Preparation of silicas impregnated with HPBI, HPMSP and DEHPA and their application in the solid–liquid extraction of Cu(II) and Zn(II)

The synthesis of mesostructured silicas impregnated with acidic chelators, an acylisoxazolone 3-phenyl-4-benzoyl-5-isoxazolone (HPBI), an acylpyrazolone 1-phenyl-3-methyl-4-stearoyl-5-pyrazolone (HPMSP) and an organophosphoric acid di-(2-ethylhexyl)-phosphoric acid (DEHPA) was undertaken. The different solids were characterized by physico-chemical methods: XRD, FTIR, thermal analysis, TEM, and N2-sorption. The porous integrity of the silica was preserved after impregnation. The amount of ligand was evaluated by UV–Visible analysis of washings, weight loss after calcination and thermal analysis. More than 90% of the ligand used for the impregnation was trapped into the functionalized solids. These materials achieved encouraging extractive performances in removing copper with HPBI below pH 1 and in removing zinc with DEHPA below pH 3 in sulfate media.