Adsorption equilibrium and kinetics of U(VI) on beta type of akaganeite

The use of cheap, high efficiency and low-risk adsorbent has been studied for the removal of U(VI) from aqueous solutions. A series of experiments was conducted in a batch system to assess the effect of the system variables, i.e. initial pH, temperature, initial uranium concentration and contact time. The results of these parameters were given in the previous work. In this paper Langmuir, Freundlich, Temkin, Dubinin-Radushkevich (D-R) and Harkins-Jura isotherms were used to analyze the equilibrium data at different temperatures. Adsorption process fitted to Langmuir and Temkin isotherm models. Also the adsorption kinetics was found to follow pseudo-second-order rate kinetic model, with a good correlation (R(2)>0.99) and intraparticle diffusion as one of the rate determining steps. The findings of this investigation suggest that the chemical sorption plays a role in controlling the sorption rate. (C) 2010 Elsevier B.V. All rights reserved.