STUDY OF PILLAR PRECURSORS [GA(III)-AL(III), LN(III)-AL(III), ZR(IV)]FOR HYDROTHERMALLY STABLE PILLARED CLAYS

Citation
Jm. Dominguez et al., STUDY OF PILLAR PRECURSORS [GA(III)-AL(III), LN(III)-AL(III), ZR(IV)]FOR HYDROTHERMALLY STABLE PILLARED CLAYS, Catalysis today, 43(1-2), 1998, pp. 69-77
Citations number
17
Categorie Soggetti
Engineering, Chemical","Chemistry Applied","Chemistry Physical
Journal title
ISSN journal
09205861
Volume
43
Issue
1-2
Year of publication
1998
Pages
69 - 77
Database
ISI
SICI code
0920-5861(1998)43:1-2<69:SOPP[L>2.0.ZU;2-M
Abstract
The hydrolysis of mixed solutions of AI(III), Ga(III), Al(III), Ln(III ) and Zr(IV) was studied by potenbometric, spectrophotometric and Al-2 7- and Ga-71-NMR techniques. For the AI-Ga system formation of GaAl12( OH)(28)(11+) species seems more probable into the pH range 4 less than or equal to pH less than or equal to 5. Afterwards, the Al-13(OH)(32) (7+) species predominate in agreement with thermodynamic data obtained by SUPERQUAD program. Both tetrahedral Ga-IV and Al-IV may coexist in solution, the interval being defined by potentiometric methods. For t he Ln(III)-Al(III) systems Al-27-and La-139-NMR does not confirm the c hemical interaction between the two species in solution, but the physi cochemical properties of the La-Al/PILCS were different than Al/PILCS, suggesting a strong interaction in the solid state. Ce(III) and Ce(IV ) ions do interact with AI(III) in solution, into the pH range 2.78<pH <3.99, according with the spectrophotometric behavior. Finally, the Zr (IV) hydrolysis was followed by UV in the pH range greater than 2.0, s howing the formation of Zr-4(OH)(8)(8+) species, which was verified by calculations using SQUAD program, but the precipitation occurs at pH> 3.0. (C) 1998 Elsevier Science B.V. All rights reserved.