From surfactant headgroup regulated hygroscopicity to enhanced interfacial water stability: New insights into durable suppression of respirable coal dust in coal mining

Interfacial water stabilization suppresses coal dust resuspension. • Hydrophilic headgroups govern the stability of coal dust interfacial water. • Sulfonate headgroups stabilize bound water and interfacial H-bond networks. • Mono- and multilayer water retention reduces ultrafine coal dust release. Interfacial water stability governs the durability of water-based suppression for respirable coal mine dust (RCMD), but its regulation by surfactant headgroup structure remains insufficiently understood. This study used underground deposited coal dust associated with respirable dust release and selected three dodecyl anionic surfactants with different hydrophilic headgroups to clarify how headgroup-regulated particle hygroscopicity affects interfacial water retention and dust release resistance. The results showed that surfactant treatment increased coal dust surface polarity and strengthened coal-water interactions, promoted water vapor adsorption and moisture retention. This process was affected by particle size, relative humidity, and temperature. Sodium dodecyl sulfonate (SDS) exhibited the strongest hygroscopic stability, the equilibrium moisture uptake increasing by 6.36% compared with raw dust. The modified samples retained a mesopore dominated pore structure, while smoother pore walls favored water migration. In the wind erosion test, SDS treated coal dust showed the highest wind erosion resistance at 8 h (86.06%), and its D50 increased to 2.178 times that of raw dust, indicating inhibited preferential release of ultrafine particles. Simulations showed that the sulfonate headgroup increased the peak net isosteric heat of adsorption to 20.25 kJ/mol, strengthened electrostatically dominated coal-water interactions, and stabilized the hydrogen bond network. Engineering verification further confirmed that SDS assisted spraying more effectively reduced respirable dust in high disturbance zones. These findings provide a scientific basis for supporting safer and cleaner industrial operations. Download: Download high-res image (281KB) Download: Download full-size image