Langmuir isotherm models applied to the multicomponent sorption of acid dyes from effluent onto activated carbon

The adsorption of three acidic dyes, Acid Blue 80 (AB80), Acid Red 114 (AR114), and Acid Yellow 117 (AY117) onto activated carbon, Filtrasorb 400, has been studied. Three single-component and three binary, AB80 + AR114, AB80 + AY117, and AR114 + AY117, isotherms were determined. Four models for predicting the multicomponent equilibrium sorption isotherms have been compared in order to determine which is the best; fit model to predict or correlate binary adsorption data. These were an extended Langmuir isotherm, a simplified model based on single-component equilibrium factors, a modified extended Langmuir isotherm with a constant interaction factor, and a modified extended Langmuir isotherm incorporating a surface coverage dependent interaction factor.