The kinetics of aluminium (III) extraction from sodium hydroxide solutions by an alkylated hydroxyquinoline (Kelex 100)

Abstract

The rate of the extraction of aluminium (III) from sodium hydroxide solutions by 7-(5,5,7,7-tetramethyl-1-octen-3-yl)-8-hydroxyquinoline (Kelex 100, hereafter called HQ) in kerosene has been investigated under non-equilibrium conditions. In the extraction expressed as Al(OH) 4 − (aq) + 3HQ (org)⇌AlQ 3 (org)+OH − (aq)+3H 2O (aq), it was found that the rate of the forward reaction is first order with respect to aluminium concentration in the aqueous phase; and zero and first order at low and higher concentrations of sodium hydroxide, respectively, with respect to the sodium concentration in the aqueous phase and to the Kelex 100 concentration. As a result, it is inferred that aluminium(III) is taken up through the formation of activated species such as [Al(OH) 3] · OH − and Na + [Al(OH) 3] · OH −.