RECONSTRUCTION OF CALCINED Zn -Al LAYERED DOUBLE HYDROXIDES DURING TETRACYCLINE ADSORPSION
Vìsnik Odesʹkogo Nacìonalʹnogo Unìversitetu: Hìmìâ
Zn-Al mixed oxides containing ZnO different degree crystallinity were obtained by calcinations of Zn-Al layered double hydroxides (LDHs). The reconstruction of calcined Zn-Al LDHs has been performed under stirring in aqueous suspensions. The as-synthesized LDHs, its decomposition products, as well as the reconstructed solids upon hydration were characterized by XRD, N 2 adsorption, differential and thermal gravimetric analysis. It was found that the ability of Zn-Al LDHs to recover a layered
... ecover a layered structure under the hydration of mixed oxides depends on the degree of ZnO crystallinity. The partial reconstruction of Zn-Al layered structure occurs in tetracycline solutions irrespective to the degree of ZnO crystallinity in calcined LDHs. Calcined Zn-Al LDHs demonstrate the higher adsorption capacity to tetracycline in comparison with as-prepared Zn-Al LDHs. The adsorption of TC on calcined and uncalcined ZnAl LDHs occurs on the centers of one particular type. It is suggested that surface complexation of the A-ring ligand of TC with Al-OH centers takes place.