Modulation of asbestos wettability: A mechanistic exploration of experimental and molecular modeling of surfactant types

Surfactant type is a key parameter affecting the interaction of water molecules with surfactants and its mechanism for regulating the wetting properties of asbestos has not been fully elucidated. In this paper, a combination of experiments, quantum chemical calculations, and molecular dynamics simulations has been utilized to thoroughly analyze the wetting properties of different surfactants on asbestos. The experimental results indicated that the contact angle decreased significantly with increasing concentration at surfactant levels below 0.05 wt%, reaching 0.09 wt% where AES demonstrated the most effective wetting. Depth-of-field microscopic observations showed that surfactant treatment could significantly reduce the roughness of the asbestos surface, decrease the number of pores and cracks, and enhance the dust suppression effect. Quantum chemical calculations revealed that the AES molecule promotes electrostatic adsorption with asbestos and improves wetting properties due to the strong negative ESP of its oxyethylene and sulphonate groups. Molecular dynamics simulations provide additional insights into how different surfactant types affect the wettability of asbestos, indicating that electrostatic interactions are crucial in determining the adsorption of water molecules. The hydrophilic groups of AES are positioned nearer to the asbestos surface, enhancing the adsorption of water molecules onto it. Combining experimental and simulation findings, the wettability of the eight surfactants on asbestos was AES > SDBS > AEO 3 > BS-12 > CAB-35 > AEO 9 > DTAB > CTAB. This study affirmed the outstanding effect of AES as a potential surfactant for asbestos wetting and also furnished a theoretical foundation for exploring the mechanism of asbestos wetting. • Additional groups increase intermolecular repulsion and affect surface tension. • Surfactant treatment reduces asbestos roughness, porosity and number of cracks. • AES's negative ESP of oxyethylene and sulphonate groups enhances electrostatics. • AEO 9 has more hydrogen bonding receptors and binds water molecules more strongly.