Montmorillonite combined with microbially induced carbonate precipitation for wind erosion control of bare surface soil in arid mining area

Open-pit mining will form a large area of bare soil. Under the dry and windy climate in northern China, the surface bare soil of mining area is prone to wind erosion and dust, posing a threat to the environment and human health. This study evaluated the performance of montmorillonite combined with microbially induced carbonate precipitation (MICP-M) to control bare soil wind erosion in mining area. Results showed that the average CaCO3 contents, surface strength, threshold friction velocity (TFV) and thickness of soil crust was the highest, and the mass loss was the lowest in MICP-M group, which significantly improved the wind erosion resistance. After MICP-M solidified the bare soil, the pH value only slightly increased. The consolidation layer could effectively lock in soil moisture, maintain a certain degree of permeability, and had good environmental application performance. Field emission scanning electron microscope (FESEM) tests with energy dispersive X-ray (EDX) and X-ray diffraction (XRD) confirmed more calcite appeared in the soil treated with MICP-M. Ultra-depth three-dimensional maps and particle size analysis indicated that biological bridging was the main consolidation mechanism. The above results indicate that MICP-M has great potential as a wind erosion mitigation strategy.