Abstract: The present invention is to provide a novel adsorbent which is low in cost, has versatility and has high adsorption ability. Specifically, the present invention is to provide an adsorbent containing a metal salt of a cyanometallic acid obtained by a reaction of a salt of a cyanometallic acid and a compound containing a metal element, wherein the reaction is carried out using the compound containing a metal element in an amount of less than 100 mol % of the theoretical amount relative to 1 mol of the salt of a cyanometallic acid, a method of producing the same, and a method for removing harmful ions from water using such an adsorbent.

Abstract: The present invention is to provide a novel adsorbent which is low in cost, has versatility and high adsorption ability. Specifically, the present invention is to provide an adsorbent of a specific metal element containing a metal salt of a cyanometallic acid, a method for producing the same, and a method for removing the ion of the element that is the target of adsorption using such an adsorbent.