[1] The ‘‘hard’’ isothermal remanent magnetization (HIRM) and the S-ratio are widely used in environmental magnetism to quantify the absolute and relative concentrations, respectively, of antiferromagnetic minerals (hematite and goethite) in mineral mixtures. We demonstrate that synthetic Al-substituted hematite and goethite exhibit a wide range of coercivities, which significantly influences t...

Introduction: Mapping the type and distribution of hydrated mineralogy is one way to track the aqueous history of Mars. Sulfates are a potentially good tracer of past climate because they form by aqueous processes , so their presence, volume, and process of formation can characterize how much water was available. The sulfates in Valles Marineris (monohydrated Mg or Fe sulfate and polyhydrated s...

Application of in situ UV-Vis absorption spectroscopy and ex situ X-ray photoelectron spectroscopy (XPS) makes it possible to resolve the controversies about the electronic properties of hematite (α-Fe(2)O(3)) nanoparticles (NPs) and, on this basis, to rationalize the unusual dependence of aquatic (bio)chemistry of these NPs on NP size. 2-Line ferrihydrite (FH) is also included in the study as ...

The management of dredged sediments is a priority issue in the Mediterranean sea where sediments are historically polluted. The aims of this study were to evaluate the toxicity of port sediment samples and the effect of three mineral additives (hematite, zerovalent iron (ZVI) and natural zeolite (NZ)) on sediment elutriate toxicity. Four sediments (A, B, C and D) were provided by port authoriti...

Natural organic matter (NOM) enhancement of the biological reduction of hematite (alpha-Fe2O3) by the dissimilatory iron-reducing bacterium Shewanella putrefaciens strain CN32 was investigated under nongrowth conditions designed to minimize precipitation of biogenic Fe(II). Hydrogen served as the electron donor. Anthraquinone-2,6-disulfonate (AQDS), methyl viologen, and methylene blue [quinones...

Abstract Weakly magnetic hematite (α‐Fe 2 O 3 ) nanoparticles were synthesized by heating an amorphous polymer supported iron(III) complex ( Fe_POL at 400 °C for 4 h in air. The growth of (NPs) was studied PXRD, the from 150 to 25 intervals, revealing that, all temperatures, only crystalline phase detected is hematite. Conversely, annealing under nitrogen, yielded a material containing wüstite ...

the present experiments is deciding to study the effect of hematite and volcanic ash on growth and physiological traits in sorghum factorial in a randomized complete design with  treatments and replications treatments consisted of volcanic ash concentrations (0, 0.25 and 0.5 g), hematite at three concentrations (0, 0.25 and 0.5 g), respectively. the results showed that the largest radicle and p...

The fate of the oxoanion arsenate in diverse systems is strongly affected by its adsorption on the surfaces of iron (oxyhydr)oxide minerals. Predicting this behavior in the environment requires an understanding of the mechanisms of arsenate adsorption. In this study, the binding site and adsorption geometry of arsenate on the hematite (012) surface is investigated. The structure and termination...

The Conceição mine, which is located in the Itabira district, southern São Francisco craton, is a rare example of gold and palladium mineralization hosted by jacutinga, an altered Lake Superior-type iron-formation. The mine sequence consists of three metamorphosed lithostratigraphic units, which are from the oldest to the youngest: (1) an Archean volcanosedimentary sequence, (2) a Paleoproteroz...

Here we predict the existence of a linear bulk spin photovoltaic effect, where spin currents are produced in antiferromagnetic materials as a response to linearly polarized light, and we describe the symmetry requirements for such a phenomenon to exist. This effect does not depend on spin-orbit effects or require inversion symmetry breaking, distinguishing it from previously explored methods. W...