Energy, Enthalpy, and Isosteric Heat of Adsorption of Phosphate on Hydrous Al Oxide

✍ Scribed by A.K. Helmy; E.A. Ferreiro; S.G. de Bussetti

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 95 KB
• Volume: 183
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1996.0526

✦ Synopsis

pressure. Thus in the surface layer, the partial free energy The use of surface pressure as a variable to describe adsorption of the molecules G a can be written as made possible the evaluation of the thermodynamic equilibrium constant, the standard free energy, and enthalpy of the adsorption

reaction of phosphate on hydrous Al oxide. The values obtained at 299ЊK are as follows: K Å 1.567 1 10 02 cm, DGЊ Å 10.33 kJ mol 01 , and DHЊ Å 25.11 kJ mol 01 . The magnitude of the values where GЊ a is the partial free energy at unit surface pressure, as well as the values of the isosteric heat of the reaction (023.7 viz., in the standard state. In the gas phase the partial free to 029.4 kJ mol 01 ) are of the order expected for a ligand exchange energy of the ideal gas G g can be expressed as reaction on an hydroxylated heterogeneous surface.