Adsorption and thermodynamic behavior of uranium(VI) on Ulva sp.-Na bentonite composite adsorbent

Abstract

The algae-clay composite adsorbent was tested for its ability to recover U(VI) from diluted aqueous solutions. Macro marine algae (Ulva sp.) and clay (Na bentonite) were used to prepare composite adsorbent. The ability of the composite adsorbent to adsorp uranium(VI) from aqueous solution has been studied at different optimized conditions of pH, concentration of U(VI), temperature, contact time. Parameters of desorption were also investigated to recover the adsorbed uranium. The adsorption patterns of uranium on the composite adsorbent followed the Freundlich and Dubinin-Radushkevich isotherms. The thermodynamic parameters such as the enthalpy ?H, entropy ?S and Gibbs free energy ?G were calculated from the slope and intercept of lnKd vs. 1/T plots. The results suggested that the Ulva sp.-Na bentonite composite adsorbent is suitable as sorbent material for recovery and biosorption/ adsorption of uranium ions from aqueous solutions. © 2005 Akadémiai Kiadó.