Adsorption of Ions by Oxide Powders

The structure of the electric double layer at a solid/solution interface (S.F. Estefan, M.A. Malati, Tenside Detergents, 11(1974)205). 

A Potential determining layer B Stem layer C Dilfuae Gouy layer A Inner Helmhoflz plane B Outer Helmholtz plane C Shear plane Potential - determining Ion 0 Cation immobile (hydrated) Anion (hydrated) 

The Langmuir adsorption Isotherm (W.A. Adamson, Physical Chemistry of Surfaces, 3 edn., Interscience, New York, 1976) 

Adsorption equilibrium is reached when the amount of adsorbrate taken up by the solid adsorbent does not change with time. The amount adsorbed g of solute, X, is calculated from the difference between the initial and equilibrium concentration C. By varying the initial concentration and determining X, Langmuir assumed that X reaches a limiting value, X , presumably when a monomolecular layer is formed on the surface. The variation of X with C, known as the Langmuir adsorption isotherm can be represented in a linear form by  

In many industrial laboratories and in numerous institutions, analysis of solids, to determine the percentages of C, H, N etc., is carried out routinely by trained technicians. These analyses are also valuable for complex compounds with organic ligands or organometallics. Such analyses, though not carried out by students, will help them to characterise their prepared products. 

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