Research Article

Separation and Determination of Fe(III) and Fe(II) in Natural and Waste Waters Using Silica Gel Sequentially Modified with Polyhexamethylene Guanidine and Tiron

Figure 7

EPR spectra of Fe(III) complexes formed on the surface of SiO2-PHMG-Тiron sorbent during the sorption of Fe(III) (1) and Fe(II) (2) and Fe(III) complexes with Tiron in aqueous solution after interaction between Fe(III) (3) or Fe(II) (4) and Tiron (рН: 3.0 (1), 6.2 (2), and 8.0 (3, 4), 0.200 g of the sorbent (1, 2),and = 20 μg per 0.200 g of the sorbent (1, 2), 0.36 mМ (3, 4); μmol g−1 (1, 2); 1.6 mМ (3, 4)).