What is 2 line ferrihydrite?

Two-line ferrihydrite (hereafter called ferrihydrite; bulk composition 5Fe2O3·9H2O) is a poorly crystalline Fe(III) oxyhydroxide that occurs as very small (2−4 nm) spherical particles in an aggregated form in natural settings (1-3).

What is ferrihydrite used for?

Ferrihydrite is the precursor for most iron oxides in soil, and it subsequently transforms to more stable phases such as goethite (Feitknecht and Michaelis, 1962). The structure of ferrihydrite has been the subject of considerable interest and several structural models have been proposed for the mineral.

How is ferrihydrite formed?

In the natural environment ferrihydrite often forms by oxidation of Fe(II)aq at near neutral pH, (1) and under these conditions Fe13, if formed, would be expected to be highly transitory. In acidic conditions, such as in acid mine runoff, Fe13 may be more persistent.

Is ferrihydrite magnetic?

These observations suggest that ferrihydrite is a potential magnetic remanence carrier under ambient environmental conditions. Measurements of mineral mixtures show that magnetic techniques can discriminate between ferrihydrite and goethite at low concentrations.

Is ferrihydrite a mineral?

Ferrihydrite (Fh) is a widespread hydrous ferric oxyhydroxide mineral at the Earth’s surface, and a likely constituent in extraterrestrial materials. It forms in several types of environments, from freshwater to marine systems, aquifers to hydrothermal hot springs and scales, soils, and areas affected by mining.

Is ferrihydrite rusty?

Ferrihydrite is a metastable mineral. Under reducing conditions as those found in gley soils, or in deep environments depleted in oxygen, and often with the assistance of microbial activity, ferrihydrite can be transformed in green rust, a layered double hydroxide (LDH), also known as the mineral fougerite.

What is ferferrihydrite?

Ferrihydrite (Fh) is a widespread hydrous ferric oxyhydroxide mineral at the Earth’s surface, and a likely constituent in extraterrestrial materials. It forms in several types of environments, from freshwater to marine systems, aquifers to hydrothermal hot springs and scales, soils, and areas affected by mining.

How much H2O is in a gram of ferrihydrite?

In the case of a surface area of A = 650 m 2 /g Fh, the amount of chemisorbed water ( N H 2 O = 6.0 ± 0.5 nm −2) is equal to 0.12 ± 0.01 g H 2 O/g Fh. Per gram, ferrihydrite will contain 0.12 g chemisorbed H 2 O and 0.88 g mineral core (e.g. FeOOH).

What is the molar mass of ferrihydrite nanoparticles?

Per gram, ferrihydrite will contain 0.12 g chemisorbed H 2 O and 0.88 g mineral core (e.g. FeOOH). The latter is equivalent to 9.9 mmol Fe per gram Fh and this yields a molar mass for the nanoparticles of M ∼ 101 ± 1 g/mol Fe.

What is the diffraction model of ferrihydrite and hydromaghemite?

The diffraction model has been confirmed in 2002 by Neutron diffraction. A single phase model for both ferrihydrite and hydromaghemite has been proposed by Michel et al., in 2007-2010, based on pair distribution function (PDF) analysis of x-ray total scattering data.