A theoretical analysis was developed to predict the apparent viscosity of a non-Newtonian fluid in a rotating packed bed. It is based on laminar liquid film flow on a rotating disk with the assumption of the randomly inclined surfaces in the rotating packed bed. In addition, experiments of deoxygenation were performed in glycerol solutions and CMC solutions, which are Newtonian and shear-thinning fluids, respectively. It is shown that mass transfer coefficients decreased with increasing viscosity, while the centrifugal force still revealed effective in enhancing mass transfer in viscous media. A correlation for mass transfer coefficient was proposed and valid for both the Newtonian and non-Newtonian fluids. Compared with a packed column, the influence of mass transfer coefficients by liquid viscosity was less in a rotating packed bed.

The adsorption kinetics of a surfactant is used to apply the equilibrium surface tension data γ(C) for the determination of the adsorption isotherm and then to apply the dynamic surface tension γ(t) on determining the controlling mechanism, the diffusivity, and/or the sorption rate constants. A concept for surfactants lacking low surface pressure data has been proposed (Hsu et al. Langmuir 1997, 13, 6204; 1999, 15, 1952):  using only a limited range of equilibrium surface tension data to determine the adsorption isotherm can cause a mistake on determining the adsorption mechanism and diffusion coefficient. In this work, the above concept is extended:  even though an isotherm describes the γ(C) data well, it may describe the dynamic surface tension data incorrectly. An incorrect controlling mechanism and/or a diffusion coefficient with a significant error may result if only the γ(C) data are applied on determining the adsorption isotherm and model parameters. A second set of equilibrium data, equation of state γ(Γ), is useful and necessary for studying the adsorption kinetics. A theoretical simulation and two examples (for surfactants with either cooperative or anticooperative adsorption) are presented in this article to illustrate this concept.

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