Iron deficiency in plants is caused by a low availability of iron in the soil, and its main visual symptom is leaf yellowing due to a decrease in chlorophyll content, along with a reduction in plant growth and fruit quality. Foliar sprays with Fe compounds are an economic alternative to the treatment with expensive synthetic Fe-chelates applied to the soil, although the efficacy of foliar treat...

The production of small quantities of Fe(II) during the initial phase of microbial Fe(III) reduction greatly increased the amount of Fe(III) that could be extracted from freshwater sediments with oxalate. This finding and other evidence suggest that the oxalate-extractable Fe(III) that is unavailable for microbial reduction in anoxic sediments is not in the form of mixed Fe(III)-Fe(II) forms, a...

We studied the effects of humic substances (HS) on the sorption of Fe(II) onto Al-oxide and clay sorbents at pH 7.5 with a combination of batch kinetic experiments and synchrotron Fe K-edge EXAFS analyses. Fe(II) sorption was monitored over the course of 4 months in anoxic clay and Al-oxide suspensions amended with variable HS types (humic acid, HA; or fulvic acid, FA) and levels (0, 1, and 4 w...

Reactions of aqueous Fe(II) with Fe and Mn oxides influence heavy metal mobility, transformation of trace organics, and important elemental cycles as Fe precipitates form or dissolve, and as electrons move between aqueous and solid phases. Our objective was to characterize reactions of Fe(II) with important metal oxides, using a suite of complementary tools to investigate the extent and underly...

Three μ-X bridged diiron octapropylporphyrazine complexes having Fe(III)-O-Fe(III), Fe(+3.5)-N[double bond, length as m-dash]Fe(+3.5) and Fe(IV)[double bond, length as m-dash]C[double bond, length as m-dash]Fe(IV) structural units have been prepared and characterized by UV-vis, EPR, X-ray absorption spectroscopy and electrochemical methods. Single crystals of all the complexes were obtained fro...

Women of childbearing age are at risk of Fe deficiency if insufficient dietary Fe is available to replace menstrual and other Fe losses. Haem Fe represents 10-15 % of dietary Fe intake in meat-rich diets but may contribute 40 % of the total absorbed Fe. The aim of the present study was to determine the relative effects of type of diet and menstrual Fe loss on Fe status in women. Ninety healthy ...

A theoretical investigation of the relationship between chemical composition and electronic structure was performed on the nonstoichiometric iron sulfide, mackinawite (Fe(1+x)S), which is isostructural and isoelectronic with the superconducting Fe(1+x)Se and Fe(1+x)(Te(1-y)Se(y)) phases. Even though Fe(1+x)S has not been measured for superconductivity, the effects of stoichiometry on transport ...

Metallic iron (Fe) is often reported as a reducing agent for environmental remediation. There is still controversy as to whether Fe plays any significant direct role in the process of contaminant reductive transformation. The view that Fe is mostly a generator of reducing agents (e.g. H, H2 and Fe) and Fe oxyhydroxides has been either severely refuted or just tolerated. The tolerance is based o...

In the presence of iron (Fe), dissolved organic matter (DOM) may bind considerable amounts of arsenic (As), through formation of Fe-bridged As-Fe-DOM complexes and surface complexation of As on DOM-stabilized Fe-colloids (collectively referred to as As-Fe-DOM complexation). However, direct (e.g., chromatographic and spectroscopic) evidence and fundamental kinetic and stability constants have be...

Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II) to Fe(III) and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(I...