Amidoxime-group-containg adsorbents for metal ions synthesized by radiation-induced grafting

Amidoxime‐group‐containing fibrous adsorbents for metal ions were synthesized by radiation‐induced grafting of acrylonitrile followed by amidoximation of cyano groups with hydroxylamine. The degree of amidoximation and the distribution of amidoxime groups in the fiber were follwed by means of electron probe X‐ray microanalysis. The efficiency of adsorbing metal ions was increased by alkaline treatment of the adsorbent at high temperature for a short period before use. The order of adsorption for various bivalent metal ions was Hg > Cu > Ni > Co > Cd. From the distribution pattern of metal ions in the fibrous adsorbent, the adsorption was found to be controlled by the diffusion of the solution containing metal ions inside the adsorbent. It was found that confining amidoxime groups superficially and making short chain length of grafts were effective to obtain a high degree of adsorption.