Thermodynamics Research Today is a free monthly online journal that collates and summarizes the latest research about Thermodynamics, including details on enthalpy, entropy, energy transitions.

Equilibrium, kinetic and thermodynamic studies of adsorption of fluoride onto plaster of Paris.

Gopal V, Elango KP

Tamil Nadu Water Supply and Drainage Board, District Water Testing Laboratory, Theni 625 531, India.

Batch sorption system using plaster of Paris as an adsorbent was investigated to remove fluoride ions from aqueous solutions. The system variables studied include initial concentration of the sorbate, agitation time, adsorbent dose, pH, co-ions and temperature. The experimental data fitted well to the Freundlich and Langmuir isotherms. Thermodynamic parameters such as DeltaH degrees , DeltaS degrees and DeltaG degrees were calculated indicating that the adsorption was a spontaneous and exothermic. Kinetic studies reveal that the adsorption is first order. A mechanism involving three stages (external surface adsorption, intraparticle diffusion and final equilibrium) has been proposed for the adsorption of F(-) onto plaster of Paris. XRD patterns of the adsorbent were recorded to get a better in sight into the mechanism of adsorption process.

Published 20 February 2007 in J Hazard Mater, 141(1): 98-105.
Full-text of this article is available online (may require subscription).

© 2005-2008 Thermodynamics Research Today. All Rights Reserved.