The goal of the present paper was to elucidate if-and how-the parameters of the Brouers-Sotolongo fractal (BSf) (n,α) kinetic model (α and τC) on the one hand, and of the generalised Brouers-Sotolongo (GBS) isotherm model (a and b) on the other hand, are correlated with adsorption pH and temperature. For that purpose, adsorption of aqueous solutions of two common dyes, methylene blue (MB) and methyl orange (MO) was carried out on four activated carbons (ACs) at three temperatures (25, 35 and 50 °C) and three pH (2.5, 5 and 8). Adsorption kinetics and isotherms were measured, and the corresponding curves were best fitted with specific forms of the aforementioned models, and corresponding to equations known as BSf (1,α) kinetic and Brouers-Gaspard isotherm models. Correlations between all model parameters and adsorption conditions were found, bringing some information about the adsorbate-adsorbent interaction.
Keywords: Activated carbon; Adsorption; Brouers–Gaspard isotherm; Dyes; Fractal kinetics; Heterogeneous surface.