Multicomponent Dye Adsorption onto Carbon Using a Solid Diffusion Mass-Transfer Model

The adsorption of basic dyes onto activated carbon has been studied for single and multicomponent systems. Three single-component systems, one binary dye adsorption system, and one ternary dye adsorption system have been investigated. Equilibria and kinetic studies have been performed and the effects of varying initial dye concentration and carbon mass have been investigated during the kinetic experiments. Prediction of experimental equilibrium data has been performed by use of the ideal adsorbed solute theory, the extended Redlich-Peterson isotherm, and a modified extended Redlich-Peterson isotherm. The predictions from the modified extended Redlich-Peterson isotherm, incorporating an interaction factor, correlated experimental data well and also provided a reasonably simple format that could be incorporated into a kinetic model. The kinetic model developed for agitated batch adsorbers is based on the film solid diffusion model coupled with the modified extended Redlich-Peterson isotherm. Kinetic data for the binary and ternary systems are correlated with experimental data for up to 3 h over a wide range of dye concentrations and carbon masses.