Sorption isotherms and characteristics of U(VI) ion onto composite adsorbent

Abstract

The adsorption of U(VI) from aqueous solutions onto composite adsorbent (Gumalgin Cromatic) has been studied using a batch adsorber. The parameters that affect the U(VI) sorption, such as contact time, solution pH, initial U(VI) concentration, and temperature, have been investigated and optimized conditions determined. The adsorption patterns of metal ions on composite adsorbent followed the Langmuir, Freundlich and Dubinin-Radushkevich isotherms. The Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) models have been applied and the data correlate well with Langmuir model and that the sorption is physical in nature (the sorption energy Eads 1/4 14.45 kJ/mol). Thermodynamic parameters (?H° ads = -129.55 kJ/mol, ?S° ads = -357 J/mol K, ?G° ads (298.15 K) = -23.11 kJ/mol) showed the exothermic heat of adsorption and the feasibility of the process. The results suggested that the composite adsorbent is suitable as a sorbent material for recovery and biosorption/adsorption of uranium ions from aqueous solutions. © 2011 Desalination Publications. All rights reserved.