Adsorption of cationic dyes from aqueous solutions by sepiolite

Batch sorption experiments were carried out to remove the cationic dyes, methyl violet (MV) and methylene blue (MB), from its aqueous solutions using sepiolite as an adsorbent. Operating variables studied were pH, ionic strength and temperature. Adsorption process was attained to the equilibrium within 3 h. The adsorbed amount of MV and MB dyes on sepiolite increased with increasing pH, ionic strength and temperature. The experimental data were analysed by Langmuir and Freundlich isotherms, and found that the isotherm data were reasonably well correlated by Langmuir isotherm. Furthermore, for the removal of MV and MB dyes, a batch reactor was designed. Adsorption measurements showed that the process was very fast and physical in nature.