Abstract:

To investigate the microscopic mechanisms and effectiveness of composite foam dust suppressants under various mixing ratios, a foam liquid film model constructed from anionic surfactant sodium dodecyl sulfate (SDS) and nonionic surfactant polyoxyethylene monolauryl ether (C₁₄E₃) was employed. Molecular dynamics simulations were utilized to study the microscopic dynamic evolution and thermodynamic properties of SDS/ C₁₄E₃ composite foam dust suppressants in different mixing ratio systems. The results indicate that the combination of SDS and C₁₄E₃ further enhances the ability of SDS head groups to immobilize water molecules. When the SDS/C₁₄E₃ ratio is 12∶24, the interaction between SDS head groups and water molecules is the strongest. The diffusion coefficients of the bound water and SDS head groups in the composite foam liquid film exhibit a ″V″-shaped variation with the mixing ratio. The ability of SDS head groups to immobilize bound water in the composite foam liquid film is significantly stronger than that of single surfactant foam liquid films, with the weakest diffusion capacity between head groups and water molecules is observed at an SDS/C₁₄E₃ ratio of 12∶24. The surface tension of the composite foam liquid film decreases initially and then increases with the increase in the SDS ratio. The liquid film exhibits the best wettability when the SDS/C₁₄E₃ ratio is 12∶24.

Key words: molecular dynamics, foam dust suppressant, mixing ratio, surfactant, interaction