Batch preparation in lab-scale and performance study of biological calcium carbonate (CaCO3)

Microbial induced calcium carbonate precipitation (MICP) has attracted considerable attention as an environmentally friendly method for the preparation of CaCO 3 . In this paper, the microorganism producing carbonic anhydrase (CA) was selected to prepare biological CaCO 3 , and a 30 L reactor was constructed to enable batch preparation at the laboratory scale. Subsequently, the key influencing factors in the preparation process of biological CaCO 3 were studied based on enzyme activity and Michaelis-Menten equation, and the performances of biological CaCO 3 were explored through various characterization methods. Finally, the preparation mechanism of biological CaCO 3 was revealed. The results of reaction kinetics induced by CA indicated that the Michaelis constant ( K m ) during the formation of biological CaCO 3 was 4.438 mM, and the reaction rate ( V max ) when CA was saturated with substrate was 1.737 mM·h −1 . Moreover, the hydration reaction of CO 2 catalyzed by CA was the key influencing factor in the formation process of biological CaCO 3 . Various test results showed that calcite biological CaCO 3 had a porous structure with a particle size distribution of 3–8 μm, a specific surface area of 83.19 m 2 /g, and an adhesion force of 829 nN. Meanwhile, the microorganism acted as nucleation sites, promoting the nucleation and crystal growth of biological CaCO 3 . In general, this paper provides a new method and approach for the batch preparation of biological CaCO 3 , which is beneficial for advancing its preparation and application in the future