Removal of U(VI) and Th(IV) from aqueous solutions by organically modified diatomaceous earth: Evaluation of equilibrium, kinetic and thermodynamic data

• Published in: International journal of mineral processing 2017-11, Vol.168, p.9-18
• Main Authors: Salameh, Slam I.Y., Khalili, Fawwaz I., Al-Dujaili, Ammar H.
• Format: Article
• Language: English
• Subjects: Adsorption; Isotherms; Kinetic; Thermodynamic; Thorium (IV); Uranium(VI)
• ISSN: 0301-7516; 1879-3525
• DOI: 10.1016/j.minpro.2017.08.007

Raw and organically modified diatomaceous earth were used to remove U(VI) and Th(IV) ions from aqueous solution using the batch method. Effects of contact times, dosage of adsorbent, pH, ionic strength and temperature on the adsorption process were studied. The results indicated that the adsorption of these ions was affected by pH and ionic strength. The adsorption isotherms fit the Langmuir, Freundlich and D–R models at different temperature. The kinetic results revealed that pseudo-second-order kinetic model provided the best description of the equilibrium data. Thermodynamic parameters showed the adsorption process was spontaneous and endothermic. The best recovery for U(VI) was obtained when 1.0M EDTA was used as eluent, while for Th(IV) ions when 1.0M HNO3 was used. This paper presents the uptake of U(VI) and Th(IV) ions from aqueous solutions by raw and organically modified diatomaceous earth. [Display omitted] •Raw and organomodified diatomaceous earth (DT-HDTMA) was utilized as an adsorbent.•It was used for the removal of U(VI) and Th(IV) from aqueous solutions.•Adsorption was well described by the Langmuir, Freundlich and D-R isotherm models.•Adsorption kinetics of these ions was found to conform to pseudo-second order model.•The adsorption of U(VI) and Th(IV) on (DT-HDTMA) is endothermic and spontaneous.