SORPTION OF FLUORIDE IONS BY IRON OXYHYDRATE FIXED ON THE CARRIERS. Part 1. Organic carriers

The article considers possibility of using inorganic sorbent – iron oxyhydrate (IOH) – to remove F– ions from process solutions of zinc production. The method of IOH synthesis is chosen. The results of scanning electron microscopy and X-ray phase analysis are presented. The principal possibility of using ion-exchange resins as IOH-modified carriers is considered. The paper studies active substance formation on anion and cation exchange resins. It is shown that the most durable composite sorbents are obtained using strongly acidic cation exchange resins with SO3– groups. A method for introducing IOH into the structure of carrier materials and obtaining composite sorbents is described. The KU-2×8 strongly acidic cation exchanger is recommended as a composite base. Cation exchangers saturated with iron were held in a sodium chloride solution with a concentration of 2,5 g/dm3 for 24 hours at 85 °C to ensure formation of β-modification IOH crystals distributed over the ion exchanger grain volume. Anion exchangers were held in an iron(III) sulfate solution with added sodium chloride for 24 hours at 85 °C. At the same time, iron oxyhydrate films formed on the surface of sorbent grains were observed. Fluorine sorption was carried out in a static mode from a standardized test solution with a concentration of F– = 100 mg/dm3 at 60 °C. Sorption on the AB-17×8 anionite was carried out at 20 °C. Absorbed fluorine was desorbed by the NaOH (0,1 M) solution at 60 °C for 2 hours. The synthesized KU-2×8-IOH composite sorbent has a fluorine capacity of 0,7–1,1 mg/g, and can be regenerated with resulting easily utilizable fluorine-containing eluate.