日本ゼオライト学会　刊行物 Publication of Japan Zeolite Association

Physical adsorption, chemisorption, absorption and occlusion as the typical interaction between a gaseous molecule and solid can be classified by the structural change in the molecule and/or solid on the mutual interaction. Physical adsorption, of which attractive interaction originates from dispersion interaction, does not change both structures of the molecule and solid. However, physical adsorption in nanopores is highly enhanced due to the overlapped interaction potential between the molecule and pore wall; various kinds of nanoporous solids exhibit characteristic adsorption behavior. Porous coordination polymer (PCP) crystals having pillar frame structure can have larger surface area than other nanoporous solids consisting of wall frame structure such as zeolite and porous carbon. Some of PCP crystals have flexible nature, showing gate adsorption. Quantum molecular sieving effect is a new phenomenon in physical adsorption. Hydrogen isotopes can show different adsorption behavior due to the difference in the quantum fluctuation relating to the molecular weight; the quantum fluctuation difference in the isotopes gives a marked difference in adsorption in nanopores at low temperature. Water adsorption on nanoporous carbon of hydrophobicity shows apparent hydrophilicity depending on the matching between the pore width and cluster size of water molecules.