Theory and Background

The reactions considered in this review include at least one liquid phase. When a liquid is in contact with another phase, even in a system which is stirred, transport between the two phases is not instantaneous. Close to the interface, in the receiving phase, there is a thin region referred to as the diffusion film, which behaves as if it is unstirred. Transport across this film is by diffusion only. Consider a pure material (liquid or gas) in contact with a liquid in which it dissolves to some extent (Fig. 5.1). It is assumed that equilibrium is maintained across the interface, so that the concentration of the solute adjacent to the interface in the receiving phase is always at saturation. 

The film thickness is not directly accessible, and the term D/S, which has units cm s 1, is referred to as the mass transfer coefficient, ki. In solid/liquid and liquid/liquid systems, values of kL are typically 1-2 x 10 3 cm s-1 with values of D typically 5 x 10 6 to 2 x 10-5 cm2 s 1, corresponding to diffusion film thicknesses of 50-100 pm and film diffusion times of around 5 seconds. 

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Ornstein, L, Disc Electrophoresis—I Background and Theory, Annals of the New York Academy of Sciences 121, 321, 1969. 

Godbee, H. W. and Joy, D. S., "Assessment of the Loss of Radioactive Isotopes from Waste Solids to the Environment. Part I Background and Theory," Oak Ridge National Laboratory, Oak Ridge, Tennessee, 1974. 

The separation techniques described here are those of most interest to analytical chemistry. The background and theory of separation by the single-stage processes of precipitation and electrodeposition are discussed in Chapters 7 and 14. In this chapter some general introduction to separations is presented along with a brief background for several separation processes. 

Bertini I, Martini G and Luchinat C 1994 Relaxation, background, and theory Handbook of Electron Spin Resonance (ed C Poole and H Farach (New York American Institute of Physics) ch 3, pp 51-77... 

ULTRAHIGH VOLTAGE CAPILLARY ELECTROPHORESIS 24.2.1 Background AND Theory... 

The mathematical background and theory of the computational methods is beyond the scope of this chapter and can be found elsewhere [Young, 2001 Ramachandran et al, 2008],... 

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