Mechanism and Effect of Surfactants on the Wettability of Anthracite Coal

Abstract

The wettability of anthracite is crucial for effective dust control in industrial dust removal processes. This study investigates the key effects of surfactants on the wettability of anthracite by compounding anionic surfactants, specifically fatty acid methyl ester ethoxylate sulfonate (FMES), with nonionic surfactants, such as coconut oil fatty acid diethanolamide (CDEA). The research analyzes the surface chemical properties and agglomeration behavior of the treated anthracite. The processed coal samples were characterized using various techniques, including infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The experimental results indicate that the anionic-nonionic composite surfactant exhibits a significant synergistic effect in enhancing the wettability of anthracite coal. SEM and EDS analyses revealed that the coal samples treated with surfactants formed liquid bridges through hydrogen bonding, which facilitated the rapid agglomeration of fine particles. The agglomeration effect of the composite surfactant system was found to be superior to that of a single surfactant. XPS testing demonstrated a reduction in carbon content, which decreased to 79.43%, while oxygen content increased to 18.15% due to the treatment with the compound surfactant. Furthermore, FTIR analysis indicated that the complex surfactant system significantly increased the hydroxyl content of the coal samples, thereby enhancing the surface adsorption effect. In summary, the synergistic effect generated by the anionic-nonionic complex surfactants can markedly improve the hydrophilicity of anthracite, providing an effective approach for optimizing its wettability.