Shrinking Core Model in characterizing aqueous phase dye adsorption

The fluid–solid non-catalytic reactive system is characterized by the widely accepted Shrinking Core Model. In the present investigation the same model has been applied to characterize the adsorption of Methylene Blue (MB) and Congo Red (CR) dyes in the aqueous phase onto Rice Husk Ash (RHA). The effective pore diffusivities of different dye molecules in RHA are determined by a suitable global optimization technique. The depth of penetration has also been estimated for various initial concentrations of dyes. The values predicted by the model are compared with experimental concentration profiles at different initial concentrations of these dyes. The theory–experiment comparison has revealed that predicted values are in excellent agreement with the experimental values.