PURPOSE: To produce an ion adsorbent which has high adsorption efficiency for heavy metal ions and is stable in high temp. water by forming and sticking a polymer or condensate of an oxyethylene chelating agent in the fine pores of activated carbon.

CONSTITUTION: Powder oxine is added at about 35% to activated carbon in a granular, disintegrated or powdery state, and these are mixed by shaking to adsorb the oxine. This is impregnated uniformly with an aq. formaldehyde soln. of an amt. equiv. to or larger than that of the oxine, after which it is treated with an alkali or acid to convert the oxine to methylol, thence it is heated for about 3 hours at about 150W200°C to evaporate the unreacted acid, formaldehyde, etc. and to form the polymer of the oxine in the fine pores of the active carbon. In the above-mentioned reaction, it is also effective to prepare the copolymer or condensate with the oxine by adding phenol, resorcinol beforehand to the activated carbon. It is also possible to use other oxine derivts. in lieu of part or the whole of the oxine.