Synthesis of a novel porous diatomite/AlOOH composite material and its humidity control performance

Using diatomite (DE) as the micro-reactor and carrier, the diatomite/AlOOH porous humidity control material (DE/A) was prepared via joint hydrolytic precipitation and hydrothermal treatment. The samples obtained were thoroughly characterized by XRD, ICP-MS, FTIR, nitrogen adsorption, MIP, fractal theory, SEM, EDS, TEM and contact angle for reaction mechanism, surface properties, pore structure, fractal character, and morphology analysis. The humidity control performance and reusability of samples were tested. The thermodynamics analysis was also investigated according to Clausius–Clapeyron equation. The results indicated that DE/A showed a better humidity control performance than DE under different relative humidity and temperature. DE/A also showed good reusability. Humidity control performance of DE was significantly improved with the increasing of mesoporous and hydroxyl content. The structure heterogeneity and surface energy of DE were enhanced. A more reasonable pore size distribution had formed in the DE. Van der Waals force and hydrogen bonds are the main forces for humidity control.