MONTE-CARLO SIMULATION OF SILICA SURFACE DEHYDROXYLATION UNDER NONISOTHERMAL CONDITIONS

The influence of distance between OH groups and lattice disorder of si lica surface on the peak characteristics in the TPD (temperature progr ammed desorption) spectra of water desorption as well as on the covera ge dependence of desorption activation energy has been investigated by the Monte Carlo simulation. The experimental TPD spectra of water des orption from different silica samples and coverage dependencies of des orption activation energy have been compared. The BOC-MP approach has been used to calculate the activation energies for possible associativ e desorption reactions which are realized during the dehydroxylation. It was established that most activation energies for associative desor ption lie in the same region as those estimated from the TPD spectra.