Fe Source Research Articles

Trace Elements in Soy-Based Beverages: A Comprehensive Study of Total Content and In Vitro Bioaccessibility.

Soy-based beverages are one of the most consumed plant-based beverages, which have been used as a substitute for dairy products. Soy is a source of several nutrients (vitamins, minerals, and phenolic compounds, etc.) and its consumption is usually associated with several benefits, such as the prevention of cardiovascular diseases, cancer, and osteoporosis. However, non-essential trace elements can be found in these beverages. Thus, a comprehensive study concerning trace elements Al, As, Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Pb, Sb, Se, Sn, Sr, and Zn in soy-based beverages was proposed. In vitro digestion allowed to simulate the gastrointestinal juice (bioaccessibility) and the Caco-2 cells culture model was applied for the bioavailability assay. Trace elements measures were performed by inductively coupled plasma optical emission spectrometry (ICP OES). Multivariate analysis classified soy-based beverages according to their soy source (isolate protein, hydrosoluble extract, and beans); Al, Cu, Fe, Mn, Sr, Se, and Zn bioaccessible fractions corresponded to approximately 40%-80% of their total content, and soy-based beverages were found to be a good Fe, Se, and Zn source. However, our results showed risk exposure assessment from daily consumption of one glass of soy-based beverage can contribute to 3.5% and 0.9% of Al Provisional Tolerable Weekly Intake (PTWI) for children and adults, respectively.

Performance of TES X-Ray Microcalorimeters Designed for 14.4-keV Solar Axion Search

A ^{57}Fe nucleus in the solar core could emit a 14.4-keV monochromatic axion through the M1 transition if a hypothetical elementary particle, axion, exists to solve the strong CP problem. Transition edge sensor (TES) X-ray microcalorimeters can detect such axions very efficiently if they are again converted into photons by a ^{57}Fe absorber. We have designed and produced a dedicated TES array with ^{57}Fe absorbers for the solar axion search. The iron absorber is set next to the TES, keeping a certain distance to reduce the iron-magnetization effect on the spectroscopic performance. A gold thermal transfer strap connects them. A sample pixel irradiated from a ^{55}Fe source detected 698 pulses. In contrast to thermal simulations, we consider that the pulses include either events produced in an iron absorber or gold strap at a fraction dependent on the absorption rate of each material. Furthermore, photons deposited on the iron absorber are detected through the strap as intended. The identification of all events still needs to be completed. However, we successfully operated the TES with the unique design under iron magnetization for the first time.

One-step preparation of coal-based magnetic activated carbon with hierarchically porous structure and easy magnetic separation capability for adsorption applications

Coal-based magnetic activated carbons (CMACs) were prepared from Zhundong coal in the presence of various Fe-based additives by fast one-step physical activation method. The roles of types and doses of Fe sources for pore structures and magnetic properties of the resulting CMACs were systematically investigated. Fe species in coal promoted the development of mesopore structures, and AC-FC-3 derived from FeCl3-loaded coal (3% Fe content) possessed hierarchical pore structure with highest micropore and mesopore volumes up to 0.282 cm3·g−1 and 0.222 cm3·g−1, respectively. Considering the minimum dose of additives, the CMACs loaded a trace amount of reduced iron powder (0.5% and 1% weight ratios of coal) were prepared, and had improved micropore and mesopore structures compared with AC derived from the demineralized coal. Meanwhile, strong magnetic iron oxides (Fe3O4 and γ-Fe2O3) were generated during CO2 activation process. The CMACs derived from different Fe sources loaded coal samples with same Fe content (3% weight ratio of coal) had saturation magnetizations of 0.55–14.26 emu·g−1. Evaluated as adsorbents for Methylene Blue (MB) removal, the CMACs with hierarchical pore structure exhibited better MB adsorption capacities up to 120.3 mg·g−1. Furthermore, the magnetic properties of CMAC could accelerate the solid–liquid separation with an applied magnetic field and improve recovery efficiency of the adsorbent.

Iron nutrition in agriculture: From synthetic chelates to biochelates

Iron (Fe) is an essential micronutrient for plant growth and productivity and, among other micronutrients, is the one required in higher amounts. In most soils, Fe occurs at relatively high concentrations; nevertheless, in calcareous soils, Fe bioavailability can be very limited, thus leading plants to develop Fe deficiency symptoms. At present, Fe fertilization still represents the most frequent approach adopted in agriculture to prevent or remediate Fe chlorosis. For soil applications, Fe fertilizers are based on Fe chelated with aminocarboxylate synthetic ligands (e.g. HEDTA, EDTA, DTPA, EDDHA), which are effective in maintaining Fe in the soil solution, even in alkaline soils, and thus in increasing its bioavailability for plant uptake. Nevertheless, Fe-aminocarboxylate complexes presents some limitations, related for instance to pH-dependent effectiveness, stability, persistence in the environment and ligand exchange reactions. In this context, vegetal-derived protein hydrolysates might represent good sources of biochelating ligands for developing innovative Fe fertilizers for sustainable agriculture. Protein hydrolysates are composed by small peptides, which, on one hand, can chelate Fe via amino acid side chains, carboxylate groups of C-termini, amine groups of N-termini and N atoms of amide groups of the peptide backbone, whilst, on the other hand, small peptides can also play a signaling role, triggering the acquisition of nutrient and morphogenetic processes in plants. The present paper reviews the current state of knowledge on traditional Fe fertilizers and, on the other side, explores the possible advantages in the application of biochelates as innovative Fe fertilizers. To further corroborate the hypothesis, three experimental trials have been carried out on three horticultural crops (cucumber, tomato, and strawberry) using a Fe-biochelate as Fe source and comparing it with the widely used traditional synthetic chelate Fe-EDDHA. The results in the three crops clearly show that Fe-biochelate is, at least, as efficient as Fe-EDDHA as source of micronutrient, even under circumneutral (pH 6.0) and alkaline conditions (pH 8.0), thus proving that Fe-biochelates can be promising alternatives to synthetic Fe chelates for the Fe nutrition management of crops. Considering the potential drawbacks of synthetic chelates (e.g., leachability, persistence, remobilization of toxic metals in soil), these findings might contribute enhancing the agriculture sustainability. In addition, Fe-biochelate could also find an application in soilless cultivation systems as an alternative to synthetic Fe chelates for Fe enrichment of edible plant tissues (biofortification), increasing their nutritional value.

Synthesis and characterization of the Schiff base Fe(II) complex as a new iron source in nutrient solution

Supplying available iron (Fe) for plant growth in hydroponic nutrient solutions is a great challenge. The chelators commonly used to supply Fe in nutrient solutions have several disadvantages such as the production of photodegradable compounds and may negatively affect plant growth by toxic side effects on plants and impaired micronutrient balance. PurposeIn this study, a new complex of Fe(II)-triethylenetetramine di salicylaldehyde (Fe-TETDSA) was synthesized and applied to a nutrient solution. MethodsFe-TETDSA was synthesized by the traditional Schiff base prepration method and characterized by FT-IR, Raman, UV–Vis, photoluminescence, molar conductivity and elemental analysis. Fe-TETDSA (with single and double dose) was evaluated as a new Fe source for corns grown in nutrient solution compared to the Fe-EDTA and Fe-EDDHA, as well as FeSO4. ResultsThe Fe-TETDSA was stable in alkaline pH. Application of Fe-TETDSA chelate significantly increased root and shoot dry weight corns compared to Fe-EDTA and Fe-EDDHA. The total Fe concentration of plants supplied with Fe-TETDSA was more than those supplied with Fe-TETDSA2 and Fe-EDDHA. . Corn plants treated with Fe-TETDSA chelates also accumulated significantly higher levels of Zn (zinc) and N (nitrogen) in their shoots compared with those treated with Fe-EDTA and Fe-EDDHA. But the application of Fe-TETDSA (single and double dose) decreased Cu and Mn concentration in corns shoot. Application of Fe-TETDSA, Fe-TETDSA2 and Fe-EDDHA showed the highest SPAD index in corns leaves. ConclusionsThe results showed that Fe-TETDSA may be a sustainable alternative to traditional synthetic chelating agents such as EDTA or EDDHA in nutrient solution.

Dietary iron intake over two post-fortification periods in Brazil: data from the National Dietary Surveys 2008-2009 and 2017-2018.

We aimed to assess the dietary Fe intake and the prevalence of inadequate Fe intake over two post-fortification periods in Brazil. The intake was analysed according to sex, life stage, geographic region and stratum of family income per capita. Excluding pregnant and lactating women, this population-based study included 32749 and 44744 participants aged ≥ 10 years from the National Dietary Survey-Brazilian Household Budget Surveys 2008-2009 and 2017-2018, respectively. The National Cancer Institute method was used to predict usual dietary Fe intakes. The prevalence of Fe intake inadequacy was estimated following a probabilistic approach for women of childbearing age or with the Estimated Average Requirement cut-off point method. Over an interval of 10 years, the mean Fe intake remained almost unchanged for most sex-age groups, except for women of childbearing age. In this specific group, the prevalence of Fe intake inadequacy was > 20 % in 2008-2009 and have increased to > 25 % in 2017-2018, with the highest reductions in mean Fe intake found in the highest income strata and richest Brazilian regions. Meanwhile, the highest prevalence of Fe intake inadequacy (> 40 %) occurred among the poorest women aged 31-50 years from the lowest family income stratum, irrespective of the study period. Beans were the main Fe source, while fortified breads, pastas, pizzas, cakes and cookies contributed approximately 40 % of the Fe intake. The results provide important insights into the long-standing dietary impacts of food fortification, which can guide future (re)formulation of effective public health strategies to combat Fe deficiency.

Quick and Spontaneous Transformation between [3Fe-4S] and [4Fe-4S] Iron-Sulfur Clusters in the tRNA-Thiolation Enzyme TtuA.

Iron-sulfur (Fe-S) clusters are essential cofactors for enzyme activity. These Fe-S clusters are present in structurally diverse forms, including [4Fe-4S] and [3Fe-4S]. Type-identification of the Fe-S cluster is indispensable in understanding the catalytic mechanism of enzymes. However, identifying [4Fe-4S] and [3Fe-4S] clusters in particular is challenging because of their rapid transformation in response to oxidation-reduction events. In this study, we focused on the relationship between the Fe-S cluster type and the catalytic activity of a tRNA-thiolation enzyme (TtuA). We reconstituted [4Fe-4S]-TtuA, prepared [3Fe-4S]-TtuA by oxidizing [4Fe-4S]-TtuA under strictly anaerobic conditions, and then observed changes in the Fe-S clusters in the samples and the enzymatic activity in the time-course experiments. Electron paramagnetic resonance analysis revealed that [3Fe-4S]-TtuA spontaneously transforms into [4Fe-4S]-TtuA in minutes to one hour without an additional free Fe source in the solution. Although the TtuA immediately after oxidation of [4Fe-4S]-TtuA was inactive [3Fe-4S]-TtuA, its activity recovered to a significant level compared to [4Fe-4S]-TtuA after one hour, corresponding to an increase of [4Fe-4S]-TtuA in the solution. Our findings reveal that [3Fe-4S]-TtuA is highly inactive and unstable. Moreover, time-course analysis of structural changes and activity under strictly anaerobic conditions further unraveled the Fe-S cluster type used by the tRNA-thiolation enzyme.

Effects of dietary organic or inorganic iron concentrations on productive performance, egg quality, blood measurements, and tissue iron concentrations in aged laying hens.

The objective of the current experiment was to investigate the effects of dietary organic or inorganic iron (Fe) concentrations on productive performance, egg quality, blood measurements, and tissue Fe concentrations in aged laying hens. A total of three hundred fifty 60-week-old Hy-Line Brown laying hens were allotted to one of five dietary treatments with seven replicates. Each replicate had 10 consecutive cages. Organic Fe (Fe-Gly) or inorganic Fe (FeSO4 ) was added to the basal diet at the levels of 100 or 200 mg/kg Fe. Diets were fed on an ad libitum basis for 6 weeks. Results indicated that supplementation of organic or inorganic Fe in diets increased (p < 0.05) eggshell color and feather Fe concentrations compared with no supplementation of Fe in diets. An interaction was found (p < 0.05) between Fe sources and supplemental levels in diets for egg weight, eggshell strength, and Haugh unit. Hens fed diets supplemented with organic Fe had greater (p < 0.05) eggshell color and hematocrit than those fed diets supplemented with inorganic Fe. In conclusion, dietary supplementation of organic Fe increases the eggshell color of aged laying hens. High supplemental levels of organic Fe in diets improve egg weight in aged laying hens.

Iron(ii) carboxylates and simple carboxamides: an inexpensive and modular catalyst system for the synthesis of PLLA and PLLA-PCL block copolymers.

The combination of inexpensive Fe(ii) acetate with low molecular weight aliphatic carboxamides in situ generates an effective catalyst system for the ring opening polymerisation of lactones. PLLAs were produced in melt conditions with molar masses of up to 15 kg mol-1, narrow dispersity (Đ = 1.03), and without racemisation. The catalytic system was investigated in detail with regard to Fe(ii) source, and steric and electronic effects of the amide's substituents. Furthermore, the synthesis of PLLA-PCL block copolymers of very low randomness was achieved. This commercially available, inexpensive, modular, and user-friendly catalyst mixture may be suitable for polymers with biomedical applications.

Chemical Cyclic Amplification: Hydroxylamine Boosts the Fenton Reaction for Versatile and Scalable Biosensing

Nucleic acid detection is undoubtedly one of the most important research fields to meet the medical needs of genetic disease diagnosis, cancer treatment, and infectious disease prevention. However, the practical detection methods based on biological amplification are complex and time-consuming and require highly trained operators. Herein, we report a simple, rapid, and sensitive method for the nucleic acid assay by fluorescence or naked eye using chemical cyclic amplification. The addition of hydroxylamine (HA) during the Fenton reaction can continuously generate hydroxyl radicals (•OH) via Fe3+/Fe2+ cycle, termed as "hydroxylamine boosts the Fenton reaction (Fenton-HA system)". Meanwhile, the reducing substances, such as terephthalic acid or o-phenylenediamine, react with •OH to generate oxidized substances that can be recognized by the naked eye or detected by fluorescence so as to realize the detection of Fe3+. The concentration of Fe3+ has a good linear relationship with fluorescence intensity in the range of 0.1 to 100 nM, and the limit of detection is calculated to be 0.03 nM (S/N = 3). Subsequently, Fe was introduced into the nucleic acid hybridization system after the Fe source was transformed into Fe3+, and the nucleic acids were indirectly determined by this method. This Fenton-HA system was used for sensing HIV-DNA and miRNA-21 to verify the validity of this method in nucleic acid detection. The detection limits were as low as 2.5 pM for HIV-DNA and 3 pM for miRNA-21. We believe that our work has unlocked an efficient signal amplification strategy, which is expected to develop a new generation of highly sensitive chemical biosensors.

A Stepwise-Confined Self-Reduction Strategy to Construct a Dynamic Nanocatalyst for Boosting Tumor Catalytic Therapy

Fenton/Fenton-like reactions involve the transformation of hydrogen peroxide to hydroxyl radicals to kill tumors. However, the current Fenton/Fenton-like biocatalyst always suffers from low therapeutic efficacy owing to the slow reaction rate of low-valence metal/high-valence metal cycles. Herein, a “stepwise-confined self-reduction” strategy is proposed to construct a dynamic self-reduction dual-metal (Cu/Fe) nanocatalyst in the thiols/disulfide bonds-doped micellar-organosilica framework. The preferential self-reduction of Fe and Cu sources by thiol groups and the dynamic reduction reaction between them in the confined framework produce low-valence and highly active Fe2+ and Cu+ sites in the bimetallic Cu/Fe nanoclusters. The responsively synergistic catalysis of the dual-metal nanocatalyst to generate reactive oxygen species in an acidic and reductive tumor microenvironment is evaluated. Furthermore, the cascade catalysis-induced ferroptosis mechanism through the downregulation of glutathione and glutathione peroxidase 4 protein levels and the overload of Fe2+ is also studied. The in vitro and animal experiments demonstrate that the synergistic catalysis can significantly inhibit tumor growth while ensuring the safety of treatment. This work provides a versatile pathway for the precise construction of bioapplicable multimetal-based nanocatalysts for efficient and safe diagnosis and treatment of tumors.

Highly sensitive and selective serotonin (5-HT) electrochemical sensor based on ultrafine Fe3O4 nanoparticles anchored on carbon spheres

Neurotransmitter serotonin (5-HT) is involved in various physiological and pathological processes. Therefore, its highly sensitive and selective detection in human serum is of great significance for early diagnosis of disease. In this work, employing iron phthalocyanine as Fe source, ultrafine Fe3O4 nanoparticles anchored on carbon spheres (Fe3O4/CSs) have been prepared, which exhibits an excellent electrochemical sensing performance toward 5-HT. With carbonecous spheres turned into conductive carbon spheres under the heat treatment in N2 atmosphere, iron phthalocyanine absorbed on their surfaces are simultaneously pyrolysised and oxidized, and finally transformed into ultrafine Fe3O4 nanoparticles. Electrochemical results demonstrate a high sensitivity (5.503 μA μM−1) and a low detection limit (4 nM) toward 5-HT for as-prepared Fe3O4/CSs. In combination with the morphology and physicochemical property of Fe3O4/CSs, the enhanced sensing mechanism toward 5-HT is disscussed. In addition, the developed electrochemical sensor also displays a good sensing stability and an anti-interferent ability. Further applied in real human serum samples, a satisfactory recovery rate is achieved. Promisingly, the developed electrochemical sensor can be employed for the determination of 5-HT in actual samples.

Integrated O, Fe, and Ti isotopic analysis elucidates multiple metal and fluid sources for magnetite from the Ernest Henry Iron oxide copper gold (IOCG) Deposit, Queensland, Australia

Iron oxide copper gold (IOCG) deposits are globally important sources of Cu; however, their origins remain poorly understood with respect to the metal and fluid sources involved in their formation. In this work, we utilize integrated Fe, Ti, and O isotopic data for magnetite to trace major metal and fluid inputs for the Proterozoic-aged Ernest Henry IOCG deposit—the largest known IOCG deposit in the Cloncurry District, Queensland, Australia. Magnetite separates from ore stage and pre-ore biotite-magnetite (bt-mgt) and magnetite-actinolite (mgt-act) alteration assemblages from Ernest Henry were analyzed for their O, Fe, and Ti isotope abundances, reported as δ18O (VSMOW), δ56Fe (IRMM-14), and δ49Ti (OL-Ti). Select magnetite samples were also analyzed for 17O (reported as Δ’17O0.5305) and range from −0.118 to −0.056 ‰—suggesting evaporitic input. The δ18O values from ore stage (+1.57 to +7.36 ‰), bt-mgt (+0.34 to +5.68 ‰), and mgt-act (+1.68 to +2.10 ‰) samples are consistent with a magmatic-hydrothermal origin for ore and pre-ore mineralizing fluids at Ernest Henry; non-magmatic δ18O values > c. 5 ‰ may be explained through localized carbonate wall rock assimilation. Despite this, δ56Fe values for ore stage (−0.50 to +0.33 ‰), bt-mgt (−0.65 to +0.38 ‰), and mgt-act (−0.26 to +0.30 ‰) magnetite are generally isotopically lighter than the accepted range (c. +0.06 to +0.49 ‰) for igneous and magmatic-hydrothermal magnetite and exhibit a relatively large range of c. 1 ‰, suggesting Fe source mixing within the deposit. Ore stage magnetite δ49Ti (−1.64 to + 3.79 ‰; avg: +1.49 ‰; 2σ = 2.63 ‰) compositions are generally higher and more variable than either the bt-mgt (-0.44 to + 1.49 ‰; avg: +0.62 ‰; 2σ = 1.13 ‰) or mgt-act (+0.27 to + 1.89 ‰; avg: +1.05 ‰; 2σ = 1.56 ‰) and suggest that Ti isotope fractionation occurred due to differential mobility in the fluid. The data are best explained by models invoking both magmatic and non-magmatic metal and fluid input. Fluid flow channeled between the footwall and hanging wall shear zones introduced non-magmatic Fe that may have been leached from local mafic units by magmatic-hydrothermal fluids, resulting in neoformed and regeneratively replaced magnetite with magmatic δ18O, but non-magmatic δ56Fe values during pre-ore alteration. These fluids may have mixed with Fe-poor evaporitic fluids prior to magnetite formation. Later magmatic Fe and O contributions during ore stage mineralization resulted in magnetite with variable δ56Fe and irresolvable δ18O overprinting. Ernest Henry is the first known example of an IOCG deposit with a major leached metal component identified through metal stable isotope geochemistry.

Scalable electrodeposition of NiFe-based electrocatalysts with self-evolving multi-vacancies for high-performance industrial water electrolysis

Water electrolysis is a promising technique for green hydrogen production to achieve the global strategic goal of carbon neutrality. Herein, we propose an optimized-electrodeposition set-up in Ethaline-based deep eutectic solvent (DES) for the electrochemical preparation of NiFe-based catalysts. The developed synthesis procedure involves the anodic dissolution of Fe plates to provide Fe sources, which are gradually incorporated into the in-situ grown Ni films to fabricate NiFe-based electrodes. Our findings show that introducing nitrate ions coupled with electrochemical water oxidation can induce the formation of multi-vacancy-rich NiFe-based catalysts with outstanding water splitting performance in quasi-industrial conditions. A simulated industrial anion exchange membrane (AEM)-based device loaded with our NiFe-based electrocatalysts requires only 1.73 Vcell to reach 1000 mA cm−2 in 5.0 M KOH at 60 °C and works continuously for up to 200 h. The present work provides a means for the scalable synthesis of self-supported NiFe-based catalysts for industrial water splitting.

Distinguishing the influence of sediments, the Congo River, and water-mass mixing on the distribution of iron and its isotopes in the Southeast Atlantic Ocean

Iron (Fe) is an essential micronutrient for primary production, and Fe isotopic composition (δ56Fe) has become a widely used oceanographic tool for determining sources and evaluating the biogeochemical cycling of dissolved Fe (dFe) in the oceans. Here, we present dFe concentrations and δ56Fe from three unique oceanographic settings (a river dominated margin, a highly productive coastal upwelling margin, and a meridional open ocean transect) collected during the South Atlantic GEOTRACES cruise GA08 along the Namibian-Congo margin. In the North, the offshore Congo River plume dominates the surface ocean, resulting in elevated surface dFe concentrations up to 1000 km from the river mouth, corresponding to increasing δ56Fe values (+0.33 to +0.95‰) with distance from the river outlet. We attribute this unusual and extensive offshore delivery of heavy Fe to dFe preservation by complexation with organic ligands, coupled with rapid off-shelf advection. In the South, the highly productive Benguela Upwelling System produces oxygen depleted to seasonally anoxic bottom waters on the continental shelf, resulting in extremely high subsurface dFe concentrations (up to 42 nmol kg-1) and remarkably light δ56Fe values (as low as -3.31‰), characteristic of dFe(II) production and mobilization via reductive dissolution of Fe oxyhydroxides in sediments. Away from the continental margins, surface waters carry predictably low dFe concentrations (∼0.1 nmol kg-1), associated with isotopically heavy Fe linked to dust deposition and biological uptake. In subsurface waters, and away from Fe sources, we find a remarkably coherent relationship between water masses and dissolved δ56Fe signatures along the GA08 section. Using δ56Fe data from GA08 and water mass analysis, we assign endmember signatures of -0.12 ± 0.02‰ for AAIW, +0.71 ± 0.09‰ for NADW, and +0.35 ± 0.12‰ for AABW. Overall, we find that the distribution of δ56Fe in the South Atlantic can largely be explained by water mass mixing, with some overprinting by local processes and sources, suggesting that dissolved δ56Fe signatures can be used as tracers of deep ocean Fe transport.

Continuously feeding fenton sludge into anaerobic digesters: Iron species change and operating stability

Fenton sludge generated from the Fenton process contains a large number of ferric species and organic pollutants, which need to be properly treated before discharge. In this study, Fenton sludge as an Fe(III) source for dissimilatory iron reduction (DIR) was continuously added with increasing dosage into an anaerobic digester to enhance the treatment. Results showed continuously feeding Fenton sludge to the anaerobic digester did not deteriorate the performance and increased methane production and COD removal rate by 2.2 folds and 14.0%, respectively. The Fe content of sludge in the digester increased from 40.25 mg/g (dry weight) to 131.53 mg/g after continuously feeding for 77days, and then declined to 109.17 mg/g when the feeding was stopped. Mass balance analysis showed that 20.5 to 48.4% of Fe in the Fenton sludge was released to the effluent. After experiment, the ratio of reducible Fe species to the total Fe was 75.1%, which maintained the high activity in DIR. Microbial community analysis showed that iron-reducing bacteria were enriched with the addition of Fenton sludge and the sludge in the digester had a higher conductivity and capacitance to strengthen the electron transfer of DIR. All results suggested that feeding Fenton sludge into anaerobic digesters was a feasible method to dispose of Fenton sludge as well as to enhance the performance of anaerobic digestion.

Municipal green waste promotes iron release from steelmaking slag in water

Shortage of soluble Fe in seawater is a limiting condition for benthic seaweeds growth. Utilizing steelmaking slag as the Fe source for seaweeds growth has been proposed. Aiming to find a cost-effective method to promote Fe release, we investigate the effect of adding municipal green wastes. By conducting leaching experiments in freshwater, a sharp improvement in Fe release was observed with the addition of tangerine peel together with steelmaking slag. The flavonoids supplied from the tangerine peel, vicenin-2, apigenin, hesperidin, vitexin, hesperetin and diosmin were observed to have a promotion effect on Fe release. Formation of stable flavonoid-Fe(II) chelates changes the thermodynamic property of Fe(II) in water and disturbs the equilibrium between Fe(II) in slag and Fe(II) in water, which promotes Fe release from slag. These results demonstrate the feasibility to develop a technology for Fe supply in seawater by utilizing the mixture of steelmaking slag and municipal green wastes.

The source and depositional environment of early Silurian iron formation in NW China: Constraints from element and isotope (Fe, C, O) geochemistry

Phanerozoic iron formations (IFs) provide a unique opportunity to understand both the contemporaneous chemical composition and redox state of seawater where they precipitated. However, the absence of detailed reports of Phanerozoic IFs inhibits a robust understanding of their depositional conditions and dominant Fe sources. Here, we describe a hematite- and siderite-rich IF from Kukeate hosted within lower Silurian submarine siliciclastic and carbonate sedimentary succession in NW China. The chemical composition of our analysed samples is dominated by high TFe2O3 and variable SiO2 contents, with low Al2O3, TiO2, Sc, Nb, Th, and Zr concentrations, indicating an authigenic origin. Distinct depletion in LREE relative to HREE, super-chondritic Y/Ho ratios, and slightly positive Gd anomalies, are diagnostic for derivation from surface seawater. The lack of strong positive Eu anomaly, along with coupled Fe and O isotopic characteristics for the hematite, point to a significant low-T hydrothermal input. Slightly negative to no Ce anomalies, weakly negative to mildly positive Eu anomalies, homogeneous δ56Fe values (near zero), and large positive δ13CV-PDB excursions, together suggest that there exists a dynamic redoxcline, which separated oxic surface water and ferruginous deeper water conditions, where dissolved Fe2+ in deep, reducing, Fe-rich hydrothermal fluids, was oxidized and precipitated as Fe(OH)3 in shallow oxygenated seawater, leading to the formation of hematite. Accordingly, the occurrence of Kukeate IF suggests intermittent ferruginous deeper water conditions during the early Silurian.

Defect and interface co-steering ultra-wide microwave absorption and superior thermal conductance of TiO2/Fe/C nanocomposites

To solve the problems of electromagnetic interference and heat dissipation generated in miniaturized and highly integrated modern electronics, we pioneered the use of TiO2/Fe/C nanocomposites as advanced heat conduction-microwave absorption integrated materials (HCMWAIMs). The TiO2/Fe/C nanocomposites were produced by a simple one-step pyrolyzation route using iron pentacarbonyle (Fe(CO)5) as C and Fe sources and nanoscale titanium dioxide (P25) as a precursor. The phase structure, Ti/Fe atomic ratios, and defects of the TiO2/Fe/C nanocomposites were expediently adjusted by controlling the Fe(CO)5 vol In the case where the Fe(CO)5 vol was increased, the electric conductivity increased linearly with the increasing Fe/Ti atomic ratio, while the heat conductivity changed in a reversed U shape. Results showed that the TiO2/Fe/C nanocomposites prepared by the combination of TiO2 with Fe and C possess higher heat conductivity (1.870 W/(m⋅K)), excellent electric insulation (0.593 S/m), larger absorption bandwidth/thickness (ABW/d) values (5.6 GHz/mm), higher absorption (−42.59 dB), and thinner films (1.2 ∼ 2.1 mm) than other previously reported materials. The excellent comprehensive capabilities result from the combined action of interfaces and defects. The as-obtained TiO2/Fe/C nanocomposites are expected to be efficient HCMWAIMs used in electronic devices.

Two Fe mining sub-products and three thiol compounds alleviate Fe deficiency in soybean (Glycine max L.) grown in a calcareous soil in greenhouse conditions

PurposeThe aim of this work was to test the hypothesis that Fe mining sub-products and thiols can alleviate a moderate Fe-deficiency in the Strategy I species soybean (Glycine max) grown in a calcareous soil in greenhouse conditions.MethodsCombinations of three Fe sources [Fe(III)-EDDHA and two Fe mining sub-products, one containing Fe oxides and FeS2 and the other Fe oxides], and three thiols (glutathione, dithiothreitol and thiophenol) were applied in solution to the soil, three times in a 55 day period, and different parameters related to Fe deficiency were measured. The thiol-mediated solubilization of Fe from the Fe mining sub-products was assessed by measuring in the solution total Fe and the reducible Fe pool using an Fe(II) chelator.ResultsApplication of Fe-EDDHA, the two Fe mining sub-products and the three thiols relieved the Fe deficiency symptoms to different extents, increased the Fe concentrations and contents throughout the plant and changed the redox state of leaves and roots, as judged from the changes in reduced and oxidized glutathione, ascorbate and antioxidant enzymes. When using Fe(III)-EDDHA, the addition of thiols led to a better leaf regreening. However, the addition of thiols did not cause further regreening in the case of the Fe mining sub-products, in spite of being able to solubilize Fe from them.ConclusionApplication of Fe-mining sub-products, thiols and the combination of Fe(III)-EDDHA and thiols could be used to alleviate moderate Fe deficiency in G. max grown in a calcareous soil.