scholarly journals Microbial-induced calcium carbonate precipitation: an experimental toolbox for in situ and real time investigation of micro-scale pH evolution

RSC Advances ◽  
2020 ◽  
Vol 10 (35) ◽  
pp. 20485-20493
Author(s):  
Jennifer Zehner ◽  
Anja Røyne ◽  
Alexander Wentzel ◽  
Pawel Sikorski
Keyword(s):  
Calcium Carbonate ◽  
Real Time ◽  
Experimental Methods ◽  
Carbonate Precipitation ◽  
Calcium Carbonate Precipitation ◽  
Micro Scale ◽  
Ph Changes ◽  
Global And Local ◽  
Local Ph

We present two novel experimental methods to follow global and local pH changes on a microscale in bio-cementation processes.

scholarly journals Microbial-induced calcium carbonate precipitation: An experimental toolbox for in situ and real-time investigation of micro-scale pH evolution

2020 ◽  
Author(s):  
Jennifer Zehner ◽  
Anja Røyne ◽  
Alexander Wentzel ◽  
Pawel Sikorski
Keyword(s):  
Calcium Carbonate ◽  
Real Time ◽  
Small Sample ◽  
Carbonate Precipitation ◽  
Calcium Carbonate Precipitation ◽  
Micro Scale ◽  
Ph Changes ◽  
Macro Scale ◽  
Local Ph

AbstractConcrete is the second most consumed product by humans, after water. However, the production of cement, which is used as a binding material in concrete, causes more than 5% of anthropogenic CO2 emissions and has therefore a significant contribution to climate change and global warming. Due to increasing environmental awareness and international climate goals, there is a need for emission-reduced materials, that can replace conventional concrete in certain applications. One path to produce a solid, concrete-like construction material is microbial-induced calcium carbonate precipitation (MICP). As a calcium source in MICP, crushed limestone, which mainly consists out of CaCO3, can be dissolved with acids, for example lactic acid. The pH evolution during crystallization and dissolution processes provides important information about kinetics of the reactions. However, previous research on MICP has mainly been focused on macro-scale pH evolution and on characterization of the finished material. To get a better understanding of MICP it is important to be able to follow also local pH changes in a sample. In this work we present a new method to study processes of MICP at micro-scale in situ and in real time. We present two different methods to monitor the pH changes during the precipitation process of CaCO3. In the first method, the average pHs of small sample volumes are measured in real time, and pH changes are subsequently correlated with processes in the sample by comparing to optical microscope results. The second method is introduced to follow local pH changes at a grain scale in situ and in real time. Furthermore, local pH changes during the dissolution of CaCO3 crystals are monitored. We demonstrate that these two methods are powerful tools to investigate pH changes for both MICP precipitation and CaCO3 dissolution for knowledge-based improvement of MICP-based material properties.Graphical TOC Entry

scholarly journals Real-time monitoring of calcification process by Sporosarcina pasteurii biofilm

The Analyst ◽  
2016 ◽  
Vol 141 (10) ◽  
pp. 2887-2895 ◽  
Author(s):  
Dustin Harris ◽  
Jyothir Ganesh Ummadi ◽  
Andrew R. Thurber ◽  
Yvan Allau ◽  
Circe Verba ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Real Time ◽  
Carbonate Precipitation ◽  
Real Time Monitoring ◽  
Calcium Carbonate Precipitation ◽  
Sporosarcina Pasteurii ◽  
Scanning Electrochemical Microscope ◽  
Calcification Process

Chemical and morphological mapping of live bacterial assisted calcium carbonate precipitation using scanning electrochemical microscope (SECM).

scholarly journals A sample cell for the study of enzyme-induced carbonate precipitation at the grain-scale and its implications for biocementation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jennifer Zehner ◽  
Anja Røyne ◽  
Pawel Sikorski
Keyword(s):  
Real Time ◽  
Laser Scanning Microscopy ◽  
In Situ Monitoring ◽  
Confocal Laser ◽  
Precipitation Process ◽  
Successful Implementation ◽  
Detailed Knowledge ◽  
Carbonate Precipitation ◽  
Sample Cell

AbstractBiocementation is commonly based on microbial-induced carbonate precipitation (MICP) or enzyme-induced carbonate precipitation (EICP), where biomineralization of $$\text {CaCO}_{3}$$ CaCO 3 in a granular medium is used to produce a sustainable, consolidated porous material. The successful implementation of biocementation in large-scale applications requires detailed knowledge about the micro-scale processes of $$\text {CaCO}_{3}$$ CaCO 3 precipitation and grain consolidation. For this purpose, we present a microscopy sample cell that enables real time and in situ observations of the precipitation of $$\text {CaCO}_{3}$$ CaCO 3 in the presence of sand grains and calcite seeds. In this study, the sample cell is used in combination with confocal laser scanning microscopy (CLSM) which allows the monitoring in situ of local pH during the reaction. The sample cell can be disassembled at the end of the experiment, so that the precipitated crystals can be characterized with Raman microspectroscopy and scanning electron microscopy (SEM) without disturbing the sample. The combination of the real time and in situ monitoring of the precipitation process with the possibility to characterize the precipitated crystals without further sample processing, offers a powerful tool for knowledge-based improvements of biocementation.

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