Role of Roughness Change on Wettability of Taixi Anthracite Coal Surface before and after the Heating Process

It is well-known that the heating process can change the composition of functional groups on the coal surface and the change of the composition of functional groups can change the hydrophobicity and wettability of the coal surface. The change of coal surface topography, such as surface roughness, is usually ignored during the heating process. Therefore, the effect of the change of surface roughness on the hydrophobicity and wettability of the coal surface is also sufficiently studied. This investigation is to find out the changes of the composition of functional groups and roughness on the Taixi anthracite coal surface before and after the heating process in a quartz crucible. The effects of these changes on the wettability of the anthracite coal surface will be discussed. The composition of functional groups on the coal surface before and after the heating process was characterized by X-ray photoelectron spectroscopy (XPS), and the wettability of the coal surface was indicated by contact angle measurements. The heating process temperature was 600 °C, and the heating process time was 120 min. Throughout this paper, it was found that the surface roughness change before and after the heating process had a significant role on the wettability of the coal surface.