Selective Sorbents Based on Silica Modified with 1,10-Phenanthroline Derivatives for FE(II) and FE(III) Ions

A new sorbent for the extraction of metal ions has been obtained by immobilization of 1,10-phenanthroline derivatives on the silica surface, which significantly exceeds analogues obtained by adsorption immobilization of 1,10-phenanthroline on the surface in terms of sorption properties. The developed sorbent selectively removes Fe(II) at pH = 1.0; at pH > 4, on the contrary, preferentially adsorbs Fe(III). The sorption kinetic of Fe(II) and Fe(III) ions is described by a pseudo-second-order equation corresponding to their chemisorption on the sorbent surface. The distribution coefficients of Fe(II) ions on the obtained sorbent reach to 10⁴-10⁵ cm³/g, which reveal the prospects of its using for the selective removal of Fe(II) ions from aqueous solutions in the presence of macrocomponents of natural waters, as well as for the determination of Fe(II) and Fe(III) ions in environmental and drinking waters at the maximum permissible level and below.