Structural and adsorption characteristics of pyrogenic nano silica, aluminum-and titanium-silicas modified with polyvinyl alcohol and polyethylene glycol

• Date: 2006
• Main Authors: Zarko, V. I., Andriyko, L. S., Gun'ko, V. M., Malysheva, M. L., Gatskiy, O. A., Gerashchenko, I. I.
• Format: Article
• Language: Russian
• Published: Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2006
• Online Access: https://surfacezbir.com.ua/index.php/surface/article/view/191
• Journal Title: Surface

Adsorption of linear polymers (poly(vinyl)alcohol (PVA), poly(ethylene)glycol (PEG)) onto surface of fumed oxides was measured by viscosimetric method. According to the IR spectroscopy data, a portion of surface hydroxyls does not interact with polymer molecules at monolayer coverage with PVA while PEG monolayer disturbs all the free surface hydroxyls. Thermostimulated depolarization current study of aqueous suspensions of nanooxides showed that modification of oxide surfaces with polymers changes conditions of water clustering at the oxide-water interface. The nature of both surface active sites and modificator functionalities is determinative factors of the adsorption. The modification effect on the adsorption of heavy metal ions was studied by using adsorption and potentiometric titration methods. The polymer monolayer coverage of fumed oxides enhances the adsorption of metal ions at pH < 7. At pH > 7 PVA adsorbed on silica does not enhances the Cu(II) adsorption while adsorbed PEG leads to the opposite result because it has the electron donor functionalities (C-O-C) only, in contrast to PVA having COH groups with both electron-donor and proton-donor properties.