Solid‐Liquid Extraction of Lanthanum(III), Europium(III), and Lutetium(III) by Acyl‐Hydroxypyrazoles Entrapped in Mesostructured Silica

Abstract

The solid-liquid extraction of lanthanum(III), europium(III), and lutetium(III) by mesostructured silicas doped with 1-phenyl-3-methyl-4-stearoyl-5-pyrazolone (HPMSP, bearing one chelating site) or with 1,12-bis(1 0 -phenyl-3 0 -methyl-5 0 -hydroxy-4 0 -pyrazolyl)-dodecane-1,12-dione (HL-10-LH, bearing two chelating sites) has been studied and compared to the analogous solvent and micellar extractions in terms of the stoichiometry of the extracted complex and of the extraction efficiency. The solid-liquid extraction order in the lanthanoid series is La , Eu , Lu; it is the usual liquid-liquid extraction order obtained with acidic extractants. A theoretical model is used to determine the stoichiometries of the extracted complexes and the extraction yield is measured as a function of the pH, of the extractant/metal ratio (S/M) and of the volume ratio of the two phases (f). For HPMSP, the extracted complexes involve three ligand molecules for one metal. For HL-10-LH, the complex stoichiometries are found to be either Ln(L-10-L)(L-10-LH) (Ln ¼ La, Eu) or Lu 2 (L-10-L) 3 for S/M ¼ 25, or Eu 2 (L-10-L) 3 for S/M ¼ 5. For the first time, the synergistic solid-liquid extraction is studied after a successful attempt at simultaneously immobilizing both extractants HL-10-LH and 2,4,6-tri(2-pyridyl)-1,3,5-triazine, "TPTZ", into silica; the complex extracted in this case differs from the one obtained in solvent extraction.

Highly Efficient Extraction Separation of Lanthanides Using a Diglycolamic Acid Extractant

“…The extraction efficiency of Ln cations using neutral Lewis-base-type extractants increases with increasing anion concentration, whereas Ln transfer using ionizable Brønsted-acid-type extractants can be simply controlled by the pH of the aqueous phase, and involves no anionic species. Although CHON-based extractants incorporating Brønsted acids such as carboxylic acids [19][20][21][22][23] or β-diketones 24,25 have also been developed for the extraction of Ln cations, almost all of these extractants have very low extraction and separation performances for Ln cations because of their poor coordinating ability and selectivity for Ln cations. The development of Brønsted-acid-type extractants based on the CHON-principle, with superior extraction separation abilities relative to organophosphorus compounds, represents a challenging task.…”

Silica-based monoliths functionalized with DTPA for the removal of transition and lanthanide ions from aqueous solutions

“…A variety of solid sorbents have been studied with respect to this aim, such as porous silica, [19][20][21] clays, [22][23][24] metal-organic frameworks (MOFs), [25][26][27] nanoparticles, 28,29 metal oxides [30][31][32] and composite 2D materials. 33,34 Among porous materials, mesoporous silica monoliths have been recently proposed for the removal of several contaminants in water and gaseous media (i.e.…”

“…A variety of solid sorbents have been studied with respect to this aim, such as porous silica, 19–21 clays, 22–24 metal–organic frameworks (MOFs), 25–27 nanoparticles, 28,29 metal oxides 30–32 and composite 2D materials. 33,34…”