Characterization of the effects of silicon on the formation of goethite

Goethite samples were synthesised with different sodium silicate concentrations (0, 10−5, 10−4, 10−3 and 10−2 M) in the initial aqueous solution. X-ray diffraction (XRD), Mössbauer spectrometry, inductively coupled plasma mass spectrometry (ICP-MS) and transmission electron microscopy (TEM) were used to investigate the influence of Si content on the formation and physical characteristics of goethite. Mössbauer spectroscopy and TEM results demonstrate that the particle size changes as the sodium silicate content increases. XRD results (lattice parameters, line width and mean coherence length values) do not show any indication that Si species would substitute for Fe in the goethite structure.

Research highlights
► Goethites synthesised in presence of different concentrations of Si.
► No evidence of Si substitution into goethite structure.
► Inhibition of particle growth due to increasing Si content via solution.
► Study of Si in goethite can be considered in corrosion of weathering steels.