Sorption of uranium(VI) compounds on fibrous anion exchanger surface from aqueous solutions

The effect of sorbent consumption and the kinetics and mechanism of sorption of uranium(VI) compounds on the surface of FIBAN A-6 fibrous anion exchanger from aqueous uranyl acetate solutions have been studied in the presence of sulfuric acid or sodium hydrocarbonate. The degree of sorption of uranium(VI) compounds by FIBAN A-6 anion exchanger has been found to be as high 97.0–99.5% at an interfacial contact time of 3–7 min and a sorbent consumption of 2–5 g/dm³. Diffusion and chemical kinetics models have been employed to show that the sorption kinetics of uranyl sulfate and carbonate complexes corresponds to the mixed diffusion mechanism and is described by a pseudo-second-order equation. The sorption isotherms of uranium(VI) compounds have the pattern of L-type isotherms according to the Giles classification and are satisfactorily described by the Langmuir, Freundlich, and Dubinin–Radushkevich equations. It has been found that, within 40 min, the sorbent may be regenerated by 65–82% with a 1 M NaHCO₃ solution.