Stabilization of n-aminopropyl Silica Gel against Hydrolysis by Blocking Silanol Groups with TiO2 or ZrO2

  • Autor:

    Abou-El-Sherbini, K. / Pape, C. / Rienitz, O. / Schiel, D. / Stosch, R. / Weidler, P. / Hoell, W. (2010)
  • Quelle:

    J. Sol-Gel Sci. and Tech.,  53 (2010), 3,  587-597
  • Datum: 2010

  • Abou-El-Sherbini, K. / Pape, C. / Rienitz, O. / Schiel, D. / Stosch, R. / Weidler, P. / Hoell, W. (2010): „Stabilization of n-aminopropyl Silica Gel against Hydrolysis by Blocking Silanol Groups with TiO2 or ZrO2“. In: J. Sol-Gel Sci. and Tech.,  53 (2010), 3,  587-597

Abstract

Silanol groups of n-aminopropyl silica gel (APSG) were blocked with TiO2 or ZrO2 to produce Ti-APSG and Zr-APSG, respectively. The silica materials were characterized by infrared, Raman spectra, thermogravimetric, elemental analyses, magic angle spinning 13C-nuclear magnetic resonance, specific surface area measurements, pH-metric titration and inductively coupled plasma—optical emission spectrometry—monitored silica hydrolysis. The stability of APSG against hydrolysis was found to be mainly affected by the specific surface area and the basicity of the n-aminopropyl groups which acquire additional strength from their intramolecular interaction with the silanol groups.

The hydrolysis of silica in Ti-APSG and Zr-APSG remarkably decreased in the range of pH 1.0–9.1 due to the interruption of that intramolecular interaction. The hydrolyzed silica of Ti-APSG and Zr-APSG was decreased to 22.7 and 29.9%, respectively, of that of APSG at pH 4.5. Capacity and stability of Ti-APSG and Zr-APSG were improved in comparison with APSG upon application in the extraction of Cu2+ for 20 cycles of extraction and regeneration.

 

 

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