Extended liquid -solid BET isotherm

The extended liquid-solid BET isotherm describes well the adsorption behavior corresponding to types II or III isotherms of the van der Waals classification of isotherms (see Figure 3.1). Its expression parallels that of the BET isotherm model which is often applied in gas-solid equiUbtia [3]. It assiunes the same molecular description the solute molecules can adsorb from the solution onto either the bare surface of the adsorbent or a layer of solute already adsorbed. The equation of the model is derived from kinetic adsorption-desorption relationships, assuming first order kinetics [10,85]. The expression obtained after a rather lengthy derivation is... 

Figure 3.27 Adsorption data of butylbenzene measured by FA on Cig-Chromolith, with methanobwater, 80/20 (v/v) at 296 K. A) Plot of the isotherm data and best extended liquid-solid BET isotherm. B) Plot of the experimental isotherm chord. Note the strictly anti-langmuirianbehavior (b/ > bg/2).

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