Preparation and characterization of composite scallop shell powder-based and diatomite-based hygroscopic coating materials with metal-organic framework for indoor humidity regulation

Abstract

Abstract Dampness and dryness in buildings have negative effects on occupant s health, building envelope and energy usage. One promising approach is to apply hygroscopic materials with excellent moisture buffering performance in buildings to control the indoor air humidity passively. This paper proposed an innovative application of combination of metal organic frameworks (MOFs) and traditional hygroscopic materials used as passive moisture control coating materials . The scallop shell powder and diatomite, as two kind of substrates, was mixed with 20\xa0wt% zeolite to obtain scallop shell powder-based (SZ) and diatomite-based (DZ) composite inorganic porous mineral materials, respectively. A series of novel composite hygroscopic coating materials (SZ-5, SZ-10 and DZ-5, DZ-10) were prepared by mixing the two composite porous materials with 5\xa0wt% and 10\xa0wt% MIL-100 (Fe) which has excellent performance of water sorption as one kind of MOFs. The microstructures of the produced samples were characterized by nitrogen adsorption/desorption technique and scanning electron microscopy while their hygrothermal properties including the thermal conductivity , the moisture adsorption/desorption performance and the moisture permeability were measured and tested. The results showed that the moisture adsorption amount and moisture adsorption rate for SZ-10 were 0.0121\xa0g/g and 2.29\xa0g/m 2·h, respectively. The diatomite-based sample DZ-10 exhibited greater moisture controlling performance with the moisture adsorption amount of 0.0201\xa0g/g and the moisture adsorption rate of 4.62\xa0g/m2·h, which were 3 and 3.88 times those of the pure diatomite sample. The moisture buffer value (MBV) of DZ-10 were largest, indicating that this sample was the highest efficiency moisture buffering material.