Adsorption of quercetin at the surface of particles of a silver sol in ethanol

Isotherms of quercetin adsorption from ethanol solutions on the surface of silver sol particles were measured in the temperature range from 289 to 308 K. It was established that the adsorption rate and the limiting equilibrium amount of dye adsorbed increase with temperature. An analysis of the absorption spectrum of the silver sol within the framework of the Mie theory and the theory of plasma-resonance absorption showed that the electron density of adsorbed quercetin molecules is shifted to the metal, and, consequently, adsorbed ethanol (and water) molecules are not displaced. The increase in the amount of adsorbate with temperature was explained by the formation of new adsorption sites, with which quercetin molecules form hydrogen bonds.