Freundlich-Ostwald-Boedecker FOB

Today this AI most often is known as Freundlich-isotherm although it is due to the three authors mentioned [7.34]. It is a truncated Taylor-series expansion of the mass adsorbed (m) in powers of an often non-integer power (a 0) of the sorptive gas pressure (p)  

The limiting cases H = 0 and H — oo are realized - for example - for water vapor adsorption on activated carbon (AC) and hydrophilic zeolites 

The exponents (Ui, i = 1...N) are related to energetic inhomogeneities and also to the fractal nature of the surface of the sorbent material [7.15, 7.35-7.37]. Numerical values are often in the range 0.2 Uj 1. 

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