ADSORPTION BEHAVIOR OF Cu(II) ON SILK FIBROIN FIBERS

Abstract

Adsorption of Cu(II) on the silk fibroin fibers was investigated in terms of the initial adsorption rate, the equilibrium state and the adsorption of Cu(II) on the silk fibroin fibers modified with acetic anhydride or dehydrate methanol. The following results were obtained:
1) The initial adsorption rates were somewhat different by external anions. The order of the adsorption rates were The variation of the initial adsorption rates with the Cu(II) concentrations was obtained a straight line and its line was drawn through the origin at 80°C treatment. Consequently, the diffusion of the Cu(II) into fiber become rate determing stage. But a little. surface adsorption was recognized at 40°C treatment.
2) The apparent activation energy of diffusion of initial adsorption was obtained the values of 5_??_7 Kcal/mol.
3) Adsorption isotherms were shown Langmuir type. From our examined results, it was suggested that the adsorption sites of the Cu(II) were the carboxyl end groups of the silk fibroin fiber in pH 3.75, but their sites was both the carboxyl and amino end groups of its fiber in pH 4.53
4) The combine ratio between the silk fibroin fiber's end groups and the Cu(II) was recognized NH₂2 I Cu(II) and COOH 1:1 Cu(II) in pH 4.53 from the results of Cu(II) adsorption on the modified silk fibroin fibers.