Influence of Mixed Surfactant Systems Comprising Anionic and Nonionic Surfactants on the Wettability of Anthracite

To enhance the wetting performance of underground anthracite dust in coal mines, Jincheng anthracite was selected as the research object, and experimental measurements were combined with molecular simulations to systematically investigate the synergistic enhancement mechanism of a binary anionic/nonionic surfactant system composed of nonionic CDEA and anionic FMES. Composite solutions were prepared at different mass ratios of CDEA to FMES (4:0, 3:1, 2:2, 1:3, 0:4). Their wettability was evaluated by contact-angle measurements, and the microscopic synergistic mechanism was further elucidated by molecular dynamics simulations and quantum-chemical calculations. The results show that the blended system exhibits significantly better wettability than either single component, and that the synergistic effect is strongest at a CDEA:FMES mass ratio of 1:3, where the contact angle reaches a minimum of 20.90° and the wetting rate is the highest. Molecular simulation indicates that, at this ratio, surfactant molecules adsorb more compactly on the coal surface and exhibit larger adsorption energy, which promotes the spreading of water molecules. These findings provide a theoretical basis for dust suppression in underground anthracite mines.