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

Abstract

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