Absorption desorption, concentration profiles

This expression will predict the movement of a solute whose adsorption is in equilibrium with the surrounding strata. This equilibrium chromatographic motion will result in the migration of a band of activity whose concentration profile is gaussian and whose deviation will be a function of the hydrodynamic dispersion, T (due to statistical variations in path length) and absorptive dispersion T (due to statistical variations in the absorption and desorption process). While these dispersions are interactive and do not sum in a simple fashion they both depend on path length. 

Figure 2-4 Typical concentration profiles of instantaneous reaction between the gas A and the reactant C, based on film theory, ids Diffusion controlled - slow reaction, (fcl kinetically controlled-slow reaction, (c) gas-film-controlled desorption - fast reaction, 0 liquid-film-controlled desorption-fast reaction, (e) liquid-film-controlled absorption -instantaneous reaction between A and C, (/) gas-film-controlled absorption-instantaneous reaction between A and C, (g) concentration profiles for A, B, and C for instantaneous reaction between A and C-both gas- and liquid-phase resistances are comparable.1 2...

While in the absence of chemical reactions the concentration profile has a zero curvature, Eq.l7 shows that the curvature will be non-zero when reactions take place. In particular, the curvatu re will be positive in absorption and negative in desorption, but in both cases the effect of the chemical reaction is to make the concentration gradient at the interface steeper that it would be in the absence of chemical reactions. Hence, one expects an enhaji cement factor larger than unity. 

Just as in the case of absorption accompanied by a reaction of a gas in liquid, desorption accompanied by a gas-licjuid reaction IA + zC (non volatile) B (volatile) may conform to various mecdianisms. Results have been summarized and the concentration profiles have been schanatically depicted on eaodi side of the interfacial area (x = 0) by Shah and Sharma (3) in Figure 1 in the case in vhich a gas A dissolves into the Tiquid phase and then reacts irreversibly with a non-volatile species C that is present in the liquid phase to give the volatile species B according to the reaction... 

Figure L Typical concentration profiles for simultaneous absorption/ desorption. Typical concentration profiles for instantaneous reaction between the gas A and reactant C—file theory.

Similar kinetics of absorption and of desorption are obtained when these two rubber compounds are cured with either 90% or 96% for the state of cure. The profiles of concentration developed through the thickness of the sheets lead to some observations the rate of evaporation of the liquid is finite a decrease in the thickness of the sheets is observed during this stage. The time necessary for the stage of desorption is longer than that of absorption, resulting from the rather low rate of evaporation of toluene. 

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