“…However, it was found that in the initial period ( 24 h), phosphate ions complex onto the oxide surface in a 1:1 stoichiometry at a fairly rapid rate, and then, in an extended period ( 25 h), the alumina phase transforms into an aluminum phosphate precipitate at a very slow rate [14]. Additionally, it was found that in the pH range 1.7-2, 80% of the Th(IV) appears as Th(H 2 PO 4 ) 4 , at pH 3, and the anionic complex is predominant and incorporates 90% of the thorium at solution conditions C H 3 PO 4 7 × 10 −2 mol/L and C Th ≈ 3 × 10 −4 mol/L [10]. Therefore, a strong effect of phosphate on the extent of adsorption of Th(IV) onto alumina may be expected.…”