Effects of water-based SiO2 nanofluids on the wettability of coal dust and particle deposition characteristics

Coal wettability plays a crucial role in the prevention of coal mine dust and associated disasters such as coal and gas outbursts. Water-based SiO2 nanofluids have emerged as promising wetting agents because of their sustainable wetting effects on coal. However, the current research on the wetting characteristics of nanofluids has predominantly focused on small coal fragments, with limited studies on coal dust. This study aims to investigate the influence of water-based SiO2 nanofluids with varying particle concentrations on the wettability of coal dust via physical experiments. The findings revealed that the modification by nanofluids significantly reduced the contact angles of the coal dust particles with the particle size ranges of 60-80, 80-100, and 100-150 mesh, compared to the initial contact angles. Moreover, higher particle concentrations resulted in smaller contact angles. Notably, the wetting effects of the nanofluid modification on coal dust were particularly prominent for larger particles. Furthermore, compared with water immersion, nanofluid modification demonstrated a significantly more positive impact on the wettability of coal dust. Notably, the SiO2 nanoparticles exhibited a wide distribution and substantial adsorption capacity on the coal surface, enabling the formation of a hydrophilic structure coverage. This study contributes to a comprehensive understanding of the wetting behavior of coal dust when exposed to water-based SiO2 nanofluids. These findings underscore the potential of nanofluids to enhance coal dust prevention and control, and provide valuable insights for future research in this field. (c) 2023 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/4.0/).