Lithium adsorption on amorphous aluminum hydroxides and gibbsite

Abstract

Lithium (Li) adsorption on both amorphous aluminum hydroxides and gibbsite was studied. For the amorphous Al(OH)₃ the adsorption was found to be pH dependent. Generally, 1.6 times more Li was adsorbed at initial pH value 8.0 compared with pH value 6.50. Gibbsite adsorbed 11.6 to 45.5 times less Li quantities compared with amorphous Al(OH)₃. Lithium adsorption was not depended on equilibrium times. It remained stable for all equilibrium times used. Lithium quantities extracted with 1N CH₃COONH₄  pH 7 , represent the physical adsorption, while the remaining Li that was adsorbed on Al(OH)₃, represents the chemical adsorption. During the desorption process 19% of Li extracted with NH₄⁺, represents the physical adsorption, while the remaining 81% of Li, which was adsorbed represents the chemical adsorption. In gibbsite, 9.6% of Li represents the physical adsorption and 90.4% the chemical one. The experimental data conformed well to Freundlich isotherm equation.

Keywords

• Adsorption, aluminum hydroxides, desorption, lithium

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