineral, and one bearer of REE is amorphous ferric oxide gel. It is neessary to study the binding state of rare earth elements on manganesian and ferric oxide in order to utilize comprehensively the rare earth resources and avoid latent influence on the environment resulting from the fact that highcontent rare earth elements are carried into soil by the mineral efflorescence. A simulating adsorption test of rare earth ions in weak acid media is carried out with ferric oxide gel prepared by sol-gel method. The experimental results show that the characteristics of adsorption isotherm correspond well with the Flory-Huggins equation, but deviated from the Langmuir equation. The standard molar adsorption Gibbs function, standard molar adsorption entropy and standard molar adsorption enthaply are calculated. The measurements of the point of zero charge and isoelectric point show occurrence of the characteristic adsorption. It has been proved that the OH group on the skeleton of ferric oxide gel is the innate cause of the characteristic adsorption.
文摘Ferric oxides have drawn significant interest due to their unique properties, relatively low cost, and due to their potential applications in different fields. In this work, cobalt (Co) doped iron oxide (Fe2O3) powders, with crystalline size 36.97 nm were successfully prepared using a microwave- hydrothermal process for the first time and characterised using different techniques. The morphology of the samples was characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive analysis of X-ray spectroscopy (EDAX), Fourier transform infrared (FT-IR) spectroscopy and ultraviolet-visible (UV-Vis) spectroscopy. The images show monodispersed particles with a sharp-edged square morphology. It was found that the average size was about 33.3 nm for Fe2O3 and 36.97 nm for Co-Fe2O3. The Co atomic percentage dopants were approximately 5.73%. The nanosized synthesised materials in this study may find an application in the areas of removal of toxic metal and dyes research.
基金supported by the National Natural Science Foundation of China(21373083,21573068)Program of Shanghai Subject Chief Scientist(15XD1501300)+1 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education MinistryScience Technology Commission of Shanghai Municipality(14JC1490900)~~
文摘An amorphous ferric oxide layer was prepared on a bismuth vanadate photoanode.This resulted in improved charge carrier separation and surface catalytic performance compared with the photoanode without the oxide layer.The photocurrent of the oxide‐layer‐containing photoanode was2.52mA/cm2at1.23V versus the reversible hydrogen electrode,in potassium phosphate buffer,(0.5mol/L,pH=7.0).The amorphous ferric oxide layer on the photoanode contained low‐valence‐state iron species(FeII),which enabled efficient hole extraction and transfer.
文摘With the rapid growing of nanotechnology, the effects of nanomaterials released into the environment on plants have drawn more and more attention. Iron is an element essential for plant growth and development. Iron is involved in chlorophyll formation;iron deficiency will cause a plant disorder known as chlorosis. However, whether iron in nano-ferric oxide can be absorbed by plants were rarely concerned. Nano-ferric oxide might promote the growth and development of plants in a suitable concentration. An experiment was designed to evaluate whether nano-ferric oxide can be used to treat chlorosis and the physiological changes of plants in nano-ferric oxide environment. Watermelon was chosen as the experimental plant. Seedlings of watermelon plants were grown in full nutrient solution without iron for 2 weeks until the leaves got yellow. Then the seedlings were treated with different concentrations of nano-ferric oxide (0, 20, 50, 100 mg/L) and 50 mmol/L of EDTA-Fe(II) for a month. The control group seedlings were still grown in full nutrient solution without any iron. Indicators such as activity of antioxidase like superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and content of malondialdehyde (MDA) and soluble protein were studied to measure the physiological effects nano-ferric oxide might have on watermelon. It was observed that the leaves reverted green. Experimental data showed that watermelon absorbed iron from nano-ferric oxide, and nano-ferric oxide promoted watermelon growth in some ways in a suitable concentration.
文摘The process of dehydrogenation of methyl butenes to isoprene is conducted in the presence of iron oxide catalysts whose composition may include oxides of alkaline metals, alkaline earth metals, and transition metals. Catalysts of latest generation can also contain oxides of rare earth elements, particularly cerium oxide. However there is no any common opinion concerning its effect on catalytic properties of iron oxide catalysts. It is well known that ceric oxide has a positive effect on the quantity and stability of active centers and can play a critical role in a redox cycle of the dehydrogenation process. By means of differential thermal analysis, dispersion analysis and X-ray phase analysis, it was found in present study that introducing of ceric oxide promotes the decrease in hematite crystallite sizes. At the same time, it prevents potassium polyferrites formation, with the equilibrium of topochemical reaction between ferric oxide and po tassium carbonates moving predominantly to the formation of intermediate products–monoferrite systems, having greater catalytic activity. The increase in potassium monoferrite content results in dispersion of particles in the Fe2O3-K2CO3-СеО2 system that is accompanied by modification of texture characteristics. For this catalyst composition, the optimum concentration of ceric oxide (8.7 wt.%), leading to the formation of a certain ratio of mono- and polyferrite phases, was found. If more than 8.7 wt.% of СеО2 is introduced, the modification of texture characteristics of catalyst samples takes place, that negatively affects their selectivity.
基金the National Natural Science Foundation of China(Nos.52204298 and 52004335)the National Key R&D Program of China(Nos.2022YFC2904502 and 2022YFC2904501)+1 种基金the Major Science and Technology Projects in Yunnan Province(No.202202AB080012)the Science Research Initiation Fund of Central South University(No.202044019).
文摘The efficient separation of chalcopyrite(CuFeS2)and galena(PbS)is essential for optimal resource utilization.However,find-ing a selective depressant that is environmentally friendly and cost effective remains a challenge.Through various techniques,such as mi-croflotation tests,Fourier transform infrared spectroscopy,scanning electron microscopy(SEM)observation,X-ray photoelectron spec-troscopy(XPS),and Raman spectroscopy measurements,this study explored the use of ferric ions(Fe^(3+))as a selective depressant for ga-lena.The results of flotation tests revealed the impressive selective inhibition capabilities of Fe^(3+)when used alone.Surface analysis showed that Fe^(3+)significantly reduced the adsorption of isopropyl ethyl thionocarbamate(IPETC)on the galena surface while having a minimal impact on chalcopyrite.Further analysis using SEM,XPS,and Raman spectra revealed that Fe^(3+)can oxidize lead sulfide to form compact lead sulfate nanoparticles on the galena surface,effectively depressing IPETC adsorption and increasing surface hydrophilicity.These findings provide a promising solution for the efficient and environmentally responsible separation of chalcopyrite and galena.
基金Project(2008A090300016) supported by Major Science & Technology Special Program of Guangdong Province,China
文摘Micaceous iron oxide （MIO） with a hexagonal flaky shape was prepared by hydrothermal method. The ferric hydroxide used as precursor was obtained by an acidic leaching solution of pyrite cinders reacting with ammonia solution. The optimal experimental conditions for preparing micaceous iron oxide were investigated by orthogonal experiments. Micaceous iron oxide can be successfully prepared when optimal parameters of total iron concentration of 2.0 mol/L, pH value of 8, n（Fe2＋）/n（Fe3＋） of 0.1, mass of seed crystal of 1 g, reaction temperature of 260 ℃ and reaction time of 30 min are applied. X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and selected area electron diffractometry （SAEM） were adopted to characterize the hydrothermal products prepared under optimal conditions. The results indicate that highly crystallized α-Fe2O3 hexagonal flakes, about 1.0-1.5 μm in diameter and 0.1 μm in thickness, are prepared. Furthermore, the quality of micaceous iron oxide prepared can meet the required characteristics of micaceous iron oxide pigments for paints （ISO 10601--2007）.
文摘We focused on the need for the phosphorus removal in water plant process. As for surface water plant, the enhancement of phosphorus removal in purification process can raise the biological stability of effluent potable water. This study conducted the effect of two water treatment processes for phosphorus removal, including the PAC + AAL (the treatment process using poly aluminum chloride and activated aluminum oxide) and PFS + AAL (the treatment process using poly ferric sulfate and activated aluminum oxide). The aim is to use the adsorption capacity of activated aluminum oxide to increase the removal of phosphorus in filtration process. The result showed that the two processes both can remove the phosphorus concentration to reach below 10 μg/L, and the PAC + AAL is the better process.
基金supported by the Fundamental Research Funds for the Central Universities (FRF-TP-15-009A2)the Project Funded by China Postdoctoral Science Foundation (2015M570931)+1 种基金the National Natural Science Fund Project of China (91534121)the National Major Scientific Instruments Special Plan (2011YQ12003907)
文摘Experiments on the solid-state reaction between iron ore particles and MgO were performed to investigate the coating mechanism of MgO on the iron ore particles＇ surface during fluidized bed reduction. MgO powders and iron ore particles were mixed and compressed into briquettes and, subsequently, roasted at different temperatures and for different time periods. A Mg-containing layer was observed on the outer edge of the iron ore particles when the roasting temperature was greater than 1173 K. The concentration of Fe in the Mg-containing layer was evenly distributed and was approximately 10wt%, regardless of the temperature change. Boundary layers of Mg and Fe were observed outside of the iron ore particles. The change in concentration of Fe in the boundary layers was simulated using a gas–solid diffusion model, and the diffusion coefficients of Fe and Mg in these layers at different temperatures were calculated. The diffusion activation energies of Fe and Mg in the boundary layers in these experiments were evaluated to be approximately 176 and 172 k J/mol, respectively.
