Modified one-phase-low-pH EICP method using low-pH cementation solution for soil biomineralization.
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| Title: | Modified one-phase-low-pH EICP method using low-pH cementation solution for soil biomineralization. |
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| Authors: | Chen, Yi-Wei1,2 (AUTHOR), Cui, Ming-Juan3 (AUTHOR) cuimj@fzu.edu.cn, Lai, Han-Jiang1,2 (AUTHOR) laihj2021@163.com, Zheng, Jun-Jie4 (AUTHOR), Ren, Yu-Xiao5 (AUTHOR) |
| Source: | Acta Geotechnica. Aug2025, Vol. 20 Issue 8, p4133-4146. 14p. |
| Subjects: | Biomineralization, Urease, Cementation (Petrology), Soil stabilization, Soil remediation, Calcium carbonate |
| Abstract: | One-phase-low-pH method is a simple, efficient and easy-to-use biogrouting method for biomineralization based on an Enzyme Induced Carbonate Precipitation (EICP) process. This method utilizes the low-pH biotreatment solution (a mixture of urease solution and cementation solution) to provide a lag period for the biomineralization process, allowing the biotreatment solution to be uniformly distributed within the soil and thereby improving the uniform distribution of calcium carbonate. The existing one-phase-low-pH method uses a low pH urease solution to prepare the biotreatment solution. However, long-term exposure to a low pH environment may result in a decrease in activity or even inactivation of urease, which is not conducive to the practical application of this technology. In this study, a modified one-phase-low-pH method using low pH cementation solution is proposed. Three sets of tests, including urease activity durability tests, solution tests, and sand column treatment tests, were conducted in this study to clarify the necessity and feasibility of the modified method. The test results showed that the acidic environment accelerated the decrease of urease activity over time. This phenomenon would be more pronounced at a lower pH, and urease would be immediately inactive at a pH lower than 4.5. Meanwhile, a high chemical concentration would also lead to a decrease in activity or even inactivation of urease. If urease is active and the initial pH of the biotreatment solution is higher than 4.5, the pH of the biotreatment solution will rapidly rise to a weakly alkaline state and enzyme-induced carbonate precipitation can occur. A biotreatment solution that would produce relatively uniform biomineralization can be prepared by using cementation solution with a pH range of 1.25–3.5 and bacterial urease solution in a volume ratio of 1:1. For the sand column with relatively uniform biomineralization, the pH of the cementation solution (or the initial pH of the biotreatment solution) has a negligible effect on the strength enhancement for similar calcium carbonate content. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | One-phase-low-pH method is a simple, efficient and easy-to-use biogrouting method for biomineralization based on an Enzyme Induced Carbonate Precipitation (EICP) process. This method utilizes the low-pH biotreatment solution (a mixture of urease solution and cementation solution) to provide a lag period for the biomineralization process, allowing the biotreatment solution to be uniformly distributed within the soil and thereby improving the uniform distribution of calcium carbonate. The existing one-phase-low-pH method uses a low pH urease solution to prepare the biotreatment solution. However, long-term exposure to a low pH environment may result in a decrease in activity or even inactivation of urease, which is not conducive to the practical application of this technology. In this study, a modified one-phase-low-pH method using low pH cementation solution is proposed. Three sets of tests, including urease activity durability tests, solution tests, and sand column treatment tests, were conducted in this study to clarify the necessity and feasibility of the modified method. The test results showed that the acidic environment accelerated the decrease of urease activity over time. This phenomenon would be more pronounced at a lower pH, and urease would be immediately inactive at a pH lower than 4.5. Meanwhile, a high chemical concentration would also lead to a decrease in activity or even inactivation of urease. If urease is active and the initial pH of the biotreatment solution is higher than 4.5, the pH of the biotreatment solution will rapidly rise to a weakly alkaline state and enzyme-induced carbonate precipitation can occur. A biotreatment solution that would produce relatively uniform biomineralization can be prepared by using cementation solution with a pH range of 1.25–3.5 and bacterial urease solution in a volume ratio of 1:1. For the sand column with relatively uniform biomineralization, the pH of the cementation solution (or the initial pH of the biotreatment solution) has a negligible effect on the strength enhancement for similar calcium carbonate content. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 18611125 |
| DOI: | 10.1007/s11440-025-02625-8 |
