Oxidation of Fe²⁺ Ions in Sulfate-and Chloride-Containing Aqueous Medium Available to Purchase

To study the effect of $SO42−$ ions on the oxidation of Fe²⁺ ions in a sulfate- and chloride-containing aqueous medium, the final products formed by changing the ratio between $SO42−$ and Cl⁻ ions were investigated using Mössbauer spectroscopy and x-ray diffraction. The overall oxidation reaction of Fe²⁺ ions was composed of three distinct stages. The increase of [$SO42−$]/[Cl⁻] in the solution decreased the internal reaction rate, and the presence of SOf ions caused the transformation of green rust I to green rust II. The increase of [$SO42−$]/[Cl⁻] enforced the formation of goethite (α-FeOOH) as a final product, whereas it reduced the formation of lepidocrocite (γ-FeOOH). The presence of akaganeite (ß-FeOOH), which formed in the chloride-containing aqueous medium, disappeared with the substitution of $SO42−$ ions in the solution.