Water adsorption in active carbon characterized by adsorption and immersion techniques

The preadsorption of variable amounts of water, followed by the adsorption of nitrogen at 77 K or the immersion into water at 293 K has been examined for a set of well characterized active carbons. The results confirm the model proposed by Dubinin, suggesting that water forms clusters around primary centres, rather than filling the micropores by capillary condensation. The primary centres are occupied gradually, as adsorption proceeds. This is also suggested by immersion into benzene, which appears to displace completely the adsorbed water.