Interpretation of Transition Metal Sorption Behavior by Oxidized Active Carbons and Other Adsorbents

Abstract

Several active carbons derived from different precursors and oxidized by different techniques have been characterized by N₂ 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.

Keywords:

• Oxidized carbon
• Transition metal sorption
• Selectivity
• The Irving–Williams series
• Surface oxygen complexes