Stabilization of Quercetin - Functionalized Silica Gel against Hydrolysis by Blocking Silanol Groups with TiO2 or ZrO2 and Its Application for the Separation of Hg(II)

  • chair:

    Abou-El-Sherbini, K. / Schiel, D. / Stosch, R. / Weidler, P. / Hoell, W. (2011)
  • place:

    J. Sol-Gel Sci.Technol. 57 (2011), 1, 57-67
  • Date: 2011

  • Abou-El-Sherbini, K. / Schiel, D. / Stosch, R. / Weidler, P. / Hoell, W. (2011): „Stabilization of Quercetin - Functionalized Silica Gel against Hydrolysis by Blocking Silanol Groups with TiO2 or ZrO2 and Its Application  for the Separation of Hg(II)“. In: J. Sol-Gel Sci.Technol. 57 (2011), 1, 57-67

Abstract

Free silanol groups of silica-gel functionalized with quercetin (QSG) were blocked with TiO2 or ZrO2 to produce TiO2-QSG and ZrO2-QSG, respectively. The silica materials were characterized by infrared, Raman spectra, thermogravimetric, elemental analyses, magic angle spinning C-13-nuclear magnetic resonance, BET specific surface area measurements and inductively coupled plasma-optical emission spectrometry-monitored silica hydrolysis. Siloxane groups are reinforced in the blocked QSG samples without affecting the hydrophilic nature or the porosity of silica.

Quercetin is unaffected by the titania layer in contrary to zirconia. Also, the stability of silica against hydrolysis in TiO2-QSG and ZrO2-QSG was remarkably improved in the range of pH 3.5-9.1, attributed to the interruption of the intramolecular interaction of silanol groups with the amino groups. The hydrolyzed silica of TiO2-QSG and ZrO2-QSG decreased to 46.6 and 18.5%, of that of QSG and to 7.6 and 3.1%, of that of 3-aminopropylsilica gel at pH 9.1, respectively. TiO2-QSG was applied for the extraction of HgII with separation efficiency of 99.0 +/- A 0.6% at pH 8.5.

The capacity loss of TiO2-QSG per recovery cycle of HgII was lowered in comparison with the uncovered material. It was successfully applied for the recovery of HgII from spiked water and referenced samples.

 

 

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