Study on the adsorption and dust suppression mechanism of urease-producing bacteria on coal dust

Abstract

Microbial dust suppressants are currently receiving extensive research attention, as they provide an efficient and low-environmental impact approach to dust suppression. The adsorption of urease-producing bacteria on coal dust is a key factor in the action of microbial dust suppressants, determining the release of urease and enhancing dust consolidation performance. However, to date, few studies have been carried out on this and therefore, the dust suppression mechanism of microbial dust suppressants remains unclear. In order to comprehensively explore the dust suppression mechanism of microbial dust suppressants, the adsorption characteristics and mechanism of interaction between coal dust and the urease-producing bacterial strain Bacillus X4 ( B. X4) were studied. In addition, the relationship between adsorption performance and dust suppression efficiency was determined. It was found that the adsorption capacity of B. X4 bacteria was the highest for 40–80 mesh coal (40.71 mg/g), exhibiting a 1.61-fold greater adsorption affinity that for 120–200 mesh coal dust. Scanning electron microscopy (SEM) and adsorption isotherms showed that large quantities of bacteria could be adsorbed on the surface of coal dust, with bacteria adhering via monolayer adsorption. Fourier transform infrared (FTIR) spectroscopy analysis showed that the amide group on the surface of bacteria was the main active group for bacterial adsorption to coal dust. The results of contact angle measurements and molecular dynamic simulations demonstrated that B. X4 bacteria improved the wettability of water on the surface of coal dust. Furthermore, larger coal dust particle sizes resulted in a higher content of calcium carbonate being produced after spraying the microbial dust suppressant. The microbial dust suppressant achieved the best dust suppression performance when sprayed on 40–80 mesh coal dust, which was consistent with the adsorption analysis results, indicating that the adsorbed amount of microorganisms on coal dust was positively correlated with the dust suppression effect. • Urease-producing bacteria formed a monolayer on coal dust with uneven adsorption. • Adsorption mainly involved amide groups on the urease-producing bacteria surface. • Dust suppression was positively correlated with bacterial adsorption on coal dust.