Experimental Study of Enzyme-Induced Carbonate Precipitation for High Temperature Applications by Controlling Enzyme Activity

Abstract

Biomineralization is a popular reinforcement technology, but which is rarely studied at high temperatures. Some potential application targets are high-temperature environments. So it's essential to study the feasibility of biomineralization at high temperatures. In this article, plant urease was selected as a cost-effective enzyme for enzyme-induced carbonate precipitation (EICP) at high temperatures. Urease activity and urease enzyme-induced carbonate precipitation were studied as a function of temperature, urease concentration, and N-(n-butyl)-thiophosphoric triamide (NBPT) addition. The effects of reaction time, number of perfusions, urease concentration, temperature, and NBPT addition on the curing efficiency of sand columns were studied by unconfined compressive strength tests and by determining the resulting concentration of CaCO₃. The results demonstrated that the urease could maintain a stable activity at temperatures below 65 °C. At temperatures higher than 65 °C, urease was gradually inactivated with increasing temperature, which would influence the yield of precipitation. However, increasing the urease concentration and the number of infusions could ensure the sand solidified with adequate CaCO₃. In addition, NBPT was proposed as a new way to control urease activity, which resulted in a high UCS of the sand columns formed at high temperatures. This paper bears out that sand solidification can be achieved at high temperatures using EICP and lays the foundation for future application of EICP at high temperatures.

Keywords:

• Enzyme induced carbonate precipitation
• urease activity
• N-(n-butyl)-thiophosphoric triamide
• high temperature
• sand solidification

Acknowledgments

The authors thank the valuable comments from the reviewers.

Ethical approval

This article does not contain any studies with human participants performed by any of the authors.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability statement

All data, models, and code generated or used during the study appear in the submitted article.

Author contributions

Hengxing Wang: Conceptualization, Methodology, Investigation, Writing – original draft. Linchang Miao: Supervision, Writing – review & editing. Xiaohao Sun: Supervision, Writing – review & editing. Linyu Wu: Investigation. Guangcai FAN: Investigation, Methodology. All authors read and approved the manuscript.

Additional information

Funding

This study was funded by the National Natural Science Foundation of China (grant number 52173248), Science and Technology Department of Ningxia (grant number 2020BFG02014), Fundamental Research Funds for the Central Universities (grant number 2242020R20025) and Transportation Department of Ningxia (grant number 202000173).