Denitrification induced calcium carbonate precipitation by indigenous microorganisms in coal seam and its application potential in CO2 geological storage

Carbon capture, utilization and storage (CCUS) is an effective means to achieve dual carbon goals. However, the leakage of CO2 is a considerable risk. In this work, a new method was proposed to reduce the leakage of CO2 in coal seam by denitrification induced carbonate precipitation (DICP) using indigenous microorganisms (IM). After enrichment and optimization, the mineralization efficiency of IM reached 90.47% and Pseudomonas was dominated. The degradation of negatively charged groups in extracellular polymeric substances (EPS), especially carboxyl, was essential to the formation of CaCO3. The mineralization efficiency even increased under the presence of coal while the pore development was significantly reduced by the formed bio-minerals. The microflora was proven to resist the negative effects of CO2 on bacterial growth and metabolism. Then, a conceptual model of industrial application was proposed. Our results demonstrated the good application potential of DICP technology in coal seam CO2 geological storage.