Ostwald-de Izaguirre equation

The adsorption of binary systems is described by the Ostwald-de Izaguirre equation, which establishes a relationship between the specific reduced adsorption excess amount (nf" ) and the material amount in the interfacial layer ( " = n + n ) [40-46] ... 

When solid particles are immersed in liquid medium, solid-liquid interfacial interactions will cause the formation of an adsorption layer on their surface. The material content of the adsorption layer is the adsorption capacity of the solid adsorbent, which may be determined in binary hquid mixtures if the so-called adsorption excess isotherm is known. Due to adsorption, the initial composition of the hquid mixture, x , changes to the equilibrium concentration Xj, where n = n +rf2, the mass content of the interfacial phase (e.g., mmol/g). This change, Xj — Xj = Axj, can be determined by simple analytical methods. The relationship between the reduced adsorption excess amount calculated from the change in concentration, = n°(x — xj), and the material content of the interfacial layer is given by the Ostwald-de Izaguirre equation [1-5]. In the case of purely physical adsorption of binary mixtures, the material content of the adsorption layer ( = — n) for component 1 is... 

The Ostwald-de Izaguirre equation is obtained free from any assiunprion from the mass balance ... 

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