The influence of adsorbent on the kinetics of (photo)catalytic oxidation processes was studied using the simple single and double stage reaction mechanisms with the adsorption stages corresponding to Langmuir model. It was found that in the static reactor in all cases the usage of adsorbent leads to the prolongation of substrate (A) removal and product (P) accumulation kinetic curves but the substrate concentration becomes lower during almost all (photo)catalytic process. Fitting of experimental data points of acetone photocatalytic oxidation reaction demonstrated a good correlation with proposed reaction mechanism. Calculated adsorption constants values are close to those reported in literature. The using of adsorbent in flowing conditions leads to the decrease of maximum outlet substrate concentration in the case if the inlet substrate concentration is too high to be oxidized completely for one run. Kinetics simulation in the case of (photo)catalytic reaction with intermediate demonstrates that adsorbent could accumulate additional intermediate quantity thus keeping catalyst surface more active and contributing to faster substrate (A) removal. (C) 2010 Elsevier B.V. All rights reserved.