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Preparation of the Precursor of the Zirconium Oxide in EDTA−Ammonia Solution by the Sol−Gel Method

1997; American Chemical Society; Volume: 36; Issue: 6 Linguagem: Inglês

10.1021/ie9607210

1520-5045

Maw‐Ling Wang, Biing‐Lang Liu, Chi-Chun Ren, Zong‐Whie Shih,

Chemical Synthesis and Characterization

The sol−gel method was employed to prepare the precursor of zirconium oxide by the reaction of zirconyl chloride octahydrate (ZrOCl2·8H2O and EDTA in ammonia. The reaction of ZrOCl2· 8H2O and the ionized complexing agent R(COO-)n was achieved through sequential hydrolysis (4ZrOCl2·8H2O + 20H2O → [Zr4(OH)8(OH2)16]8+ + 8Cl-) and polymerization ([Zr4(OH)8(OH2)16]8+ + R(COO-)n → [Zr4(OH)8-n(OH2)16(−OOC)nR]8+ and [Zr4(OH)8(OH2)16-n(−OOC)nR]8+). The effect of the reaction conditions, including temperature, the molar ratio of ZrOCl2·8H2O, the content of NH3, and the agitation speed on the particle size distribution, the average size of particle, and the viscosity of the sol are investigated in detail. A rational reaction mechanism, which accounts for the formation and the growth of the particles and the viscosity of the sol, is proposed to explain the experimental results satisfactorily.