Complexation of Fe(III) with water-soluble oxidized starch

In this work, we have studied the use of the oxidized starch as a water-soluble complexing agent for Fe(III) in alkaline conditions. Fe(III) was completely soluble in alkaline solutions with a 0.65:1 molar ratio of the oxidized starch-to-Fe(III) ion. The oxidized starch could also solubilize precipitated Fe(OH)3 under alkaline conditions. FT-IR measurements of the oxidized starchFe(III) complex indicated that there was a direct coordination between anionic ligands (O and COO) of starch and the Fe(III) ion. Additionally, hydrogen bonding occurred between hydroxyl groups of oxidized starch and Fe(III) which decreased as pH increased. It was also detected that the binding mechanism did change according to the pH of the Fe(III) solution of the oxidized starch addition.