Preparation and properties of microcapsule dust suppressant based on corn straw biochar and guar gum

To address dust pollution in coal mines and overcome the drawbacks of traditional chemical dust suppressants, such as strong environmental dependence, high ecological toxicity and susceptibility to secondary pollution, a novel eco-friendly microcapsule dust suppressant was prepared via microencapsulation technology. Using guar gum as the main wall material and corn straw biochar as the core material, the preparation adopted the emulsification-coacervation method combined with stearic acid hydrophobic modification and citric acid crosslinking treatment. The microcapsules feature a compact surface structure and favorable interfacial bonding. The corn straw biochar core possesses well-developed porous structures and a high specific surface area, enabling efficient adsorption of moisture and dust particles. The guar gum wall material forms a three-dimensional gel network after crosslinking with citric acid, which endows the product with excellent wind erosion resistance and sustained-release performance. Test results show that the microcapsule dust suppressant exhibits remarkably better wind erosion resistance than conventional methods including water sprinkling and sodium dodecylbenzene sulfonate dust suppression, with a maximum wind erosion mass loss rate of only 8%. The dust suppression efficiencies for total dust and respirable dust reach 90.6% and 83.4% respectively, more than twice those of traditional water sprinkling. The 28-day biodegradation rate of the microcapsule product is 64.3%, demonstrating favorable eco-friendliness and compliance with environmental standards. Field tests show that its water consumption is merely 20% of that of conventional water sprinkling, with the overall cost reduced by 22%, and the dust suppression duration extended to over 12 hours. Relying on the adsorption of porous core material, barrier protection of wall material and environment-responsive release mechanism, and this technology establishes a three-way synergistic dust suppression system of “moisture absorption-consolidation-barrier”. It integrates long-term dust suppression performance and environmental friendliness, and realizes the organic combination of high-efficiency dust control and green development. This work provides an innovative, economical and sustainable solution for dust treatment in coal mines and other complex working environments.