Rapid synthesis of aluminium polycations by microwave assisted hydrolysis of aluminium via decomposition of urea and preparation of Al-pillared montmorillonite

The aim of this work is to provide a new efficient method of preparation of aluminium polycations/oligomers, and especially [AlO4Al12(OH)(24)(H2O)(12)](7+) (Al-13). The microwave assisted forced homogeneous hydrolysis of aluminium through breakdown of urea (M-Al-Urea) is studied and compared with aluminum hydrolyzed with OH- ions (C-Al-OH). M-Al-Urea solutions are characterized by UV-Visible ('Ferron' kinetic assay) and Al-27 NMR spectroscopies. Al-13-sulphate precipitated from M-Al-Urea and C-Al-OH solutions are studied by XRD, TGA and SEM. Al-pillared montmorillonites are prepared with M-Al-Urea solutions as pillaring agent and characterized by XRD, BET, SEM-EDS, TGA and ATR techniques. The advantage of M-Al-Urea solutions as pillaring agent when compared to C-Al-OH is highlighted in the present study. (C) 2009 Elsevier B.V. All rights reserved.