Grand Canonical Monte Carlo (GCMC) was used to study the sorption thermodynamics of carbon dioxide in model graphite slit-like pores and nanotubes by means of the Ewald technique, suitably adapted for the computation of long range (electrostatic) interactions of sorbates confined in pore systems exhibiting reduced periodicity in space. The computed thereby micropore size distributions extracted via mathematical elaboration of the simulation results with respect to real graphitic materials, reproduced successfully the experimentally measured isotherms of carbon dioxide in these materials at various temperatures. In the case of nanotubes, a direct Coulomb summation over a large number of periodic images proved to be a sufficient approximation leading to excellent agreement between the simulated and measured isotherms. (C) 2007 Elsevier B.V. All rights reserved.