In-situ synergistic mechanism of wetting and biomineralization in a polymeric surfactant-based microbial composite dust suppressant for dust control in open-pit mines.

Open-pit coal mining produces massive coal dust and has intensified dust pollution. Chemical suppressants have short retention times and poor consolidation, while microbial-induced carbonate precipitation (MICP) provides long-term consolidation, a mismatch between rapid moisture loss and slow biomineralization creates a persistent "dust suppression gap." To address these issues, this study developed a novel chemical-microbial composite dust suppressant by integrating sodium starch octenyl succinate (SSOS, a polymeric surfactant), sodium dodecyl benzene sulfonate (SDBS), and centrifuged Sporosarcina pasteurii cells, realizing in-situ synergy between wetting and biomineralization. The SSOS/SDBS composite reduces surface tension to 27.15 mN/m, increases oxygen-containing groups on coal surfaces (66.97% O content), and enhances moisture retention. SSOS enhances dust adsorption and regulates calcium carbonate crystallization during MICP by coordinating Ca2+ and CO32-, promoting uniform calcite growth that favors the (104) crystal plane and enabling in situ coordination between chemical suppression and microbial consolidation. Compared to conventional microbial methods, treated dust shows 59.3% hardness increase, 674.4% aggregate size growth, and ultra-low porosity (0.00051 cm3/g), significantly enhancing wind erosion resistance. Quantum chemical calculations and molecular dynamics simulations revealed SSOS forms ternary complexes with Ca2+ and HCO3- (extending nucleation induction) and its amphiphilic structure enhances water retention (hydrophilic backbone via hydrogen bonding) and film durability (hydrophobic chains). This study proposes a "rapid wetting-long-term consolidation" strategy, integrating polymeric surfactants with MICP for efficient, sustainable dust control in open-pit mines.