Molecular simulation of the regulation mechanism of the hydrophilic structure of surfactant on the wettability of bituminous coal surface

The regulation of surfactant on the wettability of bituminous coal surface is influenced by its hydrophilic structure. Based on the water absorption simulation and contact angle experiment of bituminous coal under different surfactants, the wetting effect of different surfactants with different hydrophilic structures on bituminous coal was obtained. The mechanism of different surfactants at the coal-water interface was analyzed by molecular dynamics simulation. The frontier orbital distribution and surface electrostatic potential distribution of surfactants and bituminous coal molecules were calculated by quantum chemistry method. The results showed that the wetting effect of surfactants on bituminous coal was APG1214 > OA-12 > SDBS > DTAB. The structure of hydroxyl and amine oxide made surfactants more conducive to promoting the interaction between coal and water molecules. The more oxygen and nitrogen elements the hydrophilic structure contains, the more favorable the surfactant is to modulate the wettability of the bituminous coal surface.