Effect of TiO2-NPs on microbial-induced calcite carbonate precipitation

As a dust suppression method, microbial-induced calcium carbonate precipitation technology based on urease-producing bacteria has been widely used on roads; however, due to their low CaCO3 yield, microbial dust suppressants are not used in mining areas. To further improve the dust suppression effect of microbial dust suppressants, a TiO2-NPs/microbial dust suppressant was developed by adding TiO2-NPs to the microbial dust suppressant. The results showed TiO2-NPs improved the bacteria growth and the urease activity. The best formula of microbial dust suppressant was determined to be mineralized bacteria liquid (OD600 = 1.7) and TiO2-NPs 0.06 g/L. The wind erosion resistance tests showed that the dust suppression effect of the TiO2-NPs/microbial dust suppressant was better than that of the group without TiO2-NPs. The formation of CaCO3 was verified by Fourier-transform infrared spectrometry (FTIR), Scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS) and Transmission electron microscopy-energy-dispersive X-ray spectroscopy (TEM-EDS). Xray diffraction (XRD) results showed that the crystal forms of the produced CaCO3 were calcite and vaterite. These results indicated that TiO2-NPs improved the dust inhibition effect of microbial dust suppressants.