Nuclear Science Research School, Nuclear Science and Technology Research Institute (NSTRI), P.O.B. 11365-3486, Tehran, I.R. IRAN
The main goal of this study is to investigate the capability of zeolites A and P synthesized from Iranian natural clinoptilolite for uranium uptak. The removal of uranium(VI) from aqueous solution via ion exchange by zeolites in a single component system with various contact times, temperatures and initial concentrations of uranium(VI) was investigated. The experimental results were fitted to the Langmuir and Dubinin-Radushkevich isotherms to obtain the characteristic parameters of each model. Both the Langmuir and Dubinin-Radushkevich isotherms were found to good represent the measured adsorption data. Using the thermodynamic equilibrium constants obtained at two different temperatures, various thermodynamic parameters, such as ΔG˚, ΔH˚, and ΔS˚ have been calculated. The thermodynamics of uranium(VI) ion and zeolite system indicates the spontaneous and endothermic nature of the process. It was noted that an increase in temperature resulted in a higher uranium loading per unit weight of the adsorbent.
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