Abstract: Conventional silicalite-1 (S-1) zeolite exhibits limited efficiency in adsorbing polar volatile organic compounds molecules (e.g., acetone) due to its scarcity of acid sites. Based on this, a series of metal-encapsulated S-1 zeolites were prepared by introducing metals Ag, Cu, Fe, and Ni into S-1 via in-situ synthesis. Systematic characterization and acetone adsorption performance tests were conducted on both S-1 and the metal-encapsulated S-1 zeolites. The results show that Fe@S-1 exhibits the best acetone adsorption performance, with its acetone adsorption breakthrough capacity increasing by approximately 10% compared to that of S-1. This improvement is attributed to the introduction of Fe, which significantly enhances the microporous specific surface area and the number of Lewis acid sites in S-1. As the Fe loading increases, the number of Lewis acid sites in Fe@S-1 shows an upward trend, and the crystal grains gradually decrease in size, forming aggregated particles with intercrystalline mesopores. These characteristics not only enhance the adsorption of acetone on Fe@S-1 but also reduce the diffusion resistance of acetone, thereby improving its adsorption capacity for acetone. The fitting results of the adsorption kinetic model indicate that the adsorption behavior of acetone on Fe@S-1 is governed by both physisorption and chemisorption, with intraparticle diffusion playing a dominant role in the adsorption process.

Key words: S-1 zeolite, metal encapsulating, Lewis acid site, acetone, adsorption, volatile organic compounds