Microbially/CO₂-derived CaCO₃ cement and its microstructural and mechanical performance

Abstract

Compared with the production of ordinary Portland cement (OPC) with large carbon emissions, biological carbon sequestration to prepare low-carbon cement can effectively decrease carbon dioxide (CO₂) emissions, which can reduce the greenhouse effect, thereby reducing the frequency and intensity of climate disasters. Carbon-capturing bacteria (CCB) can capture atmospheric CO₂ and convert it into bicarbonate ions, which can be combined with calcium ions to form CaCO₃ cement that can partially replace OPC for dust control. This study compared the ability of two CCBs (Paenibacillus mucilaginosus and Streptomyces microflavus ) to capture CO₂. The biomineralization efficiency of CaCO₃ for P. mucilaginosus (39.34%) was much higher than that for S. microflavus (7.38%) in a Ca(NO₃)₂ solution in the concrete-curing room environment. The decomposition temperature of the CaCO₃ crystals in DI was slightly higher than that of P. mucilaginosus and significantly higher than that of S. microflavus. When the spraying time was equal to three, 10% carbide sludge (CS) content was optimal according to the surface hardness (HD) of the consolidation layer of the sand samples. The CaCO₃ mineralized by CCBs can be used to consolidate desert sand and dust in practical engineering applications.

Keywords:

• carbon dioxide
• carbon-capturing bacteria
• calcium carbonate
• decomposition temperature
• consolidation layer

Disclosure statement

The authors declare no conflict of interest.

Author contribution

XN collected, reviewed, and wrote the manuscript. QY contributed to conceive and revise the manuscript.

Data availability statement

The datasets and materials used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

The research described in this paper was financially supported by the Opening Funds of Jiangsu Key Laboratory of Construction Materials (grant No. CM2018-02) and the National Natural Science Foundation of China (Grant Nos. 51702238 and 52108300). Their financial support is gratefully acknowledged.