Adsorption and desorption of metal ions by systems based on cellulose derivatives that contain amino acid residues.

Abstract

A reactive cellulose intermediate having free isocyanate groups (isocyanate cellulose) was prepared by the treatment of cellulose with 2, 4-tolylene diisocyanate (2, 4-TDI). The reactions of the isocyanate cellulose with amino acids in organic solvents gave cellulose derivatives containing amino acid residues. The amounts of amino acids bound to the isocyanate cellulose through the urea linkage were 0.360_??_0.747mmol/g.The adsorption and desorption of metal ions by systems based on the cellulose derivatives were investigated. The cellulose derivatives could adsorb various kinds of metal ions from aqueous solution with relatively high adsorption values for copper (II) and iron (III) than zinc (II), cadmium (II), chromium (III) and mercury (II) ions. The cellulose derivative containing cysteine was especially effective for the adsorption of mercury (II) ion with the distribution coefficient, [Kd]=1.63×103.The desorption of copper (II), zinc (II) and cadmium (II) ions from the derivatives were effected completely with 2N HCl and that of iron (III), with 4N HCl. These derivatives could readsorb metal ions.