Abstract
Molecular sieves can be used as a host matrix to encapsulate several drugs. Here, we studied the adsorption of acetylsalicylic acid (ASA) in HUS-Y, HZSM-5 and silicalite-1 zeolites, as well as in the mesoporous sieve Si-MCM-41, and compared their adsorption capacities. The materials used generally presented good performance for ASA adsorption. Among the zeolites studied, HZSM-5 adsorbed large amounts of drug than the others. The Si-MCM-41 samples synthesized with fumed silica presented better adsorption performance than those synthesized with tetraethyl orthosilicate. The best mesoporous sample for adsorption synthesized with fumed silica was chosen for the kinetic assay. The adsorption kinetics of ASA for this sample fitted well to a second-order model. The initial loading rate and diffusion coefficient for the ASA–mesoporous sieve system were 0.153% (mg ASA)/(mg solid/minute) and 5.02 × 10−17 m2/s, respectively. The materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen physisorption.