The Isosteric Heat of Adsorption of Sr 2+,Ce 3+,Sm 3+,Gd 3+,Th 4+ and UO 2 2+ Ions on Activated Charcoal

Abstract

The values of the isosteric heat of adsorption (q_st) of Sr²⁺, Ce³⁺, Sm³⁺, Gd³⁺, Th⁴⁺ and UO₂²⁺ ions on activated charcoal have been calculated at different surface coverages and temperatures by applying the Clausius–Clapeyron equation. The variation of q_st with surface coverage indicates the heterogeneous nature with varying activities of the activated charcoal surface. The behaviour of q_st values with temperature suggests that two types of adsorption processes occur simultaneously; one with a small activation energy and the other with a large activation energy. A large increase in the q_st values indicates that increasing temperature changes the physical adsorption process to chemisorption.