Effect of Sodium Dodecylbenzene Sulfonate on the Wetting Mechanism of Tunliu Coal.

Coal dust in the coal mining process may lead to a serious threat to the safety and health of miners. The addition of surfactants during coal seam water infusion can significantly improve the effect of dust suppression, so it is crucial to study the influence mechanism of surfactants on coal wettability. The variation of the hydration film thickness on the Tunliu coal surface at different concentrations of sodium dodecylbenzene sulfonate (SDBS) solution was investigated by atomic force microscopy. The experimental results indicate that the hydration film thickness increases initially and decreases afterward with the SDBS solution concentration increase, with a maximum value of 11.4 nm. The surface free energy (SFE) of coal molecules adsorbed with different numbers of SDBS molecules were calculated using two coal molecule cell models developed by Materials studio 8.0, and the simulation results display a good agreement with the experiments. The higher the SFE, the greater the hydration film thickness on the coal surface, and the stronger the enhancement effect of SDBS solution on the wettability of coal at the corresponding concentration. The interface formation energy (IFE) and cohesive energy density (CED) of coal molecules after adsorption of SDBS molecules were calculated separately. It was found that when three SDBS molecules were adsorbed, the absolute value of IFE and CED reached the maximum, and each SDBS molecule had the strongest average effect on coal molecules, the bond between them would be tighter. SFE simulations are helpful to optimize the selection of surfactants for practical engineering applications. [ABSTRACT FROM AUTHOR]