The surface oxidation patterns of iron or low-carbon steels are critical to their life when serving in typical damp environments. An accurate determination of the oxidation pattern entails tracking the iron atoms oxid...The surface oxidation patterns of iron or low-carbon steels are critical to their life when serving in typical damp environments. An accurate determination of the oxidation pattern entails tracking the iron atoms oxidized at the iron/steel-moisture interface. Using a quantum chemistry-based force field that is capable of simulating chemical reactions, this paper studies the process of iron oxidation under a typical moist condition. The oxidation of iron surface was found to be highly thermodynamic and dependent on the availability of reactants. A triplex structure was formed at the end of a three-stage oxidation process to reduce the overall oxidation speed. The results from this study shed light on the atomistic mechanism of iron oxidation; therefore can be used to guide the protection of general ferrous-based iron/steel structures.展开更多
The abiotic oxidation of divalentmanganese(Mn(Ⅱ))and the formation of Mn oxides are important geochemical processes,which control the mobility and availability of Mn as well as element cycling and pollutant behavior ...The abiotic oxidation of divalentmanganese(Mn(Ⅱ))and the formation of Mn oxides are important geochemical processes,which control the mobility and availability of Mn as well as element cycling and pollutant behavior in soils.It was found that iron(oxyhydr)oxides can catalyze Mn(Ⅱ)oxidation,but the effects of the coexisting dissolved organic matter(DOM)molecules on the catalysis of different iron(oxyhydr)oxides for Mn(Ⅱ)oxidation are poorly understood.Herein,we investigated Mn(Ⅱ)oxidation under the impacts of the interactions between iron(oxyhydr)oxides(i.e.,ferrihydrite,goethite and hematite)and DOM molecules.Simultaneously,we elucidated the variations of DOM composition and properties.Our results indicated that the catalysis of iron(oxyhydr)oxides for Mn(Ⅱ)oxidation was significantly inhibited by DOM.Moreover,DOM had less inhibiting effect on the catalysis of ferrihydrite for Mn(Ⅱ)oxidation and the formation of Mn oxides(e.g.,hausmannite and buserite)relative to goethite and hematite,whichwas partially because of the higher electron transfer capacities of ferrihydrite.Meanwhile,DOM molecules with high nominal oxidation state of carbon(NOSC),molecular weight,unsaturation and aromaticity were selectively adsorbed and oxidized by Mn oxides,including the oxygenated phenols and polyphenols.The newly formed molecules mainly belonged to phenols depleted of oxygen and aliphatics.Furthermore,NOSC was a key molecular characteristic for controlling DOM composition during DOM adsorption and oxidation by Mn oxides when iron minerals were present.Overall,our research contributes to understanding Mn(Ⅱ)oxidation mechanisms under heterogeneous systems and behaviors of DOM molecules in the environment.展开更多
Both soil organic carbon (SOC) and iron (Fe) oxide content, among other factors, drive the formation and stability of soil aggregates.However, the mechanism of these drivers in greenhouse soil fertilized with organic ...Both soil organic carbon (SOC) and iron (Fe) oxide content, among other factors, drive the formation and stability of soil aggregates.However, the mechanism of these drivers in greenhouse soil fertilized with organic fertilizer is not well understood.In a 3-year field experiment, we aimed to investigate the factors which drive the stability of soil aggregates in greenhouse soil.To explore the impact of organic fertilizer on soil aggregates, we established four treatments:no fertilization (CK);inorganic fertilizer (CF);organic fertilizer (OF);and combined application of inorganic and organic fertilizers(COF).The application of organic fertilizer significantly enhanced the stability of aggregates, that is it enhanced the mean weight diameter, geometric mean diameter and aggregate content (%) of>0.25 mm aggregate fractions.OF and COF treatments increased the concentration of SOC, especially the aliphatic-C, aromatic-C and polysaccharide-C components of SOC, particularly in>0.25 mm aggregates.Organic fertilizer application significantly increased the content of free Fe(Fed), reactive Fe (Feo), and non-crystalline Fe in both bulk soil and aggregates.Furthermore, non-crystalline Fe showed a positive correlation with SOC content in both bulk soil and aggregates.Both non-crystalline Fe and SOC were significantly positively correlated with>2 mm mean weight diameter.Overall, we believe that the increase of SOC, aromatic-C, and non-crystal ine Fe concentrations in soil after the application of organic fertilizer is the reason for improving soil aggregate stability.展开更多
The efficiency and mechanism of hydrous iron oxide(HFO)and HFO/calcite mixture to inactivate the phosphorus in the overlying water(OW)/sediment system under the feed adding condition were explored,and the effect of HF...The efficiency and mechanism of hydrous iron oxide(HFO)and HFO/calcite mixture to inactivate the phosphorus in the overlying water(OW)/sediment system under the feed adding condition were explored,and the effect of HFO and HFO/calcite mixture addition on the diversity,composition and function of bacterial communities in the sediment was examined.HFO and HFO/calcite mixture direct addition can effectively lower the concentration of soluble reactive phosphorus(RSP)and diffusion gradient in thin film-unstable phosphorus(PD GT)in OW and inactivate the P DGTin the upper sediment.The elimination efficiencies of RSP by the direct HFO and HFO/calcite mixture addition were 48.9%-97.0%and 42.4%-95.4%,respectively.The alteration in the addition mode from the one-time to multiple direct addition was beneficial to the immobilization of RSP and PD GTin OW and P DGTin the upper sediment by HFO and HFO/calcite mixture under the feed input condition in the long run.Permeable fabric wrapping reduced the inactivation efficiency of RSP in OW by HFO and HFO/calcite mixture,but it made the recycling of these materials possible.Most of P immobilized by HFO and HFO/calcite mixture was relatively or very stable.After the HFO and HFO/calcite mixture addition,the composition of bacterial communities in the surface sediment changed.However,the bacterial communities in the amended sediments still can perform good ecological function.Our findings suggest that HFO and HFO/calcite mixture are promising phosphorus-immobilization materials for the inactivation of RSP and PD GTin OW and PD GTin the upper sediment under the feed inputting condition.展开更多
The conversion of subtropical red soils into farmland involves complex transformations of iron oxides.Investigating iron mineralogy can enhance understanding of magnetic minerals in relation to soil formation on farml...The conversion of subtropical red soils into farmland involves complex transformations of iron oxides.Investigating iron mineralogy can enhance understanding of magnetic minerals in relation to soil formation on farmland in subtropical regions.In this study,we investigated the properties of iron oxide and its environmental implications in the farmland of Meizhou city,Guangdong province.The results showed that farmland soils had higher magnetism than the red soils developed from the same metamorphic rock.The red soils displayed significantly higher concentrations of goethite and hematite than the farmland soils.The dominant factor influencing the magnetic changes in farmland and red soils was the concentration of fine-grained ferromagnetic minerals.Red soil magnetism is an indicator of soil weathering intensity,whereas farmland soil magnetism is closely related to human cultivation activities.In contrast to the red soils,the farmland soils lacked the pronounced transformation of ferromagnetic minerals into hematite and goethite.A vigorous oxidation process catalyzes the transformation of strong magnetic minerals into significant amounts of hematite and goethite,which promotes the reduced magnetism of red soils.The conversion of red soils into farmland soils initially increased the accumulation of ferromagnetic materials due to cultivation processes.However,long-term cultivation led to the gradual loss of fine-grained ferromagnetic minerals,while goethite and lepidocrocite became the dominant magnetic mineral types.展开更多
Magnetic iron oxide nanoparticles(Fe_(x)O_(y) NPs,mainly Fe3O4 andγ-Fe2O_(3))are nanomaterials ubiquitously present in aquatic,terrestrial,and atmospheric environments,with a high prevalence and complex sources.Over ...Magnetic iron oxide nanoparticles(Fe_(x)O_(y) NPs,mainly Fe3O4 andγ-Fe2O_(3))are nanomaterials ubiquitously present in aquatic,terrestrial,and atmospheric environments,with a high prevalence and complex sources.Over the past decade,numerous reports have emerged on the presence of exogenous particles in human body,facilitated by the rapid development of separation and detection methods.The health risk associated with magnetic Fe_(x)O_(y) NP have garnered escalating attention due to their presence in human blood and brain tissues,especially for their potential association with neurodegenerative diseases like Alzheimer’s disease.In this paper,we provide a comprehensive overview of sources,analysis methods,environmental impacts,and health risks of magnetic Fe_(x)O_(y) NP.Currently,most researches are primarily based on engineered Fe_(x)O_(y) NP,while reports aboutmagnetic Fe_(x)O_(y) NP existing in real-world environments are still limited,especially for their occurrence levels in various environmental matrices,environmental transformation behavior,and biotoxic effects.Our study reviews this emerging pollutant,providing insights to address current research deficiencies and chart the course for future studies.展开更多
Early diagnosis and accurate boundary delineation are the key steps of tumor precision medicine.Circulating tumor cells(CTCs)detection of liquid biopsy can provide abundant information for early diagnosis of cancer.Hi...Early diagnosis and accurate boundary delineation are the key steps of tumor precision medicine.Circulating tumor cells(CTCs)detection of liquid biopsy can provide abundant information for early diagnosis of cancer.High detection specificity and good enrichment features are two key factors for CTCs accurate identification in peripheral blood sample.For this purpose,iron oxide(IO)-based surface-enhanced Raman scattering(SERS)bioprobes with good biocompatibility,high detection sensitivity,remarkable detection specificity,and good enrichment efficiency,were developed for detecting different types of CTCs.Magnetic SERS bioprobes combined with programmed death ligand-1(PD-L1)antibody are regarded as an effective way to boost the targeting ability and detection specificity,benefiting for accurately capturing and identifying rare CTCs.Four types of CTCs with different PD-L1 expression were accurately distinguished among white blood cells via high-resolution SERS mapping images and stable Raman signals.Subsequently,CTCs blood samples obtained from the triple negative breast cancer patients were also successfully recognized compared to that of health people,indicating IO@AR@PDA-a PD-L1 SERS bioprobe possessed great potential for CTCs detection in liquid biopsy.Additionally,IO-based bioprobe exhibited excellent dual-modal imaging abilities of high-resolution SERS imaging mode and microimaging magnetic resonance imaging mode.These two highly complementary imaging modes endowed IO-based bioprobes unrivalled capacity in tumor boundary differentiation,supporting tumor accurate resection and precise surgery.To our best knowledge,this is the first time that biocompatible IO-based SERS bioprobes without noble metal element were reported not only for CTCs accurate detection,but also for precise tumor boundary delineation,showing great advantages in tumor diagnosis and treatment.展开更多
Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in hu...Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in humans remain unclear,including cell viability,distribution,migration,and fate.Conventional cell tracing methods cannot be used in the clinic.The use of superparamagnetic iron oxide nanoparticles as contrast agents allows for the observation of transplanted cells using magnetic resonance imaging.In 2016,the National Medical Products Administration of China approved a new superparamagnetic iron oxide nanoparticle,Ruicun,for use as a contrast agent in clinical trials.In the present study,an acute hemi-transection spinal cord injury model was established in beagle dogs.The injury was then treated by transplantation of Ruicun-labeled mesenchymal stromal cells.The results indicated that Ruicunlabeled mesenchymal stromal cells repaired damaged spinal cord fibers and partially restored neurological function in animals with acute spinal cord injury.T2*-weighted imaging revealed low signal areas on both sides of the injured spinal cord.The results of quantitative susceptibility mapping with ultrashort echo time sequences indicated that Ruicun-labeled mesenchymal stromal cells persisted stably within the injured spinal cord for over 4 weeks.These findings suggest that magnetic resonance imaging has the potential to effectively track the migration of Ruicun-labeled mesenchymal stromal cells and assess their ability to repair spinal cord injury.展开更多
Sulfamethoxazole(SMX)contamination in farmland disrupts soil micro-ecological functions,posing a risk to soil health and productivity.Sulfidated zero-valent iron(SZVI),a promising green material known for its good rea...Sulfamethoxazole(SMX)contamination in farmland disrupts soil micro-ecological functions,posing a risk to soil health and productivity.Sulfidated zero-valent iron(SZVI),a promising green material known for its good reactivity,had been used for soil remediation.However,existing studies often overlooked the effects of particle size and sulfur content on the long-term performance of SZVI and its impact on soil micro-ecological safety.This study employed polysulfide-modified nano,micro-nano,and micron-sized SZVI to investigate how particle size and sulfur content influenced the reactivity and durability,as well as the iron oxide forms and microbial community of soil during the SMX remediation.The results demonstrated that micro-nano sized SZVI(nm-SZVI)exhibited prolonged reactivity,achieving 83.12%-99.91%SMX removal over 30 days and maintaining higher levels of soil amorphous and reactive ferrous iron.Although sulfidation improved reactivity,excessive sulfur content reduced removal efficiency and accelerated the conversion to soil crystalline iron forms.Compared to nanoparticles,nm-SZVI fostered microbial diversity and balanced functional bacteria for electron transfer,organic matter utilization,and nutrient cycling.However,the elevated sulfur content in SZVI inhibited the stability of the microbial network.Finally,it was found that SMX underwent isoxazole reduction cleavage and oxidative removal pathways,reducing ecological toxicity.This study provided a new insight into the rational design of SZVI to achieve long-term pollutant removal and ensuring the health and stability of the microbial community by regulating particle size and sulfur content in soil remediation.展开更多
Iron oxide supported Au nanomaterials are one of the most studied catalysts for low-temperature CO oxidation.Catalytic performance not only critically depends on the size of the supported Au nanoparticles(NPs)but also...Iron oxide supported Au nanomaterials are one of the most studied catalysts for low-temperature CO oxidation.Catalytic performance not only critically depends on the size of the supported Au nanoparticles(NPs)but also strongly on the chemical nature of the iron oxide.In this study,Au NPs supported on iron oxide nanorods with different surface properties throughβ-FeOOH annealing,at varying temperatures,were synthesized,and applied in the CO oxidation.Detailed characterizations of the interactions between Au NPs and iron oxides were obtained by X-ray diffraction,transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy.The results indicate that the surface hydroxyl group on the Au/FeOOH catalyst,before calcination(Au/FeOOH-fresh),could facilitate the oxygen adsorption and dissociation on positively charged Au,thereby contributing to the low-temperature CO oxidation reactivity.After calcination at 200℃,under air exposure,the chemical state of the supported Au NP on varied iron oxides partly changed from metal cation to Au0,along with the disappearance of the surface OH species.Au/FeOOH with the highest Au0 content exhibits the highest activity in CO oxidation,among the as-synthesized catalysts.Furthermore,good durability in CO oxidation was achieved over the Au/FeOOH catalyst for 12 h without observable deactivation.In addition,the advanced identical-location TEM method was applied to the gas phase reaction to probe the structure evolution of the Au/iron oxide series of the catalysts and support structure.A Au NP size-dependent Ostwald ripening process mediated by the transport of Au(CO)x mobile species under certain reaction conditions is proposed,which offers a new insight into the validity of the structure-performance relationship.展开更多
Developing efficient water oxidation catalysts(WOCs)with earth‐abundant elements still remains a challenging task for artificial photosynthesis.Iron‐based WOC is a promising candidate because it is economically chea...Developing efficient water oxidation catalysts(WOCs)with earth‐abundant elements still remains a challenging task for artificial photosynthesis.Iron‐based WOC is a promising candidate because it is economically cheap,little toxic and environmentally friendly.In this study,we found that the catalytic water oxidation activity on amorphous iron‐based oxide/hydroxide(FeOx)can be decreased by an order of magnitude after the dehydration process at room temperature.Thermogravimetric analysis,XRD and Raman results indicated that the dehydration process of FeOx at room temperature causes the almost completely loss of water molecule with no bulk structural changes.Based on this finding,we prepared hydrated ultrasmall(ca.2.2 nm)FeOx nanoparticles of amorphous feature,which turns out to be extremely active as WOC with turnover frequency(TOF)up to 9.3 s^-1 in the photocatalytic Ru(bpy)3^2+‐Na2S2O8 system.Our findings suggest that future design of active iron‐based oxides as WOCs requires the consideration of their hydration status.展开更多
Arsenic(As)contamination in soil and water poses a serious threat to the ecosystem health and human beings,and is of widespread concern.The main As species found in soil and water are arsenite As(Ⅲ)and arsenate As(V)...Arsenic(As)contamination in soil and water poses a serious threat to the ecosystem health and human beings,and is of widespread concern.The main As species found in soil and water are arsenite As(Ⅲ)and arsenate As(V).Because As(Ⅲ)is more toxic and often more mobile than As(Ⅴ),many remediation strategies aim to oxidize As(Ⅲ)to As(Ⅴ).In the environment,the reduction of As(Ⅴ)under anaerobic conditions is mainly mediated by microorganisms,but the oxidation of As(Ⅲ)under aerobic conditions can be mediated primarily by chemical processes.This article first reviews the existing knowledge on chemical oxidation of As(Ⅲ)in the environment,with an emphasis on the roles of iron(Fe)and manganese(Mn)oxides.The application of Fe and Mn oxides for the remediation of As-contaminated soil and water is then summarized.The oxidation of As(Ⅲ)by oxygen is very slow in the absence of catalysts.Many Mn oxides,on the other hand,can efficiently oxidize As(Ⅲ).Although the oxidation of As(Ⅲ)by Fe(Ⅲ)is also slow,this process can be accelerated by light or Fe(Ⅱ).Iron and Mn oxides are widely used for the remediation of As-contaminated soil and water,with Fe oxides generally acting as absorbents while Mn oxides as oxidants.To better understand and regulate As transformation and transport in the environment,further study is needed on the mechanisms and influencing factors of As(Ⅲ)oxidation by Fe and Mn oxides,and the development of innovative methods and materials based on Fe and Mn oxides are desired.展开更多
The cerium iron complex oxides oxygen carrier was prepared by the co-precipitation method. The reactions between methane and lattice oxygen from the complex oxides were investigated in a fixed micro-reactor system. Th...The cerium iron complex oxides oxygen carrier was prepared by the co-precipitation method. The reactions between methane and lattice oxygen from the complex oxides were investigated in a fixed micro-reactor system. The reduced oxygen carder could be re-oxidized by air and its initial state could be restored. The characterizations of the oxygen carders were studied using XRD, O2-TPD, and H2-TPR. The results showed that the bulk lattice oxygen of CeO2-Fe2O3 was found to be suitable for the partial oxidation of methane to synthesis gas. There were two kinds of oxygen species on the oxygen carrier： the stronger oxygen species that was responsible for the complete oxidation of methane, and the weaker oxygen species （bulk lattice oxygen） that was responsible for the selective oxidation of methane to CO and H2 at a higher temperature. Then, the lost bulk lattice oxygen could be selectively supplemented by air re-oxidation at an appropriate reaction condition. CeFeO3 appeared on the oxygen carrier after 10 successive redox cycles, however, it was not bad for the selectivity of CO and H2.展开更多
Nanostructured iron oxyhydroxide（Fe OOH） thin films have been synthesized using an electrodeposition method on a nickel foam（NF） substrate and effect of air annealing temperature on the catalytic performance is st...Nanostructured iron oxyhydroxide（Fe OOH） thin films have been synthesized using an electrodeposition method on a nickel foam（NF） substrate and effect of air annealing temperature on the catalytic performance is studied. The as-deposited and annealed thin films were characterized by X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）, field emission scanning electron microscopy（FE-SEM） and linear sweep voltammetry（LSV） to determine their structural, morphological, compositional and electrochemical properties, respectively. The as-deposited nanostructured amorphous Fe OOH thin film is converted into a polycrystalline Fe;O;with hematite crystal structure at a high temperature. The Fe OOH thin film acts as an efficient electrocatalyst for the oxygen evolution reaction（OER） in an alkaline 1 M KOH electrolyte. The film annealed at 200 °C shows high catalytic activity with an onset overpotential of 240 m V with a smaller Tafel slope of 48 m V/dec. Additionally, it needs an overpotential of 290 mV to the drive the current density of 10 m A/cm;and shows good stability in the 1 M KOH electrolyte solution.展开更多
An iron（Ⅲ）-catalyzed selective oxidation of 5-HMF to 2,5-DFF in air at room temperature was developed.This approach gives 2,5-DFF with good selectivity and yields. Additionally, a two-step process was developed for...An iron（Ⅲ）-catalyzed selective oxidation of 5-HMF to 2,5-DFF in air at room temperature was developed.This approach gives 2,5-DFF with good selectivity and yields. Additionally, a two-step process was developed for the oxidation of 2,5-DFF to 2,5-FDCA at remarkably high substrate concentrations. This work demonstrates unequivocally the great potential of iron as a cheap and earth-abundant catalyst for the development of new protocols for the conversion of biomass to value-added chemicals.展开更多
Iron oxide nanoparticles（FeOx NPs, 5–30 nm size） prepared via laser ablation in liquid were supported onto Indium Tin Oxide conductive glass slides by magnetophoretic deposition（MD） technique. The resulting Fe O ...Iron oxide nanoparticles（FeOx NPs, 5–30 nm size） prepared via laser ablation in liquid were supported onto Indium Tin Oxide conductive glass slides by magnetophoretic deposition（MD） technique. The resulting Fe O x@ITO electrodes are characterized by a low amount of iron coverage of 16–50 nmol/cm^2,and show electrocatalytic activity towards water oxidation in neutral phosphate buffer pH 7 with 0.58 V overpotential and quantitative Faradaic efficiency towards oxygen production. XPS analysis on the oxygen region of the FeOx films reveals a substantial hydration of the surface after catalysis, recognized as a crucial step to access reactivity.展开更多
Oxidation of alkybenzenes PhCH_2R(R=H, CH_3, C_2H_5 and n-C_3H_7) under 1 atm. of O_2 or air catalyzed by iron(Ⅱ, Ⅲ)-2,2'-bipyridine and 1,10-phenanthroline complexes, affords the aryl-substituted ketones and al...Oxidation of alkybenzenes PhCH_2R(R=H, CH_3, C_2H_5 and n-C_3H_7) under 1 atm. of O_2 or air catalyzed by iron(Ⅱ, Ⅲ)-2,2'-bipyridine and 1,10-phenanthroline complexes, affords the aryl-substituted ketones and alcohols with the conversion of 15.00％～34.58％ containing of 97.60％～99.80％ ketones and alcohols. The turnover numbers of these catalysts are over 3500 mol-cat. ^(-1)for 3.5 h.展开更多
Extremely small-sized iron oxide nanoparticles(IONPs) are of great interest in magnetic resonance imaging(MRI) due to their biosafety as an alternative to clinical gadolinium(Ⅲ) complexes-based contrast agents.Especi...Extremely small-sized iron oxide nanoparticles(IONPs) are of great interest in magnetic resonance imaging(MRI) due to their biosafety as an alternative to clinical gadolinium(Ⅲ) complexes-based contrast agents.Especially when the particle size is less than 10 nm,it has strong diffusion ability and deep penetration distance in tumor tissue.Substitution doping can significantly enhance the T_(1)contrast effect of nanoparticles by regulating the surface exposed atoms.However,the nucleation and growth processes of multi-component synthesis systems are complex and difficult to be accurately controlled,leading to great challenges in the synthesis of ultra-small-sized nanoparticles with different components and sizes.Here,extremely smallsized superparamagnetic gadolinium-doped iron oxide nanoparticles(GdIONPs,Gd_(x)Fe_(3-x)O_(4) NPs) with adjustable doping amount and controllable size in the range of 3.5-7.5 nm were synthesized by thermal decomposition.Then,as-synthesized GdIONPs were surface modified with a highly water-soluble and biocompatible carboxyl-polyethylene glycol-phosphoric acid ligand with high binding affinity.Gd_(0.65)Fe_(2.35)O_(4) NPs exhibited very high r_(1) relaxivity of 10.6 mmol^(-1)·L·s^(-1) in terms of all metal concentrations and 49.0 mmol^(-1)·L·s^(-1) in terms of gadolinium alone,respectively,3 and 14 times higher than clinical T_(1) contrast agents(Gd-DTPA).GdIONPs can continuously obtain high resolution images of blood vessels,and can be used as an efficient and multifunctional contrast agent for MR T_(1)imaging.This stable and efficient doping strategy provides an easy and effective method to individually optimize the magnetic properties of complex oxides and their relaxation effects for a variety of biomedical applications.展开更多
Soil flooding and drainage can cause the reduction and oxidation of iron(Fe),as well as the immobilization and mobilization of cadmium(Cd).However,the impact of Fe(Ⅱ)oxidation following microbial Fe(Ⅲ)reduction on C...Soil flooding and drainage can cause the reduction and oxidation of iron(Fe),as well as the immobilization and mobilization of cadmium(Cd).However,the impact of Fe(Ⅱ)oxidation following microbial Fe(Ⅲ)reduction on Cd mobility remains unclear.In this study,we examined the behavior of Cd during microbial reduction of Fe(Ⅲ)oxides and subsequent chemical re-oxidation of Fe(Ⅱ)using batch reactor systems.The bacterium Shewanella oneidensis MR-1was incubated with ferrihydrite,lepidocrocite,goethite,or hematite anaerobically and then aerobically in media containing 212μg L^(-1)Cd,with or without pH buffering(initial pH=7.0).Compared to the control systems without MR-1,microbial Fe(Ⅲ)reduction significantly promoted the immobilization of dissolved Cd,as well as the conversion of dissolved and adsorbed Cd to strongly bound Cd that could not be extracted by.0.4 mol L^(-1)HCl.The mechanisms of Cd immobilization were different during the microbial reduction of different Fe(Ⅲ)oxides.The buffering of system pH affected the phase of Fe oxides formed at the reduction and oxidation stages in the systems containing MR-1 and ferrihydrite or lepidocrocite.Nevertheless,in all the systems containing MR-1 and Fe oxides,irrespective of pH buffering,the concentration of dissolved Cd dropped to<1μg L^(-1)after 35 d of anaerobic incubation and remained<4μg L^(-1)after subsequent 72 h of aerobic incubation.This suggests that Fe(Ⅱ)oxidation after microbial Fe(Ⅲ)reduction(generating 0.025-0.22 g L^(-1)Fe(Ⅱ))does not result in Cd release.展开更多
Secondary iron-sulfate minerals such as jarosite,which are easily formed in acid mine drainage,play an important role in controlling metal mobility.In this work,the typical iron-oxidizing bacterium Acidithiobacillus f...Secondary iron-sulfate minerals such as jarosite,which are easily formed in acid mine drainage,play an important role in controlling metal mobility.In this work,the typical iron-oxidizing bacterium Acidithiobacillus ferrooxidans ATCC 23270 was selected to synthesize jarosite in the presence of antimony ions,during which the solution behavior,synthetic product composition,and bacterial metabolism were studied.The results show that in the presence of Sb(V),Fe^(2+)was rapidly oxidized to Fe^(3+)by A.ferrooxidans and Sb(V)had no obvious effect on the biooxidation of Fe^(2+)under the current experimental conditions.The presence of Sb(Ⅲ)inhibited bacterial growth and Fe^(2+)oxidation.For the group with Sb(Ⅲ),products with amorphous phaseswere formed 72 hr later,whichwere mainly ferrous sulfate and pentavalent antimony oxide,and the amorphous precursor was finally transformed into a more stable crystal phase.For the group with Sb(V),the morphology and structure of jarosite were changed in comparison with those without Sb.The biomineralization process was accompanied by the removal of 94%Sb(V)to form jarosite containing the Fe-Sb-O complex.Comparative transcriptome analysis shows differential effects of Sb(Ⅲ)and Sb(V)on bacterial metabolism.The expression levels of functional genes related to cell components were much more downregulated for the group with Sb(Ⅲ)butmuch more regulated for that with Sb(V).Notably,cytochrome c and nitrogen fixation-relevant genes for the A.f_Fe^(2+)_Sb(Ⅲ)group were enhanced significantly,indicating their role in Sb(Ⅲ)resistance.This study is of great value for the development of antimony pollution control and remediation technology.展开更多
文摘The surface oxidation patterns of iron or low-carbon steels are critical to their life when serving in typical damp environments. An accurate determination of the oxidation pattern entails tracking the iron atoms oxidized at the iron/steel-moisture interface. Using a quantum chemistry-based force field that is capable of simulating chemical reactions, this paper studies the process of iron oxidation under a typical moist condition. The oxidation of iron surface was found to be highly thermodynamic and dependent on the availability of reactants. A triplex structure was formed at the end of a three-stage oxidation process to reduce the overall oxidation speed. The results from this study shed light on the atomistic mechanism of iron oxidation; therefore can be used to guide the protection of general ferrous-based iron/steel structures.
基金supported by the National Natural Science Foundation of China(Nos.42207309 and 22306087)the Natural Science Foundation of Hunan Province(Nos.2022JJ40369 and 2023JJ40547)the Program for Education Department of Hunan Province,China(No.21B0405).
文摘The abiotic oxidation of divalentmanganese(Mn(Ⅱ))and the formation of Mn oxides are important geochemical processes,which control the mobility and availability of Mn as well as element cycling and pollutant behavior in soils.It was found that iron(oxyhydr)oxides can catalyze Mn(Ⅱ)oxidation,but the effects of the coexisting dissolved organic matter(DOM)molecules on the catalysis of different iron(oxyhydr)oxides for Mn(Ⅱ)oxidation are poorly understood.Herein,we investigated Mn(Ⅱ)oxidation under the impacts of the interactions between iron(oxyhydr)oxides(i.e.,ferrihydrite,goethite and hematite)and DOM molecules.Simultaneously,we elucidated the variations of DOM composition and properties.Our results indicated that the catalysis of iron(oxyhydr)oxides for Mn(Ⅱ)oxidation was significantly inhibited by DOM.Moreover,DOM had less inhibiting effect on the catalysis of ferrihydrite for Mn(Ⅱ)oxidation and the formation of Mn oxides(e.g.,hausmannite and buserite)relative to goethite and hematite,whichwas partially because of the higher electron transfer capacities of ferrihydrite.Meanwhile,DOM molecules with high nominal oxidation state of carbon(NOSC),molecular weight,unsaturation and aromaticity were selectively adsorbed and oxidized by Mn oxides,including the oxygenated phenols and polyphenols.The newly formed molecules mainly belonged to phenols depleted of oxygen and aliphatics.Furthermore,NOSC was a key molecular characteristic for controlling DOM composition during DOM adsorption and oxidation by Mn oxides when iron minerals were present.Overall,our research contributes to understanding Mn(Ⅱ)oxidation mechanisms under heterogeneous systems and behaviors of DOM molecules in the environment.
基金supported by the Shenyang Municipal Science and Technology Project,China(23-409-2-03)the Liaoning Provincial Department of Science and Technology Project,China(Z20230183)the Liaoning Provincial Applied Basic Research Program,China(2022JH2/101300173).
文摘Both soil organic carbon (SOC) and iron (Fe) oxide content, among other factors, drive the formation and stability of soil aggregates.However, the mechanism of these drivers in greenhouse soil fertilized with organic fertilizer is not well understood.In a 3-year field experiment, we aimed to investigate the factors which drive the stability of soil aggregates in greenhouse soil.To explore the impact of organic fertilizer on soil aggregates, we established four treatments:no fertilization (CK);inorganic fertilizer (CF);organic fertilizer (OF);and combined application of inorganic and organic fertilizers(COF).The application of organic fertilizer significantly enhanced the stability of aggregates, that is it enhanced the mean weight diameter, geometric mean diameter and aggregate content (%) of>0.25 mm aggregate fractions.OF and COF treatments increased the concentration of SOC, especially the aliphatic-C, aromatic-C and polysaccharide-C components of SOC, particularly in>0.25 mm aggregates.Organic fertilizer application significantly increased the content of free Fe(Fed), reactive Fe (Feo), and non-crystalline Fe in both bulk soil and aggregates.Furthermore, non-crystalline Fe showed a positive correlation with SOC content in both bulk soil and aggregates.Both non-crystalline Fe and SOC were significantly positively correlated with>2 mm mean weight diameter.Overall, we believe that the increase of SOC, aromatic-C, and non-crystal ine Fe concentrations in soil after the application of organic fertilizer is the reason for improving soil aggregate stability.
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 efficiency and mechanism of hydrous iron oxide(HFO)and HFO/calcite mixture to inactivate the phosphorus in the overlying water(OW)/sediment system under the feed adding condition were explored,and the effect of HFO and HFO/calcite mixture addition on the diversity,composition and function of bacterial communities in the sediment was examined.HFO and HFO/calcite mixture direct addition can effectively lower the concentration of soluble reactive phosphorus(RSP)and diffusion gradient in thin film-unstable phosphorus(PD GT)in OW and inactivate the P DGTin the upper sediment.The elimination efficiencies of RSP by the direct HFO and HFO/calcite mixture addition were 48.9%-97.0%and 42.4%-95.4%,respectively.The alteration in the addition mode from the one-time to multiple direct addition was beneficial to the immobilization of RSP and PD GTin OW and P DGTin the upper sediment by HFO and HFO/calcite mixture under the feed input condition in the long run.Permeable fabric wrapping reduced the inactivation efficiency of RSP in OW by HFO and HFO/calcite mixture,but it made the recycling of these materials possible.Most of P immobilized by HFO and HFO/calcite mixture was relatively or very stable.After the HFO and HFO/calcite mixture addition,the composition of bacterial communities in the surface sediment changed.However,the bacterial communities in the amended sediments still can perform good ecological function.Our findings suggest that HFO and HFO/calcite mixture are promising phosphorus-immobilization materials for the inactivation of RSP and PD GTin OW and PD GTin the upper sediment under the feed inputting condition.
基金Technology Program of Jiaying University,No.2024KJZ01Open Funding of Guangdong Provincial Key Laboratory of Conservation and Precision Utilization of Characteristic Agricultural Resources in Mountainous Areas,No.2023JYKF08National Natural Science Foundation of China,No.42277442。
文摘The conversion of subtropical red soils into farmland involves complex transformations of iron oxides.Investigating iron mineralogy can enhance understanding of magnetic minerals in relation to soil formation on farmland in subtropical regions.In this study,we investigated the properties of iron oxide and its environmental implications in the farmland of Meizhou city,Guangdong province.The results showed that farmland soils had higher magnetism than the red soils developed from the same metamorphic rock.The red soils displayed significantly higher concentrations of goethite and hematite than the farmland soils.The dominant factor influencing the magnetic changes in farmland and red soils was the concentration of fine-grained ferromagnetic minerals.Red soil magnetism is an indicator of soil weathering intensity,whereas farmland soil magnetism is closely related to human cultivation activities.In contrast to the red soils,the farmland soils lacked the pronounced transformation of ferromagnetic minerals into hematite and goethite.A vigorous oxidation process catalyzes the transformation of strong magnetic minerals into significant amounts of hematite and goethite,which promotes the reduced magnetism of red soils.The conversion of red soils into farmland soils initially increased the accumulation of ferromagnetic materials due to cultivation processes.However,long-term cultivation led to the gradual loss of fine-grained ferromagnetic minerals,while goethite and lepidocrocite became the dominant magnetic mineral types.
基金supported by the National Key R&D Program of China(No.2023YFC3708302)the National Natural Science Foundation of China(Nos.22188102 and 22306041)+1 种基金the Chinese Academy of Sciences Project for Young Scientists in Basic Research(No.YSBR-086)China Postdoctoral Science Foundation(No.2023M733679).
文摘Magnetic iron oxide nanoparticles(Fe_(x)O_(y) NPs,mainly Fe3O4 andγ-Fe2O_(3))are nanomaterials ubiquitously present in aquatic,terrestrial,and atmospheric environments,with a high prevalence and complex sources.Over the past decade,numerous reports have emerged on the presence of exogenous particles in human body,facilitated by the rapid development of separation and detection methods.The health risk associated with magnetic Fe_(x)O_(y) NP have garnered escalating attention due to their presence in human blood and brain tissues,especially for their potential association with neurodegenerative diseases like Alzheimer’s disease.In this paper,we provide a comprehensive overview of sources,analysis methods,environmental impacts,and health risks of magnetic Fe_(x)O_(y) NP.Currently,most researches are primarily based on engineered Fe_(x)O_(y) NP,while reports aboutmagnetic Fe_(x)O_(y) NP existing in real-world environments are still limited,especially for their occurrence levels in various environmental matrices,environmental transformation behavior,and biotoxic effects.Our study reviews this emerging pollutant,providing insights to address current research deficiencies and chart the course for future studies.
基金supported by the funding from National Natural Science Foundation of China(Nos.32025021,12374390,31971292,82072032,82202274)Ningbo 3315 Innovative Teams Program(No.2019A-14-C)+6 种基金The member of Youth Innovation Promotion Association Foundation of CAS(No.2023310)Key Scientific and Technological Special Project of Ningbo City(Nos.2023Z209,2020Z189)National Key R&D Program of China(No.2019YFA0405603)Provincial Natural Science Foundation of Zhejiang(Nos.LQ23H180007,LQ23H180003)Zhejiang Province Science and Technology Plan of Traditional Chinese Medicine(No.2021KY085)Zhejiang Provincial Traditional Chinese Medicine Foundation(No.2021ZB04)the Major Medical and Health Science and Technology Project of Zhejiang Province(No.WKJ-ZJ-2002)。
文摘Early diagnosis and accurate boundary delineation are the key steps of tumor precision medicine.Circulating tumor cells(CTCs)detection of liquid biopsy can provide abundant information for early diagnosis of cancer.High detection specificity and good enrichment features are two key factors for CTCs accurate identification in peripheral blood sample.For this purpose,iron oxide(IO)-based surface-enhanced Raman scattering(SERS)bioprobes with good biocompatibility,high detection sensitivity,remarkable detection specificity,and good enrichment efficiency,were developed for detecting different types of CTCs.Magnetic SERS bioprobes combined with programmed death ligand-1(PD-L1)antibody are regarded as an effective way to boost the targeting ability and detection specificity,benefiting for accurately capturing and identifying rare CTCs.Four types of CTCs with different PD-L1 expression were accurately distinguished among white blood cells via high-resolution SERS mapping images and stable Raman signals.Subsequently,CTCs blood samples obtained from the triple negative breast cancer patients were also successfully recognized compared to that of health people,indicating IO@AR@PDA-a PD-L1 SERS bioprobe possessed great potential for CTCs detection in liquid biopsy.Additionally,IO-based bioprobe exhibited excellent dual-modal imaging abilities of high-resolution SERS imaging mode and microimaging magnetic resonance imaging mode.These two highly complementary imaging modes endowed IO-based bioprobes unrivalled capacity in tumor boundary differentiation,supporting tumor accurate resection and precise surgery.To our best knowledge,this is the first time that biocompatible IO-based SERS bioprobes without noble metal element were reported not only for CTCs accurate detection,but also for precise tumor boundary delineation,showing great advantages in tumor diagnosis and treatment.
基金supported by the National Key R&D Program of China,Nos.2017YFA0104302(to NG and XM)and 2017YFA0104304(to BW and ZZ)
文摘Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in humans remain unclear,including cell viability,distribution,migration,and fate.Conventional cell tracing methods cannot be used in the clinic.The use of superparamagnetic iron oxide nanoparticles as contrast agents allows for the observation of transplanted cells using magnetic resonance imaging.In 2016,the National Medical Products Administration of China approved a new superparamagnetic iron oxide nanoparticle,Ruicun,for use as a contrast agent in clinical trials.In the present study,an acute hemi-transection spinal cord injury model was established in beagle dogs.The injury was then treated by transplantation of Ruicun-labeled mesenchymal stromal cells.The results indicated that Ruicunlabeled mesenchymal stromal cells repaired damaged spinal cord fibers and partially restored neurological function in animals with acute spinal cord injury.T2*-weighted imaging revealed low signal areas on both sides of the injured spinal cord.The results of quantitative susceptibility mapping with ultrashort echo time sequences indicated that Ruicun-labeled mesenchymal stromal cells persisted stably within the injured spinal cord for over 4 weeks.These findings suggest that magnetic resonance imaging has the potential to effectively track the migration of Ruicun-labeled mesenchymal stromal cells and assess their ability to repair spinal cord injury.
基金supported by the National Natural Science Foundation of China(No.22478226)Shandong Provincial Natural Science Foundation(Nos.ZR2023JQ022 and ZR2024QE165)+1 种基金the Postdoctoral Fellowship Program of CPSF(No.GZC20240917)Taishan Scholars Project of Shandong Province(No.tstp20230604)。
文摘Sulfamethoxazole(SMX)contamination in farmland disrupts soil micro-ecological functions,posing a risk to soil health and productivity.Sulfidated zero-valent iron(SZVI),a promising green material known for its good reactivity,had been used for soil remediation.However,existing studies often overlooked the effects of particle size and sulfur content on the long-term performance of SZVI and its impact on soil micro-ecological safety.This study employed polysulfide-modified nano,micro-nano,and micron-sized SZVI to investigate how particle size and sulfur content influenced the reactivity and durability,as well as the iron oxide forms and microbial community of soil during the SMX remediation.The results demonstrated that micro-nano sized SZVI(nm-SZVI)exhibited prolonged reactivity,achieving 83.12%-99.91%SMX removal over 30 days and maintaining higher levels of soil amorphous and reactive ferrous iron.Although sulfidation improved reactivity,excessive sulfur content reduced removal efficiency and accelerated the conversion to soil crystalline iron forms.Compared to nanoparticles,nm-SZVI fostered microbial diversity and balanced functional bacteria for electron transfer,organic matter utilization,and nutrient cycling.However,the elevated sulfur content in SZVI inhibited the stability of the microbial network.Finally,it was found that SMX underwent isoxazole reduction cleavage and oxidative removal pathways,reducing ecological toxicity.This study provided a new insight into the rational design of SZVI to achieve long-term pollutant removal and ensuring the health and stability of the microbial community by regulating particle size and sulfur content in soil remediation.
基金supported by the National Natural Science Foundation of China(21773269,21761132025,91545119,21703262)the Youth Innovation Promotion Association CAS(2015152)+1 种基金the Joint Foundation of Liaoning Province Natural Science FoundationShenyang National Laboratory for Materials Science(20180510047)~~
文摘Iron oxide supported Au nanomaterials are one of the most studied catalysts for low-temperature CO oxidation.Catalytic performance not only critically depends on the size of the supported Au nanoparticles(NPs)but also strongly on the chemical nature of the iron oxide.In this study,Au NPs supported on iron oxide nanorods with different surface properties throughβ-FeOOH annealing,at varying temperatures,were synthesized,and applied in the CO oxidation.Detailed characterizations of the interactions between Au NPs and iron oxides were obtained by X-ray diffraction,transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy.The results indicate that the surface hydroxyl group on the Au/FeOOH catalyst,before calcination(Au/FeOOH-fresh),could facilitate the oxygen adsorption and dissociation on positively charged Au,thereby contributing to the low-temperature CO oxidation reactivity.After calcination at 200℃,under air exposure,the chemical state of the supported Au NP on varied iron oxides partly changed from metal cation to Au0,along with the disappearance of the surface OH species.Au/FeOOH with the highest Au0 content exhibits the highest activity in CO oxidation,among the as-synthesized catalysts.Furthermore,good durability in CO oxidation was achieved over the Au/FeOOH catalyst for 12 h without observable deactivation.In addition,the advanced identical-location TEM method was applied to the gas phase reaction to probe the structure evolution of the Au/iron oxide series of the catalysts and support structure.A Au NP size-dependent Ostwald ripening process mediated by the transport of Au(CO)x mobile species under certain reaction conditions is proposed,which offers a new insight into the validity of the structure-performance relationship.
基金supported by the Basic Research Program of China(973 Program,2014CB239403)National Natural Science Foundation of China(21522306,21633009)Key Research Program of Frontier Sciences,CAS(QYZDY-SSW-JSC023)
文摘Developing efficient water oxidation catalysts(WOCs)with earth‐abundant elements still remains a challenging task for artificial photosynthesis.Iron‐based WOC is a promising candidate because it is economically cheap,little toxic and environmentally friendly.In this study,we found that the catalytic water oxidation activity on amorphous iron‐based oxide/hydroxide(FeOx)can be decreased by an order of magnitude after the dehydration process at room temperature.Thermogravimetric analysis,XRD and Raman results indicated that the dehydration process of FeOx at room temperature causes the almost completely loss of water molecule with no bulk structural changes.Based on this finding,we prepared hydrated ultrasmall(ca.2.2 nm)FeOx nanoparticles of amorphous feature,which turns out to be extremely active as WOC with turnover frequency(TOF)up to 9.3 s^-1 in the photocatalytic Ru(bpy)3^2+‐Na2S2O8 system.Our findings suggest that future design of active iron‐based oxides as WOCs requires the consideration of their hydration status.
基金supported by the National Natural Science Foundation of China(Nos.41977273 and U21A20291)the National Key Research and Development Program of China(No.2018YFC1800702)+1 种基金the Major Research Plan of the Shandong Science Foundation,China(No.ZR2020ZD19)funding from the Special Fund for Basic Scientific Research Business of Central Public Research Institutes,China(No.K-JBYWF-2019-T04).
文摘Arsenic(As)contamination in soil and water poses a serious threat to the ecosystem health and human beings,and is of widespread concern.The main As species found in soil and water are arsenite As(Ⅲ)and arsenate As(V).Because As(Ⅲ)is more toxic and often more mobile than As(Ⅴ),many remediation strategies aim to oxidize As(Ⅲ)to As(Ⅴ).In the environment,the reduction of As(Ⅴ)under anaerobic conditions is mainly mediated by microorganisms,but the oxidation of As(Ⅲ)under aerobic conditions can be mediated primarily by chemical processes.This article first reviews the existing knowledge on chemical oxidation of As(Ⅲ)in the environment,with an emphasis on the roles of iron(Fe)and manganese(Mn)oxides.The application of Fe and Mn oxides for the remediation of As-contaminated soil and water is then summarized.The oxidation of As(Ⅲ)by oxygen is very slow in the absence of catalysts.Many Mn oxides,on the other hand,can efficiently oxidize As(Ⅲ).Although the oxidation of As(Ⅲ)by Fe(Ⅲ)is also slow,this process can be accelerated by light or Fe(Ⅱ).Iron and Mn oxides are widely used for the remediation of As-contaminated soil and water,with Fe oxides generally acting as absorbents while Mn oxides as oxidants.To better understand and regulate As transformation and transport in the environment,further study is needed on the mechanisms and influencing factors of As(Ⅲ)oxidation by Fe and Mn oxides,and the development of innovative methods and materials based on Fe and Mn oxides are desired.
基金the National Natural Science Foundation of China (50574046)National Natural Science Foundation of Major Research Projects (90610035)+1 种基金Natural Science Foundation of Yunnan Province (2004E0058Q)High School Doctoral Subject Special Science and Research Foundation of Ministry of Education (20040674005)
文摘The cerium iron complex oxides oxygen carrier was prepared by the co-precipitation method. The reactions between methane and lattice oxygen from the complex oxides were investigated in a fixed micro-reactor system. The reduced oxygen carder could be re-oxidized by air and its initial state could be restored. The characterizations of the oxygen carders were studied using XRD, O2-TPD, and H2-TPR. The results showed that the bulk lattice oxygen of CeO2-Fe2O3 was found to be suitable for the partial oxidation of methane to synthesis gas. There were two kinds of oxygen species on the oxygen carrier： the stronger oxygen species that was responsible for the complete oxidation of methane, and the weaker oxygen species （bulk lattice oxygen） that was responsible for the selective oxidation of methane to CO and H2 at a higher temperature. Then, the lost bulk lattice oxygen could be selectively supplemented by air re-oxidation at an appropriate reaction condition. CeFeO3 appeared on the oxygen carrier after 10 successive redox cycles, however, it was not bad for the selectivity of CO and H2.
基金supported by the Human Resources Development program(no.20124010203180) of the Korea Institute of Energy Technology Evaluation and Planning(KETEP)Grant funded by the Korea government Ministry of Trade,Industry and Energysupported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science,ICT and Future Planning(NRF-2015R1A2A2A01006856)
文摘Nanostructured iron oxyhydroxide（Fe OOH） thin films have been synthesized using an electrodeposition method on a nickel foam（NF） substrate and effect of air annealing temperature on the catalytic performance is studied. The as-deposited and annealed thin films were characterized by X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）, field emission scanning electron microscopy（FE-SEM） and linear sweep voltammetry（LSV） to determine their structural, morphological, compositional and electrochemical properties, respectively. The as-deposited nanostructured amorphous Fe OOH thin film is converted into a polycrystalline Fe;O;with hematite crystal structure at a high temperature. The Fe OOH thin film acts as an efficient electrocatalyst for the oxygen evolution reaction（OER） in an alkaline 1 M KOH electrolyte. The film annealed at 200 °C shows high catalytic activity with an onset overpotential of 240 m V with a smaller Tafel slope of 48 m V/dec. Additionally, it needs an overpotential of 290 mV to the drive the current density of 10 m A/cm;and shows good stability in the 1 M KOH electrolyte solution.
基金the National Basic Research Program of China (Nos. 2013CB228103, 2012CB215306)NNSFC (Nos. 21472033, 21325208, 21172209)+3 种基金FRFCU (No. WK2060190025)SRFDP (No. 20123402130008)CAS (No. KJCX2-EW-J02)Fok Ying Tung Education Foundation for the financial support
文摘An iron（Ⅲ）-catalyzed selective oxidation of 5-HMF to 2,5-DFF in air at room temperature was developed.This approach gives 2,5-DFF with good selectivity and yields. Additionally, a two-step process was developed for the oxidation of 2,5-DFF to 2,5-FDCA at remarkably high substrate concentrations. This work demonstrates unequivocally the great potential of iron as a cheap and earth-abundant catalyst for the development of new protocols for the conversion of biomass to value-added chemicals.
基金supported by the Italian Ministero dell’Università e della Ricerca (MIUR), (FIRB RBAP11C58Y, "Nano Solar" and PRIN 2010 "Hi-Phuture")COST action CM1205 "CARISMA: CAtalytic Rout Ines for Small Molecule Activation"
文摘Iron oxide nanoparticles（FeOx NPs, 5–30 nm size） prepared via laser ablation in liquid were supported onto Indium Tin Oxide conductive glass slides by magnetophoretic deposition（MD） technique. The resulting Fe O x@ITO electrodes are characterized by a low amount of iron coverage of 16–50 nmol/cm^2,and show electrocatalytic activity towards water oxidation in neutral phosphate buffer pH 7 with 0.58 V overpotential and quantitative Faradaic efficiency towards oxygen production. XPS analysis on the oxygen region of the FeOx films reveals a substantial hydration of the surface after catalysis, recognized as a crucial step to access reactivity.
文摘Oxidation of alkybenzenes PhCH_2R(R=H, CH_3, C_2H_5 and n-C_3H_7) under 1 atm. of O_2 or air catalyzed by iron(Ⅱ, Ⅲ)-2,2'-bipyridine and 1,10-phenanthroline complexes, affords the aryl-substituted ketones and alcohols with the conversion of 15.00％～34.58％ containing of 97.60％～99.80％ ketones and alcohols. The turnover numbers of these catalysts are over 3500 mol-cat. ^(-1)for 3.5 h.
基金financially supported by the Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Five-Year Plan (No.CIT&TCD201804025)Beijing Municipal Education Commission (No.KM201910011009)the Graduate Student Scientific Research Ability Promotion of BTBU。
文摘Extremely small-sized iron oxide nanoparticles(IONPs) are of great interest in magnetic resonance imaging(MRI) due to their biosafety as an alternative to clinical gadolinium(Ⅲ) complexes-based contrast agents.Especially when the particle size is less than 10 nm,it has strong diffusion ability and deep penetration distance in tumor tissue.Substitution doping can significantly enhance the T_(1)contrast effect of nanoparticles by regulating the surface exposed atoms.However,the nucleation and growth processes of multi-component synthesis systems are complex and difficult to be accurately controlled,leading to great challenges in the synthesis of ultra-small-sized nanoparticles with different components and sizes.Here,extremely smallsized superparamagnetic gadolinium-doped iron oxide nanoparticles(GdIONPs,Gd_(x)Fe_(3-x)O_(4) NPs) with adjustable doping amount and controllable size in the range of 3.5-7.5 nm were synthesized by thermal decomposition.Then,as-synthesized GdIONPs were surface modified with a highly water-soluble and biocompatible carboxyl-polyethylene glycol-phosphoric acid ligand with high binding affinity.Gd_(0.65)Fe_(2.35)O_(4) NPs exhibited very high r_(1) relaxivity of 10.6 mmol^(-1)·L·s^(-1) in terms of all metal concentrations and 49.0 mmol^(-1)·L·s^(-1) in terms of gadolinium alone,respectively,3 and 14 times higher than clinical T_(1) contrast agents(Gd-DTPA).GdIONPs can continuously obtain high resolution images of blood vessels,and can be used as an efficient and multifunctional contrast agent for MR T_(1)imaging.This stable and efficient doping strategy provides an easy and effective method to individually optimize the magnetic properties of complex oxides and their relaxation effects for a variety of biomedical applications.
基金supported by the National Natural Science Foundation of China(Nos.41977273 and U21A20291)the Major Research Plan of the Shandong Science Foundation,China(No.ZR2020ZD19)。
文摘Soil flooding and drainage can cause the reduction and oxidation of iron(Fe),as well as the immobilization and mobilization of cadmium(Cd).However,the impact of Fe(Ⅱ)oxidation following microbial Fe(Ⅲ)reduction on Cd mobility remains unclear.In this study,we examined the behavior of Cd during microbial reduction of Fe(Ⅲ)oxides and subsequent chemical re-oxidation of Fe(Ⅱ)using batch reactor systems.The bacterium Shewanella oneidensis MR-1was incubated with ferrihydrite,lepidocrocite,goethite,or hematite anaerobically and then aerobically in media containing 212μg L^(-1)Cd,with or without pH buffering(initial pH=7.0).Compared to the control systems without MR-1,microbial Fe(Ⅲ)reduction significantly promoted the immobilization of dissolved Cd,as well as the conversion of dissolved and adsorbed Cd to strongly bound Cd that could not be extracted by.0.4 mol L^(-1)HCl.The mechanisms of Cd immobilization were different during the microbial reduction of different Fe(Ⅲ)oxides.The buffering of system pH affected the phase of Fe oxides formed at the reduction and oxidation stages in the systems containing MR-1 and ferrihydrite or lepidocrocite.Nevertheless,in all the systems containing MR-1 and Fe oxides,irrespective of pH buffering,the concentration of dissolved Cd dropped to<1μg L^(-1)after 35 d of anaerobic incubation and remained<4μg L^(-1)after subsequent 72 h of aerobic incubation.This suggests that Fe(Ⅱ)oxidation after microbial Fe(Ⅲ)reduction(generating 0.025-0.22 g L^(-1)Fe(Ⅱ))does not result in Cd release.
基金supported by the National Natural Science Foundation of China(Nos.41830318 and 51861135305).
文摘Secondary iron-sulfate minerals such as jarosite,which are easily formed in acid mine drainage,play an important role in controlling metal mobility.In this work,the typical iron-oxidizing bacterium Acidithiobacillus ferrooxidans ATCC 23270 was selected to synthesize jarosite in the presence of antimony ions,during which the solution behavior,synthetic product composition,and bacterial metabolism were studied.The results show that in the presence of Sb(V),Fe^(2+)was rapidly oxidized to Fe^(3+)by A.ferrooxidans and Sb(V)had no obvious effect on the biooxidation of Fe^(2+)under the current experimental conditions.The presence of Sb(Ⅲ)inhibited bacterial growth and Fe^(2+)oxidation.For the group with Sb(Ⅲ),products with amorphous phaseswere formed 72 hr later,whichwere mainly ferrous sulfate and pentavalent antimony oxide,and the amorphous precursor was finally transformed into a more stable crystal phase.For the group with Sb(V),the morphology and structure of jarosite were changed in comparison with those without Sb.The biomineralization process was accompanied by the removal of 94%Sb(V)to form jarosite containing the Fe-Sb-O complex.Comparative transcriptome analysis shows differential effects of Sb(Ⅲ)and Sb(V)on bacterial metabolism.The expression levels of functional genes related to cell components were much more downregulated for the group with Sb(Ⅲ)butmuch more regulated for that with Sb(V).Notably,cytochrome c and nitrogen fixation-relevant genes for the A.f_Fe^(2+)_Sb(Ⅲ)group were enhanced significantly,indicating their role in Sb(Ⅲ)resistance.This study is of great value for the development of antimony pollution control and remediation technology.
