Optimization of one-phase-low-pH enzyme-induced carbonate precipitation method for soil improvement

There are two major challenges for the use of enzyme-induced carbonate precipitation (EICP)-based soil improvement method: cost and treatment effect. Optimizing the parameters of the treatment solution is one way to enhance the treatment effect and/or reduce the treatment cost. In this study, three...

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Main Authors: Cui, Ming-Juan, Chu, Jian, Lai, Han-Jiang
Other Authors: School of Civil and Environmental Engineering
Format: Article
Language:English
Published: 2024
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Online Access:https://hdl.handle.net/10356/176217
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-1762172024-05-17T15:33:29Z Optimization of one-phase-low-pH enzyme-induced carbonate precipitation method for soil improvement Cui, Ming-Juan Chu, Jian Lai, Han-Jiang School of Civil and Environmental Engineering Earth and Environmental Sciences Crude soybean enzyme Enzyme-induced carbonate precipitation There are two major challenges for the use of enzyme-induced carbonate precipitation (EICP)-based soil improvement method: cost and treatment effect. Optimizing the parameters of the treatment solution is one way to enhance the treatment effect and/or reduce the treatment cost. In this study, three key factors: the initial pH (i.e. pH0) of the enzyme solution used to prepare the treatment solution (i.e. the mixture of enzyme solution, CaCl2 and urea), the urease activity of the treatment solution and the concentration of cementation solution (i.e. CaCl2 and urea) are investigated. Crude soybean enzyme solution and the one-phase-low-pH injection method are adopted for the treatment of sand. The results show that the pH0 of the enzyme solution affects the urease activity of enzyme and thus the urease activity of the prepared treatment solution. It is discovered in this paper that there is a threshold pH value for the treatment solution. Only when the pH of the treatment solution is higher than the threshold pH value, calcium ions convert completely into calcium carbonate. There is also a threshold urease activity which is affected by the concentration of cementation solution, CCS. The optimal CCS is 1.0 M. When the CCS is higher than 1.75 M, the urease activity of soybean enzyme solution would be completely lost. These findings are important in guiding the application of EICP treatment using the crude soybean enzyme in real soil improvement projects. Ministry of Education (MOE) Ministry of National Development (MND) Submitted/Accepted version The authors would like to thank the financial support through Grant No. MOE2015-T2-2-142 provided by the Ministry of Education, Singapore, Grant No. SMI-2018-MA-02 by the Singapore Maritime Institute, Grant No. L2NICCFP2-2015-1 by the Singapore Ministry of National Development, and the support of Centre for Urban Solutions, Nanyang Technological University. The authors would also like to thank the supported by the National Natural Science Foundation of China (NSFC) (Grant No. 52178319, 52108307), Natural Science Foundation of Fujian Province, China (Grant No. 2022J05020, 2022J05127) and the Opening Fund of Key Laboratory of Geohazard Prevention of Hilly Mountains, Ministry of Natural Resources (Fujian Key Laboratory of Geohazard Prevention) (Grant No. FJKLGH2022K003). 2024-05-14T02:31:46Z 2024-05-14T02:31:46Z 2024 Journal Article Cui, M., Chu, J. & Lai, H. (2024). Optimization of one-phase-low-pH enzyme-induced carbonate precipitation method for soil improvement. Acta Geotechnica, 19(3), 1611-1625. https://dx.doi.org/10.1007/s11440-023-02175-x 1861-1125 https://hdl.handle.net/10356/176217 10.1007/s11440-023-02175-x 2-s2.0-85181203349 3 19 1611 1625 en MOE2015-T2-2-142 SMI-2018-MA-02 L2NICCFP2-2015-1 Acta Geotechnica © 2024 The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature. All rights reserved. This article may be downloaded for personal use only. Any other use requires prior permission of the copyright holder. The Version of Record is available online at http://doi.org/10.1007/s11440-023-02175-x. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Earth and Environmental Sciences
Crude soybean enzyme
Enzyme-induced carbonate precipitation
spellingShingle Earth and Environmental Sciences
Crude soybean enzyme
Enzyme-induced carbonate precipitation
Cui, Ming-Juan
Chu, Jian
Lai, Han-Jiang
Optimization of one-phase-low-pH enzyme-induced carbonate precipitation method for soil improvement
description There are two major challenges for the use of enzyme-induced carbonate precipitation (EICP)-based soil improvement method: cost and treatment effect. Optimizing the parameters of the treatment solution is one way to enhance the treatment effect and/or reduce the treatment cost. In this study, three key factors: the initial pH (i.e. pH0) of the enzyme solution used to prepare the treatment solution (i.e. the mixture of enzyme solution, CaCl2 and urea), the urease activity of the treatment solution and the concentration of cementation solution (i.e. CaCl2 and urea) are investigated. Crude soybean enzyme solution and the one-phase-low-pH injection method are adopted for the treatment of sand. The results show that the pH0 of the enzyme solution affects the urease activity of enzyme and thus the urease activity of the prepared treatment solution. It is discovered in this paper that there is a threshold pH value for the treatment solution. Only when the pH of the treatment solution is higher than the threshold pH value, calcium ions convert completely into calcium carbonate. There is also a threshold urease activity which is affected by the concentration of cementation solution, CCS. The optimal CCS is 1.0 M. When the CCS is higher than 1.75 M, the urease activity of soybean enzyme solution would be completely lost. These findings are important in guiding the application of EICP treatment using the crude soybean enzyme in real soil improvement projects.
author2 School of Civil and Environmental Engineering
author_facet School of Civil and Environmental Engineering
Cui, Ming-Juan
Chu, Jian
Lai, Han-Jiang
format Article
author Cui, Ming-Juan
Chu, Jian
Lai, Han-Jiang
author_sort Cui, Ming-Juan
title Optimization of one-phase-low-pH enzyme-induced carbonate precipitation method for soil improvement
title_short Optimization of one-phase-low-pH enzyme-induced carbonate precipitation method for soil improvement
title_full Optimization of one-phase-low-pH enzyme-induced carbonate precipitation method for soil improvement
title_fullStr Optimization of one-phase-low-pH enzyme-induced carbonate precipitation method for soil improvement
title_full_unstemmed Optimization of one-phase-low-pH enzyme-induced carbonate precipitation method for soil improvement
title_sort optimization of one-phase-low-ph enzyme-induced carbonate precipitation method for soil improvement
publishDate 2024
url https://hdl.handle.net/10356/176217
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