Construction of a three-dimensional energy-stabilized macromolecular model of Daliuta coal and investigation of the influence of weak interactions on wettability: Dust pollution prevention and control

Abstract

Understanding the molecular structure of coal is crucial for gaining insights into the wetting mechanism of coal dust, thus enabling the precise and efficient management of coal dust. After determining the structural information and functional group composition of the coal samples, we continuously adjusted the positions of the groups and the linkages to construct a planar molecular model. Our findings indicate that the Daliuta coal molecule is primarily composed of aromatic carbons, with aliphatic carbons existing in branched form or linked to aromatic rings. The main type of oxygen is carbonyl oxygen, and the molecular formula for Daliuta coal was determined to be C286H263N3O50S. We optimized and annealed the molecular model geometrically, causing the aliphatic bonds in the molecule to undergo numerous deflections and folds, whereas the aromatic structure tended to arrange itself in a laminar pattern due to van der Waals interactions. Given the large number of oxygen-containing functional groups, the electrostatic potential energy contributes significantly to the non-bonding energy, ensuring the stability of the structure. Finally, we obtained the global energy-minimum three-dimensional macromolecular model, establishing the polymerized structure of the coal molecule with a density of 1180 kg/m3. Additionally, we quantitatively analyzed the region of weak interactions between the electrostatic potential on the surface of the coal at the molecular and intramolecular levels. This analysis helped elucidate potential adsorption sites, providing theoretical guidance for modeling the targeted preparation of a spraying dust-reducing agent suitable for this type of coal.