Mineralization Mechanism of Mineralization Bacteria on Strontium Crystallization of Simulated Radionuclides

Abstract

Microbial‐induced carbonate crystallization is a natural biological process in which microbes produce inorganic materials as part of their basic metabolic activities. Herein, the influence of the bacterial somatic solution and secretion solution on the crystal growth behavior of strontium carbonate (SrCO3) is studied. The mineralization mechanism of carbonate mineralizing bacteria on simulated radionuclides (Sr2+) is also demonstrated. The results reveal that the morphology of SrCO3 crystal formed by involvement of microbes is greatly different with chemical method, which means that microbes play a critical role during the SrCO3 crystallization process. Briefly, bacterial somatic provides nucleation sites for SrCO3 during both the nucleation and growth processes. In addition, bacterial secretions play a vital role in regulating the morphology of mineralized products. This work unveils the mineralization process of strontium nuclides, providing reference for the control of crystal morphologies and structural properties of the SrCO3.

Effect of Divalent Cations (Cu, Zn, Pb, Cd, and Sr) on Microbially Induced Calcium Carbonate Precipitation and Mineralogical Properties

“…Unlike divalent cationic heavy metals, Sr, a radioactive element, is known to effectively sequester carbonate minerals because of its chemical similarity to calcium (Achal et al, 2012;Kang et al, 2014a;Tian et al, 2020). In this experiment, the precipitation of carbonates by S. pasteurii KCTC 3558was induced by varying the concentrations of Sr from 1 to 30 mM.…”

“…According to the recent study, bacterial somatic structure provides nucleation sites for SrCO 3 during nucleation and growth. Also, bacterial secretions play a vital role in regulating the morphology of mineralized products (Tian et al, 2020). Therefore, in a medium containing both Sr and Ca, Sr is co-precipitated in calcium carbonate when the ratio of Sr/Ca is less than 1.…”

“…In particular, Cd was found to inhibit microbial growth at concentrations of 0.5 mM or higher. Unlike other divalent heavy metals, Sr, a radioactive element, was sequestered as carbonate minerals via MICP when it is present in high concentration due to its chemical similarity with Ca in terms of oxidation state, ionic radius, and solubility product (Goldschmidt, 1954;Achal et al, 2012., Kang et al, 2014aTian et al, 2020).…”