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Microwave sintering is a key technology for future lunar habitats, which has been verified by various lunar soil simulant experiments. However, nanophase iron (np-Fe0), a unique component of the real lunar regolith, has been ignored in previous studies of the microwave sintering of lunar soil simulants. In this study, microwave-sintering experiments of lunar soil simulant CLRS-2 with and without np-Fe0 at different temperatures were conducted. A comparison of the microstructure and chemical composition of sintered products indicates that all products of samples with 1.0 wt% np-Fe0 exhibit better properties than those without np-Fe0 after heating at equivalent temperatures. Adding np-Fe0 to the lunar soil simulant CLRS-2 couples well with microwaves, which may increase the real heating temperature in a sample, resulting in the product being solidified at 700 °C and a relatively dense product forming at 900 °C, thus improving the sintering efficiency. This study suggests that microwave sintering is an effective potential technology for future lunar habitats and road hardening because of the wide distribution of np-Fe0 in the lunar regolith. The technical parameters given in this study can provide an important guide for future lunar construction by microwave sintering. [ABSTRACT FROM AUTHOR]

Finding a good sorbent for phosphorus (P) recovery from the aquatic environment is critical for preventing eutrophication and providing P resources. The activated iron system (mainly consisted of zero-valent iron (ZVI), Fe 3 O 4 and Fe 2+ ) has been reported to exhibit a favorable performance towards various contaminants in wastewater, but its effect on P recovery has not been studied systematically. In this study, we used Fe 2+ -nitrate pretreatment reaction to prepare the activated iron system and then applied it to P recovery. Results show that more than 99% P was removed from water in 60 min; co-existing anions (NO 3 − , Cl − and SO 4 2− ) and natural organic matter (NOM) had little effect on P removal. The P removal capacity of activated iron system is very high compared with currently reported sorbents. Externally-supplied Fe 2+ plays an important role on P removal in the system. Regeneration study shows that the activated iron system exhibited stable P recovery ability by using 0.1 M NaOH solution. Various methods were applied to characterize the ZVI and iron corrosion, and results conclude that sorption precipitation, and co-precipitation contribute to P removal. This method will be promising and have an application potential in the field for efficient and cost-effective recovery of P with cheap microscale zero valent iron. [ABSTRACT FROM AUTHOR]

[Display omitted] • Yudongzi BIFs were formed at ca. 2.8 Ga, and suffered two-stage metamorphism. • Yudongzi BIFs were formed on the back–arc basin setting. • Yudongzi complex combined to Yangtze Block later than Paleoproterozoic. The Yudongzi banded iron formations (BIFs) are widely spread in the Neoarchean Yudongzi Group of the Bikou Terrane, Central China. Their sedimentary and metamorphic ages, however, remain controversial, either their forming or reworking processes. In this contribution, we conducted an integrated study of zircon U-Pb-Hf isotope geochemistry, as well as mineral and bulk-rock geochemistry on the Heishan'gou iron deposit, the largest iron deposit of the Yudongzi BIFs, to constrain their formation and metamorphism ages, source of ore-forming material and tectonic setting. Mineral chemistry analysis indicates that the amphibolite, host-rock of the Heishan'gou deposit suffered amphibolite facies metamorphism. LA-ICP-MS U-Pb dating of zircon grains from orthometamorphic host-rocks suggests that the Heishan'gou deposit was formed at the early Neoarchean (2781 ± 43 Ma for amphibolite and 2776 ± 43 Ma for plagioclase-hornblende schist), and metamorphosed at ca. 2480 ± 26 Ma and 1818 ± 44 Ma, respectively. The low contents of aluminum, titanium and high field strength elements in BIFs suggest that they are detritus-free marine chemical precipitates. The rare earth elements (REE) and Y patterns of BIFs display seawater-like signatures with light REE depletion, and positive La and Y anomalies. Meanwhile, their positive Eu anomalies suggest that submarine hydrothermal fluid might also be involved in the precipitation of BIFs. Combined with zircon Hf isotope data and geochemical compositions of amphibolites, it is proposed that the Yudongzi BIFs should be formed at back-arc basin setting. Compared with the representative Archean continent nucleus of the Yangtze Block (Kongling Complex), the Yudongzi Complex experienced distinct crustal evolutionary history. It indicates that the Yudongzi Complex might represent the accretionary block combined to the Yangtze continental nucleus later than the Paleoproterozoic. [ABSTRACT FROM AUTHOR]

Abstract A novel dicarboxyl-functionalized iron cryptate with a 2,2-pyridine unit has been synthesized, which displays outstanding electrochemical properties in water as a potential biosensing probe. Taking the silver ion (Ag+) as an example, we report a novel Ag+ assay by recording the electrochemical signals of Fe cryptate. In summary, a hairpin-structured DNA probe is designed and modified with the synthesized Fe cryptate. In the absence of Ag+, this is absorbed on the surface of a reduced graphene oxide modified electrode and a significant electrochemical response is obtained. In the presence of Ag+, cytosine–cytosine mismatches in the DNA probe recognize target ions and it is transformed into a conformation which cannot resist digestion by exonuclease III. As a result, Fe cryptate is released and Ag+ is recycled for continuous DNA digestion. By analyzing the reduced electrochemical signals of Fe cryptate, it is possible to quantify the target ions. Graphical abstract Unlabelled Image Highlights • A novel dicarboxyl-functionalized iron cryptate is synthesized. • Fe cryptate is modified with a DNA probe and the electrochemical response is studied. • A sensitive and selective method for Ag+ assay is developed. [ABSTRACT FROM AUTHOR]

Aerosol soluble iron (Fe) is crucial in the biogeochemical cycle and atmospheric processing. In this study, soluble Fe and their solubility in fine particles (PM 2.5) were investigated over Xi'an, China to insight the iron sources and the roles in aerosol formation. Our results showed that most Fe in PM 2.5 was insoluble (Fe solubility: 25.5 ± 11.3%). Seasonal variations exhibited that the highest soluble Fe(II) showed in winter (308.9 ng m−3) and the highest Fe(III) levels were in summer (116.3 ng m−3). Source identification of soluble Fe illustrated that industrial coal combustion contributed most in summer, whereas mineral dust, biomass burning, and coal combustion dominated in spring, autumn, and winter, respectively. Moreover, strong correlations between soluble Fe and water-soluble inorganic ions suggested soluble Fe is related to not only primary sources but also secondary formations. Furthermore, a negative correlation (R = −0.56) was observed in winter between Fe(III) and SO 4 2−, indicating that the oxidation pathway of Fe(III) catalysis should play a vital role in sulfate formation in winter. In addition, secondary brown carbon presented positive correlations with soluble Fe(II), while negatively correlated with soluble Fe(III), potentially suggested an important pathway for the formation of secondary BrC. Our study provides a broader understanding of Fe solubility and their roles in atmospheric chemical processing. [Display omitted] • Field observation was conducted to reveal the role of soluble Fe in secondary aerosol formations. • Fe(II) was the highest in winter, while the highest Fe(III) was in summer. • Both biomass burning and coal combustion contributed to soluble Fe. • Fe-chemistry played a vital role in winter sulfate and secondary BrC formations. [ABSTRACT FROM AUTHOR]

In female, inadequate iron supply is a highly prevalent problem that often leads to iron-deficiency anemia. This study aimed to understand the effects of pregnancy and lactation on iron metabolism. Rats with different days of gestation and lactation were used to determine the variations in iron stores and serum iron level and the changes in expression of iron metabolism-related proteins, including ferritin, ferroportin 1 (FPN1), ceruloplasmin (Cp), divalent metal transporter 1 (DMT1), transferrin receptor 1 (TfR1), and the major iron-regulatory molecule—hepcidin. We found that iron stores decline dramatically at late-pregnancy period, and the low iron store status persists throughout the lactation period. The significantly increased FPN1 level in small intestine facilitates digestive iron absorption, which maintains the serum iron concentration at a near-normal level to meet the increase of iron requirements. Moreover, a significant decrease of hepcidin expression is observed during late-pregnancy and early-lactation stages, suggesting the important regulatory role that hepcidin plays in iron metabolism during pregnancy and lactation. These results are fundamental to the understanding of iron homeostasis during pregnancy and lactation and may provide experimental bases for future studies to identify key molecules expressed during these special periods that regulate the expression of hepcidin, to eventually improve the iron-deficiency status. [ABSTRACT FROM AUTHOR]

Nanoscale zero-valent iron (nZVI) has been extensively used to remove various pollutants. However, the rapid deactivation due to aggregation and surface passivation severely limits its practical application. In this study, a novel composite with nZVI supported by pinecone biochar (nZVI-PBC) was successfully synthesized and used for the removal of high concentration Cr(VI) from aqueous solution in the presence of Shewanella oneidensis MR-1 (MR-1). The results showed that the nZVI-PBC coupling with MR-1 (nZVI-PBC/MR-1) exhibited an excellent removal performance for high concentration Cr(VI) compared to the nZVI-PBC alone. Under optimal conditions, 100 mg/L Cr(VI) could be removed completely by nZVI-PBC/MR-1 within 48 h, while only 39.50% of Cr(VI) was removed by nZVI-PBC alone. The improvement of Cr(VI) removal is due to the dissolution of the surface passivation layer of nZVI-PBC, formation of sorbed Fe(II) in the presence of MR-1, and an important role of extracellular polymeric substance (EPS) derived from MR-1. X-ray photoelectron spectroscopy (XPS) and Cr K-edge X-ray absorption near-edge structure spectra (XANES) confirmed that most Cr(VI) was reduced to insoluble Cr(III) and formed Cr 2 O 3 , Cr x Fe 1-x (OH) 3 and FeCr 2 O 4 precipitates, and a small amount of unreduced Cr(VI) was immobilized through adsorption and complexation. The results suggest that nZVI-PBC/MR-1 can effectively overcome the limitations of nZVI and achieve highly efficient removal of high concentration Cr(VI). [Display omitted] • nZVI-PBC coupling with MR-1 exhibited an excellent capacity for Cr(VI) removal. • Sorbed Fe(II) could act as a strong reductant to reduce Cr(VI) to Cr(III). • The EPS derived from MR-1 play an important role in Cr(VI) removal. • nZVI-PBC coupling with MR-1 overcomes the aggregation and passivation of nZVI. • The mechanism of Cr(VI) removal by nZVI-PBC coupling with MR-1 was proposed. [ABSTRACT FROM AUTHOR]