FTIR Spectroscopy of NH3 on Acidic and Ionotropic Alginate Aerogels
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- 作者：Romain Valentin ; Raluca Horga ; Barbara Bonelli ; Edoardo Garrone ; Francesco Di Renzo ; and Franç ; oise Quignard
- 刊名：Biomacromolecules
- 出版年：2006
- 出版时间：March 2006
- 年：2006
- 卷：7
- 期：3
- 页码：877 - 882
- 全文大小：108K
- 年卷期：v.7,no.3(March 2006)
- ISSN：1526-4602
文摘
The acidity of alginate aerogel films has been investigated by infrared spectroscopy of adsorbed NH3. Supercriticaldrying of the alginate provided samples with a surface area of several hundred square meters per gram, in whichthe probe molecule could reach all acidic sites. Free carboxylic groups were studied on acid-gelled alginates andwere found to behave as effective Br
nsted acid sites. Ionotropic alginate gels formed by alkaline earth cationspresented only the Lewis acidity of the cations. Ionotropic gels formed by transition metal cations presented bothLewis and Brnsted sites, because of the presence of a fraction of free carboxylic groups. The incomplete salificationwas correlated to the pH of the gelling solutions.
nsted acid sites. Ionotropic alginate gels formed by alkaline earth cationspresented only the Lewis acidity of the cations. Ionotropic gels formed by transition metal cations presented bothLewis and Brnsted sites, because of the presence of a fraction of free carboxylic groups. The incomplete salificationwas correlated to the pH of the gelling solutions.