To the question of the influence of a silanol cover on the protolytic properties of aminopropyl silica gels

Abstract

The paper proposes a model that describes the acid-base properties of amino groups grafted onto the surface, taking into account their interaction with silanol groups. For this, aminopropyl silica was chosen as an object with well-studied methods of preparation, structure and properties. The isotherms of sorption of hydrogen ions on aminopropyl silica were obtained by potentiometric method. The experimental points were analyzed numerically, taking into account the presence of an electric double layer, the presence of surface processes competing with the sorption of hydrogen ions, and the peculiarities of the behavior of silanol groups when the degree of surface filling with hydrogen ions changes. The resulting model makes it possible to carry out a preliminary calculation of the sorption of hydrogen ions on the surface of aminopropyl silica.

Keywords

• functionalized sorbents
• aminopropyl silica
• protolytic properties
• curves of potentiometric titration of sorbents