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

Subject Areas : Journal of the Iranian Chemical Research

Ghazaleh Koutchakzadeh ¹ , Zohreh Derikvand ²

1 - Department of Chemistry, Korram Abad Branch, Islamic Azad University, Korram Abad, Iran
2 - Department of Chemistry, Korram Abad Branch, Islamic Azad University, Korram Abad, Iran

Received: 2011-08-10 Accepted : 2012-03-10 Published : 2012-03-20

Keywords: MCM-41, Safranine, Langmuir isotherm, Freundlich isotherm, Equilibrium Adsorption,

Abstract :

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

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