STUDY OF THE POSSIBILITY OF IRON(II) EXTRACTION USING PHENOL-TYPE OLIGOMERIC EXTRACTANTS

This paper investigates the liquid–liquid extraction of iron(II) ions using oligomeric phenolic extractants synthesized from phenol-formaldehyde resins. The effects of the main physicochemical parameters of the extraction system—including the pH of the aqueous phase, metal-ion concentration, extractant content, and duration of interfacial contact—on the efficiency of Fe(II) extraction were studied. Particular attention was paid to establishing the relationship between the structural features of oligomeric phenolic compounds and their extraction characteristics. It is shown that the use of oligomeric extractants may potentially improve the selectivity of Fe(II) ion extraction and increase the distribution coefficient compared with monomeric phenolic compounds. The observed patterns may be attributable to the presence of several functional groups involved in interactions with metal ions, as well as to the spatial organization of oligomer molecules. Based on the presumed patterns of interaction between the extractant and iron(II) ions, the possibility of complexation accompanied by the formation of chelate-like structures that promote metal retention in the organic phase is considered. The composition and structure of the resulting complexes require additional physicochemical confirmation using appropriate analytical methods.