Novel zeolite/tobermorite composites were prepared by hydrothermal treatment of a powder-compact consisting of mordenite and slaked lime. Tobermorite formed after the hydrothermal process due to the reaction of mordenite and slaked lime. The bending strength after the hydrothermal process was more than 7 MPa. X-ray diffraction analysis results showed that mordenite remained after the hydrothermal treatment, resulting in the existence of inherent micropores of mordenite in the composites. The composites exhibited a broad mesopore size distribution of more than 6 nm. The improvement in strength, mesopore formation, and specific surface area of the composites depended on the amount and size of the tobermorite that was formed.

A micro/mesoporous composite was prepared by a hydrothermal reaction using mordenite and slaked lime to create a comfortable and safe indoor environment. After the hydrothermal reaction, calcium silicate hydrates formed due to the reaction of slaked lime, mordenite, and quartz, led to the generation of mesopores with a broad pore size distribution of more than 3 nm.In this experiment, the microporous structure of mordenite partially collapsed due to dissolution. As compared with mordenite, the composites exhibited higher water‐vapor adsorption/desorption properties using their mesopores. The amount of adsorbed harmful gases at 70% relative humidity was larger for the composites than for mordenite.