Performance study on synergistic wetting of ionic liquid [C12MIm]Br and surfactant on high-rank coal dust

•The main components and the optimal ratio of the new ionic liquid wetting agent under synergistic wetting were determined.•The variation law of wetting properties of monomer and compound wetting agent on high-order coal dust was analyzed.•The microstructure changes of ionic liquid wetting agent affecting the wettability of high-order coal dust were obtained. High-rank coal dust with high degree of coalification has poor wettability, which in turn affects the dust suppression effect of wetting dust suppressants. This article presents the enhancement of the wettability of bituminous coal and anthracite by surface active ionic liquid [C12MIm]Br and the synergistic wetting effect of [C12MIm]Br with the conventional surfactants, DTAB, SDBS and AEO9. The mixed solution of [C12MIm]Br and AEO9 had the best wetting and sinking effect on high-rank coal dust by surface tension test and sink test. The wettability change of high-rank coal dust modified by monomer and mixed solution indicated that the best wetting effect occurs when the coal dust modified by [C12MIm]Br-SDBS in the mixed solution of [C12MIm]Br-AEO9(15CMC). The adsorption capacity of wetting agents on coal dust surface and the microstructures changes of modified coal dust were studied by UV–visible spectrophotometry and infrared spectroscopy. The results showed that the ether bond functional groups changed obviously and the aliphatic hydrocarbon functional groups increased relatively, revealing the microstructural difference for the enhanced wettability of high-rank coal dust caused by the synergistic wetting effect of [C12MIm]Br and surfactant.