Monte Carlo Simulation Study of Water Adsorption in Activated Carbon

We present a Monte Carlo simulation study of adsorption and desorption for two molecular models of water in activated carbon, focusing on the temperature range for which the system exhibits hysteresis. The activated carbon is modeled using an adaptation of the platelet model developed by Segarra and Glandt (Chem. Eng. Sci. 1994, 49 (17), 2953-2965). The active sites in the carbon are modeled by placing interaction sites at the periphery of the platelets. To model water we have used two model potentials: the simple point charge (SPC) model and adaptation of the primitive model of water developed by Kolafa and Nezbeda (Mol. Phys. 1987, 61 (1), 161-175). We find that both models considered yield quite good qualitative agreement with the experimental data for water in BPL carbon obtained by Levan and co-workers (Ind. Eng. Chem. Res. 1992, 31 (4), 1122-1130). In particular both the shape of the hysteresis loops and their temperature dependence are correctly described by the simulation results. The sensitivity of the results to changes in the model parameters is investigated.