Molecular simulation and wetting study on the mechanism and capability of hydrophilic surfactants used as spray dust suppressants for dust reduction in coal mines

Abstract

Coal dust prevention and control has always been a practical problem that needs to be solved urgently in coal mines. Based on spray technology, it has a good application prospect to achieve effective deposition of coal dust by adding surfactants. In this work, the wetting mechanism of three anionic surfactants at the water coal interface was found out from the molecular micro level and macro level through wetting angle test, sedimentation experiment, interfacial tension experiment and molecular dynamics simulation analysis. The results show that the electrostatic potential extremes of sodium sec alkyl sulfonate, sodium fatty acid methyl ester sulfonate and sodium a-alkenylsulfonate are 0.2399 a. u., 0.2430 a. u. And 0.2387 a. u. Respectively, which are greater than the electrostatic potential extremes of water 0.09157 a. u. It can be judged that the head groups of the three surfactants can produce hydrophilicity. The radial distribution function between the S atom and the O atom in the water in the hydrophilic group of the three surfactants has the same overall change trend, forming an obvious first peak and a weak second peak, with molecular diffusion coefficients of 4.633, 11.10, and 14.13 Å2/ps, respectively. The smaller diffusion coefficients correlated with stronger adsorption, which was consistent with contact angle measurements and a relative concentration analysis. The research results can provide reference for efficient evaluation of the wettability of surfactants.