Phase behavior of Eu(III) in fulvic acid-Fe(III)−H20 system at pH 1-9

The method was developed allowing quantitative extraction of fulvic acids from soil samples in the form close to native. Formation of gel-like and soluble forms of iron(III) fulvates in the systems containing equivalent amounts of iron(III) and fulvic acid was studied within pH range 1–9. The molecular structure of fulvates and the mechanism of transformation of gel to soluble forms was analyzed by IR spectroscopy. Distribution of microamounts of europium between gel-like iron fulvates and their solutions was studied. The correlation between phase distribution of europium and solubilization of iron(III) fulvates was analyzed.