Several active carbons derived from different precursors and oxidized by different techniques have been characterized by N-2 porosimetry and various titration methods. The adsorption of Cu2+, Ni2+, CO2+' Zn2+ and Mn2+ from aqueous solutions was studied using these carbons and carboxylic resin Purolite C104. The affinity series Mn2+ < CO2+ < Ni2+ < Cu2+ > Zn2+ established in adsorption experiments coincides with the Irving-Williams order and is independent of the method and extent of adsorbent oxidation, carbon precursor, porous structure, and type of adsorbent. Enhanced selectivity of adsorbents towards Cu2+ is related to the electronic structure of this ion.