Isothermal and thermodynamic studies of the adsorption of safranine on MCM-41

The uses of MCM-41 as adsorbent have been studied as an alternative substitution of activated carbon for the removal dyes. This adsorbent was prepared at laboratory by authors. Adsorption of safranine on MCM-41 was studied to examine adsorption thermodynamics. In this study was investigated the effect of procces parameters like pH, initial dye concentration, temperature and adsorbent mass. MCM-41, as adsorbent, is characterized by high surface area and high pore volume to adsorbed dye very well. In this study, both Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. Langmuir model being has found to provide the best fit of experimental data. Results of thermodynamic evaluation indicated that adsorption reaction was spontaneous because Gibs energy was negative. This reaction was exothermic with negative enthalpy and reducing entropy.