Effect of Surfactant Adsorption on the Wettability of FAU-Type Zeolite: A Molecular Dynamics Study

The effective capture of industrial zeolite dust using advanced air purification technologies hinges on controlling the interfacial wettability of these porous particles. In this work, molecular dynamics simulations were used to elucidate the molecular mechanisms underlying surfactant-modulated wetting behavior at porous FAU-type zeolite surfaces. Different surfactants (SDBS, DTAB, AEO9), solid surface crystal facets (FAU(100) and FAU(111)), and initial surfactant orientations were considered. The FAU-water interaction energy indicates that all three surfactants can enhance wetting on both crystal facets, with DTAB showing the strongest enhancement in selected conformations. Owing to the porous structure and the nonuniform electrostatic distribution of the FAU surface, ionic surfactants can penetrate the FAU pores under the combined influence of electrostatic attraction of the charged headgroups and hydrophobic driving forces of the alkyl chains. The penetration of the surfactant not only improves wettability but also enhances the connection stability required for dust agglomeration. Furthermore, residence time and local diffusion analyses show that surfactants can enhance interfacial water structuring and reduce the mobility of water molecules, and confirm the superiority of DTAB. These results offer a molecular-level basis for surfactant-assisted zeolitic dust suppression and the design of wetting agents for porous materials, with potential implications for improving dust capture, reducing airborne particle exposure, and supporting safer industrial dust-control practices.