Studies on Thermodynamics of Stoichiometric Displacement Model for Adsorption of Solute from Liquid-Solid System
CHEN Yu-Yin, GENG Xin-Du (Department of Chemistry, Northwest University, Xi'an, 710069)
Free energy change of stoichiometric displacement process for adsorption(SDM-A) of solute in a liquid-solid system was investigated. An expression which elucidates the contributions of each solute, solvent and adsorbent in the system to Gibbs free energy change was derived and the physical meaning of each parameter of the expression was also explained. Gibbs free energy change of adsorption for solute determined with traditional method can be divided into two independent fractions relating to the adsorption of solute and to the desorption of solvent, respectively. A linear relationship between two linear parameters BBBBBBBa and q/Z of the SDM-A and the reciprocal of absolute temperature was derived. And, each of the changes in both enthalpy and entropy of the SDM-A of solute can also be separately divided into two independent fractions. The derived equations were tested with experimental data in literatures and a conformable result between the both was obtained.