In this paper, the liquid-solid extraction of thorium(IV) by sodium bentonite and magnetic bentonite is reported. Magnetic adsorbent can
be quickly separated from a medium by a simple magnetic process. Various parameters have been studied to assess the performance
of maghemite nanocomposite clay for the removal of Th(IV). The operating variables studied are initial Th(IV) concentration, pH, ionic
strength, temperature and contact time. The time needed for magnetic bentonite to adsorb the maximum of Th(IV) is 45 min and 60 min for
sodium bentonite. For magnetic bentonite, optimal extraction yield was achieved at an initial pH equal at 6.2 and for sodium bentonite, the
variation of initial pH has no influence on the extraction yield. The sorption capacities of sodium bentonite and magnetic bentonite are
41.24 and 31.34 mg.g-1
respectively. Adsorption equilibrium data were calculated for Langmuir and Freundlich isotherms. It was found that
the sorption of Th(IV) on sodium and magnetic bentonite was better suited to the Langmuir adsorption model. Thermodynamics data leads
to endothermic and spontaneous process for magnetic bentonite and exothermal for sodium bentonite. The quantitative elution study of
thorium can be realized with acetic acid for sodium bentonite and sulfuric acid for magnetic bentonite.
Key words: Bentonite; nanoparticle; isotherm; thorium; magnetic process
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