Synthesis and Chemical Stability Studies of Sodium Ferrate(VI) Solution

Abstract

Sodium ferrate solution was prepared by the wet oxidation process using liquid FeCl3 with NaOCl in a strong alkaline solution. The reference and the product were characterized using UV-visible, XRD and FTIR. The maximum concentration of Na2FeO4(VI) solution was 12.4 g/L (as FeO4 2-). Its stability was studied by recording the absorbances of several ferrate solutions at 505 nm on daily basis for a period of one month. The average rates at pH 12 were 3.19 × 10-11 M s-1 for K2FeO4 and 1.09 × 10-11 M s-1 for Na2FeO4. These average rates of degradation indicate that ferrate can last longer without conserving the ferrate solutions using different buffer solutions or phosphates. The peaks obtained around 700, 769 and 879 cm-1 using FTIR confirmed the presence of Fe-O bond in the crystals, which is Na2FeO4 (VI). XRD patterns showed an isomorphism between the diffractograms of Na2FeO4 and K2FeO4.