Thermodynamic Functions and Kinetic Models for Methelyne Blue Adsorption on Corn Straw Pulp.

Document Type : Research Studies

Author

Mathematical and Physical Engineering Department, Faculty of Engineering, Mansoura University., Mansoura., Egypt.

Abstract

Methylene Blue (MB) in aqueous solutions was subjected to color removal by the adsorption technique onto corn straw pulp (CSP) as a biosorbent waste agricultural material. Results obtained indicate that the removal efficiency of Methylene Blue at 25°C exceeds 91% and that the adsorption process is highly pH-dependent. The optimum pH lies between 5 and 9. The amount of Methylene Blue adsorbed from the aqueous solution increases with the increase of the initial Methylene Blue concentration and temperature. Smaller adsorbent particles help in increasing the percentage removal of Methylene Blue. The results fit the BET model for adsorption of Methylene Blue on corn straws pulp, verify the assumption molecules could be adsorbed in more than one layer thick on the surface of the adsorbent. A comparison of kinetic models (pseudo first-order, the pseudo second order, Elovich and intraparticle diffusion kinetic models) at different conditions showed that the pseudo second-order kinetic model correlates the experimental data well. Van't Hoff equation was used to evaluate the thermodynamic parameters (AH, AS and AG) for the interpretation of the adsorption process. The values of the thermodynamic parameters indicate that all adsorption processes are endothermic, and this is in agreement with the increasing adsorption capacity with temperature. The process of removal of MB by Corn straw pulp is a spontaneous one. 

Main Subjects

MEJ- Mansoura Engineering Journal
Volume 34, Issue 4
December 2009
Pages 15-24

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