The research found that mixed anionic-nonionic surfactants have synergistic wetting performance which can be added to the spray solution to greatly enhance the wettability to coal dust. In this study, based on the experiment data and some synergism parameters, and a 1:5 ratio of fatty alcohol polyoxyethylene ether sulphate (AES)-lauryl glucoside (APG) has the best synergism, resulting in a highly wettable dust suppressant. Additionally, the wetting processes of different dust suppressant on coal were comparatively simulated by molecular dynamics. Then, the electrostatic potential on the molecular surface was computed. Following this, the mechanism of surfactant molecule regulation of coal hydrophilicity and the advantage of the interspersed arrangement of AES-APG molecules in the mixed solution were proposed. Also, based on the computation of highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) levels and binding energy calculations, a synergistic mechanism of the anionic-nonionic surfactant is proposed from the perspective of enhanced hydrogen bonding between the hydrophilic part of the surfactant and the water molecule. Overall, these results present a theoretical basis and development strategy for the preparation of highly wettable mixed anionic and nonionic dust suppressants for different coal types.
Keywords: Density functional theory (DFT) computation; Mixed anionic-nonionic surfactant; Molecular simulation of dust suppression; Synergistic wetting mechanism.
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