ADSORBENT AND PROCESS FOR PRODUCING THE SAME

An arsenic adsorbent which is superior in the ability to adsorb boron, arsenic, and fluorine to conventional adsorbents, effectively functions even when the concentrations of these are low, and has a long life. Maintenance of the adsorbent is easy, and adsorbent or resin components do not dissolve away. The adsorbent for boron, arsenic, and fluorine is an arsenic adsorbent comprising a hydroxide and/or hydrous oxide of a rare earth element and a water-resistant polymer resin with which the surface of the hydroxide and/or hydrous oxide is coated, and characterized in that the hydroxide and/or hydrous oxide has a central void and micropores surrounding the central void and that the polymer resin with which the surface of the hydroxide and/or hydrous oxide is coated constitutes a porous skin layer.