Influence of operating conditions on methylene blue uptake by a smectite rich clay fraction

Effect of contact time, solute concentration, exchangeable cations, temperature, pH and ionic strength on methylene blue (MB) adsorption in aqueous solutions by a smectite-rich clay-sized fraction was investigated by UV–visible spectroscopy. The adsorption kinetic obeyed a pseudo-first order reaction (kc = (1.7 ± 0.3) × 10− 2 min− 1), and was chiefly controlled by the dye diffusion within clay particles. MB adsorption depended on the nature of exchangeable cations, pH and ionic strength but was almost insensitive to temperature changes between 15 and 35 °C.