Composite surface modification of layered double hydroxides for improved powder flowability and aerosol transport in coal-fire inhibition

The severe aggregation of ultrafine layered double hydroxide (LDH) particles limits their powder flowability and aerosol transport, thereby restricting their application in aerosol‑based coal fire prevention. In this work, an APTES–succinic anhydride (3‑Aminopropyltriethoxysilane, SA) co‑modification strategy was developed to regulate the interfacial properties of LDHs. Experimental characterization combined with molecular dynamics simulations was employed to investigate the effects of surface modification on particle dispersion, aerosol transport, and coal spontaneous combustion inhibition. Results show that co‑modification forms an organic interfacial layer that effectively suppresses particle aggregation. Compared with raw samples, the median particle size (D50) decreases by 29.26%, and basic flow energy reduces by 24.31%. Aerosol deposition uniformity improves, with mass at the farthest collection point increasing by 13.41%. The ignition temperature of coal treated with AS-LDHs was 13.37 °C higher than that of coal treated with LDHs, and the maximum temperature differential across monitoring points dropped by 30.09%. Simulations suggest steric repulsion between modified interfaces and reduced local oxygen accessibility. This study establishes a multi‑scale mechanism linking interfacial regulation, aggregation suppression, aerosol transport and coal fire inhibition.