Sorption plate theory

Kotdawala et al.415 develop a mean-field perturbation theory for the study of polar molecules in slit pores and validate their model by comparison with MC simulations. Their theory incorporates the electrostatic interactions, and allows prediction of adsorption isotherms for molecules confined between two parallel plates. The model is used to study sorption of water molecules, and results of this model are compared with others in the literature. 

This single-step process could be thought of as a single plate or single sorption step (Fig. 4.3). The word plate comes from the early theory used in chromatography to describe sorption and refers to distillation columns that contain plates. 

The theory for sorption onto the fibers has been described in a study by Louch and co-workers (1992). According to the authors, SPME does not exhaustively extract the solute onto the fiber in most cases because there is only one theoretical plate or one sorption step. Rather, an equilibrium is developed between the aqueous concentration and the sorbed concentration. The number of moles of analyte on the fiber, n, is linearly related to the concentration in the aqueous phase by the following equation ... 

Let us consider again a sorption system consisting on a sorbent-sorbate phase and a sorptive gas located between the plates or cylinders of a capacitor, Fig. 6.8. This system is an electric network which for small applied voltages (U(t)) can be interpreted as a Linear Passive System (LPS). That is a stimulus (U(t)) applied to the system creates a response, the electric current I(t), which is linearly related to U(t). However it may exhibit a phase shift and also lead to energy dissipation, i. e. Ohmian heat which, as a consequence of the Second Law of Thermodynamics at finite ambient temperature, never can completely be reverted again to electric energy. Linear Passive Systems can be found quite frequently in Physics. A mathematical theory of such systems has been developed by H. Kdnig and J. Meixner in the 1960 s, [6.27] and later on extended and applied to various stochastic processes, i. e. statistical physics by J. U. Keller, [6.28]. 

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