Sorption and desorption of Fe(III) on natural and chemically modified zeolite

The Fe(III) uptake from aqueous solutions by natural and chemically modified zeolites was investigated using a gradual radioexchange method and AAS technique. The leachability of Fe(III) from loaded zeolites was studied too. The Fe-uptake reached the value of 60 mg·g⁻¹ for the zeolite chemically treated with 6 mol·l⁻¹ solution of NaOH and it is more than twelve times higher than that of the raw zeolite. The leachability of the loaded zeolite samples in water and alkaline solution was up 5%. The leachability of the same zeolites in acid solution depended on the concentration of modifying solution. The leachability at pH=2.6 in the range 2–20% at pH=1.9 was many times higher. The results of the radioexchange and AAS methods were compared.