Preparation and selective adsorption of core–shell desiccant for heat and moisture recovery

To improve indoor air quality, a type of highly selective desiccant with core–shell structure, which can adsorb more moisture and less toluene, was developed for heat and moisture recovery. Three desiccants (MS-NH2-MAS, MS-NH2-PAAS, and MS-NH2-PSS) with different shells were successfully prepared by selective amine-functionalization of mesoporous silica (MS) external surface, and subsequent assembly with sodium malate (MAS), sodium polyacrylate (PAAS), and sodium polystyrene sulfonate (PSS) as modifying agent, respectively. N2-adsorption isotherms showed that the novel core–shell desiccants had the similar pore structure to MS. The adsorption performances were evaluated by the breakthrough test. Compared to MS, these novel desiccants exhibit much higher selectivity and larger adsorption capacity of moisture because of their enhanced affinity for moisture. The moisture/toluene selectivities of MS-NH2-MAS, MS-NH2-PAAS, and MS-NH2-PSS are 4.7, 3.2, and 2.8 times than that of MS, respectively.