A novel method for the synthesis of fibrous adsorbents containing amidoxime

The fibrous adsorbents were prepared by radiation induced graft polymerization of aclyronitrile onto the fiber of tetra-fluoroethylene-ethylene copolymer followed by a chemical conversion of cyano group into amidoxime group. In liquid phase grafting, a homogeneous grafting occurs throughout the whole substrate. In the vapor phase grafting, on the other hand, the grafting is located at the surface area of the substrate. Thus, the distribution of functional groups in the polymer matrix was well controlled by selecting appropriate experimental conditions. The adsorption of metal ions with the fibrous amidoxime type adsorbents obtained by the surface grafting was more rapid than with the adsorbents obtained by homogeneous grafting. It was also clarified that the adsorptive activity was greatly improved by the introduction of hydrophilic groups. The grafting of acrylic acid was the most effective. The stability constant of Cu2+ complex(K) and the saturated amount of Cu ions(As) was 5400 1/mol and 0.55 mol/unit mol for the fibrous adsorbents containing both amidoxime groups and carboxyl groups. (author)