A study of the kinetics of isothermal nicotine desorption from silicon dioxide

Abstract

The isothermal kinetics of nicotine desorption from silicon dioxide (SiO 2 ) was investigated. The isothermal thermogravimetric curves of nicotine at temperatures of 115 °C, 130 °C and 152 °C were recorded. The kinetic parameters (E a , ln A) of desorption of nicotine were calculated using various methods (stationary point, model constants and differential isoconversion method). By applying the "model-fitting" method, it was found that the kinetic model of nicotine desorption from silicon dioxide was a phase boundary controlled reaction (contracting volume). The values of the kinetic parameters, E a,α and ln A α , complexly change with changing degree of desorption and a compensation effect exists. A new mechanism of activation for the desorption of the absorbed molecules of nicotine was suggested in agreement with model of selective energy transfer. © 2010 Elsevier B.V. All rights reserved.