Local equilibrium sorption transport model

The first transport model (local equilibrium sorption) is formulated by assuming that local equilibrium exists along the column. No immobile-water phase is present. The water velocity is... 

The third and fourth models are based on the assumption of an immobile-water phase. This phase can be caused by the existence of crevices or pits on the grain surfaces and by dead-end pores created by tight packing of the grains. In this article, we did not consider an immobile-water film that could cover entire grain surfaces. Diffusion of Mo(VI) into the immobile-water phase retards transport because of the capacitance of this phase and also provides a rate-limiting step for sorption on the solid matrix adjacent to the immobile-water phase. For these models, transport of Mo(VI) from the flowing phase can occur by sorption to the solid phase or by diffusion to the immobile-water phase which then is followed by sorption to the solid phase. The sorption from either phase is assumed to be at local equilibrium with the adjacent fluid phase. An additional balance equation for the solid phase adjacent to the immobile-water phase is as follows ... 

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