Theses and Dissertations at Montana State University (MSU)
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Item Material properties of ureolytically induced calcium carbonate adhesives(Montana State University - Bozeman, College of Engineering, 2023) Anjum, Sobia; Chairperson, Graduate Committee: Robin Gerlach; This is a manuscript style paper that includes co-authored chapters.Polymers used in adhesive applications are often petrochemical-based and release volatile organic compounds (VOCs) during application. These VOCs can accumulate indoors to the detriment of human health. Biopolymers potentially offer a non-toxic and sustainable alternative to synthetic polymers but generally have limited physical stability and low mechanical performance. One of the methods of improving the stability and adhesive performance of biopolymers is the addition of a mineral phase to reinforce biopolymer adhesives. In this work, biomineral-reinforced biopolymer adhesives were produced by ureolytically induced precipitation of calcium carbonate in the presence of guar gum and soy protein. The microbially and enzymatically induced ureolysis was carried out by the ureolytic bacterium, Sporosarcina pasteurii, or by jack bean urease. The resulting adhesives were referred to as ureolytically induced calcium carbonate precipitation (UICP)-reinforced adhesives and specifically microbially and enzymatically induced calcium carbonate (MICP and EICP)- reinforced adhesives. The adhesive strength of these composite adhesives was optimized by varying calcium and cell (or enzyme) concentrations. The adhesive strength of biomineral reinforced guar gum and soy protein biopolymers was up to 2.5 and 6 times higher than the adhesive strength of the biopolymers alone, respectively. The durability of the MICP-reinforced adhesives was tested after varying immersions (24 h and 7 days), relative humidities (50 and 80% RH), and temperatures (-20, 100, and 300?C). The durability of the MICP-reinforced adhesives, upon immersion, was significantly improved compared to biopolymer alone, and maintained their adhesive strength at moderate humidities and from below-freezing to room temperatures after 7- day exposures. To determine the effect of biopolymers on the nanoscale material properties of biomineral aggregates, enzymatically induced calcium carbonate precipitation was induced in the presence of a standard protein, Bovine Serum Albumin (BSA). Nanoindentation and Atomic Force Microscopy show that the moduli of the mineral precipitates were significantly lowered in the presence of BSA. Atomic force microscopy also showed that BSA introduced structural variations and moduli gradation in biominerals. These results demonstrate that the presence of a protein additive, specifically BSA, can alter the nanoscale structure and material properties of calcium carbonate precipitates. Using an organic additive to manipulate microscale material properties of biominerals offers possibilities for advanced control at the microscale and enhanced toughness at the macroscale for engineering applications such as in construction, binder, and adhesive applications.Item Comparing the mechanical properties of shale cores: intact vs. fractured and sealed with UICP(Montana State University - Bozeman, College of Engineering, 2023) Bedey, Kayla Marjorie; Chairperson, Graduate Committee: Catherine Kirkland; This is a manuscript style paper that includes co-authored chapters.Fractures in subsurface shale formations are instrumental in the recovery of hydrocarbon resources. A result of hydraulic fracturing, these fractures have the potential to become harmful leakage pathways that may contribute undesired fluids to the atmosphere and functional groundwater aquifers. Ureolysis-induced calcium carbonate precipitation (UICP) is a biomineral solution where the urease enzyme converts urea and calcium into calcium carbonate mineral. The resulting biomineral can bridge gaps in fractured shale, reduce undesired fluid flow through leakage pathways, limit fracture propagation, better store carbon dioxide, and potentially extend the efficiency of future and existing wells. The mechanical properties of fractured shale sealed with UICP was investigated using a modified Brazilian indirect tensile strength test. Part one of this study investigated the tensile strength of shale rock using intact Eagle Ford (EF) and Wolfcamp (WC) shale cores (5.08 cm long by 2.54 cm diameter) tested at room temperature (RT) and 60°C. Results show no significant difference between shale types (average tensile strength = 6.19 MPa). EF cores displayed a higher strength at RT versus 60°C, but no difference was seen between temperatures for WC cores. Part two used UICP to seal shale cores (5.08 cm long by 2.54 cm diameter) with a single, heterogeneous fracture spanning the core length. UICP was delivered two ways: 1) the flow-through method injected 20-30 sequential patterns of microbes and UICP-promoting fluids into the fracture until fracture permeability reduced by three orders of magnitude and 2) the immersion method placed cores treated with guar gum and UICP-promoting solutions into a batch reactor, demonstrating that guar gum is a suitable inclusion to UICP-technology and may be capable of reducing the number of injections required in flow-through methodology. Tensile results for both flow-through and immersion methods were widely variable (0.15 - 8 MPa), and in some cores the biomineralized fracture split apart. Notably in other cores the biomineralized fracture remained intact, demonstrating more cohesion than the surrounding shale, indicating that UICP may produce a strong seal for subsurface application.Item Improving pH and temperature stability of urease for ureolysis-induced calcium carbonate precipitation(Montana State University - Bozeman, College of Engineering, 2022) Akyel, Arda; Chairperson, Graduate Committee: Robin Gerlach and Adrienne Phillips (co-chair); This is a manuscript style paper that includes co-authored chapters.Ureolysis-induced calcium carbonate (CaCO 3) precipitation (UICP) is a promising technology that takes advantage of urea hydrolysis. During UICP, the enzyme urease hydrolyzes urea, and calcium carbonate can precipitate in the presence of calcium (Ca 2+). This process is also known as biomineralization, and urease is found in several bacterial and plant cells. Urease must be active to enable biomineralization engineering applications such as sealing leakage pathways around wells for CO 2 sequestration. However, biotechnological reactions are limited by physicochemical conditions (temperature, pH, toxic compounds, etc.), and conditions in practice can be suboptimal. Sporosarcina pasteurii and jack bean meal (JBM) ureolytic activities were investigated while simulating potential environmental stresses such as high temperature and pH conditions. Urease was extracted from bacterial cells to evaluate bacterial urease as an alternative to plantbased ureases. Ureolytic activities and thermal inactivation for both bacterial- and plant-based ureases were similar. Urease became thermally inactivated at elevated temperatures (> 50 °C), and urease activity also decreased when pH values moved away from circumneutral pH conditions, i.e., at pH values < 5 and > 9. Urease stability was improved through immobilization for temperatures up to 60 °C and pH values between 3.7 and 4.7. While suspended urease did not demonstrate any residual activity after a one-hour exposure to pH 4.1 at 60 °C, immobilized urease remained active after the exposure. The studies presented here suggest that UICP technology may be used in a broad range of applications, and urease stability can be improved. The use of bacterially derived urease could be cost-competitive. UICP technology not only has the potential to solve various engineering challenges, but it also has the potential to replace traditional cement technologies and contribute to a more sustainable future.Item A study of bio-mineralization for the application of reducing leakage potential of geologically stored CO 2(Montana State University - Bozeman, College of Engineering, 2019) Daily, Ryanne Leigh; Chairperson, Graduate Committee: Adrienne PhillipsA primary concern of carbon capture and storage (CCS) is leakage of the stored carbon dioxide (CO 2) from the subsurface back to the surface. To ensure long term storage of the CO 2, mitigation strategies are being developed to seal high permeability regions, such as fractures present in the caprock or the near wellbore environment. Ureolysis induced calcium carbonate precipitation (UICP) is a widely investigated technology utilizing the enzymatically driven process of ureolysis to alter the properties of porous media. The advantage of this technology over traditional fracture sealing methods, such as well cement, is the use of low-viscosity aqueous fluids enabling access to smaller fractures. However, CCS reservoirs provide a problematic environment for microbial activity due to the acidity of dissolved CO 2, high pressures, and elevated temperatures. A flow-through pressurized reactor experiment and batch high-pressure ureolysis rate experiments were conducted to investigate the application of UICP technology to mitigate CO 2 migration. First, UICP was induced in two composite rock cores in an environment simulating a CCS reservoir, using a high-pressure axial flow reactor, with an initial and final exposure of the rock cores to a carbonated brine. As a result of UICP, the apparent permeability of the rock cores were reduced by 5-orders of magnitude. The CO 2 challenge increased apparent permeability by 4-orders of magnitude, likely due to a preferential flow path created through the calcium carbonate (CaCO 3) seal, which was found with X-ray microcomputed tomography (micro-CT) imaging. The porosity of the composite rock cores was assessed throughout the experiment with two non-invasive technologies, micro-CT and nuclear magnetic resonance (NMR), both reported a significant decrease in porosity due to UICP and a slight increase after the CO 2 exposure. Second, ureolysis kinetics were assessed in the presence of a pressurized carbonated brine at pressures between 0 and 4 MPa. The kinetic studies were performed in a high-pressure batch reactor connected to high-pressure pH and conductivity probes. Samples could not be taken from the batch reactor without losing pressure; thus, conductivity was used as a surrogate measurement for urea concentration. It was found that, for the pressures tested, JBM urease was capable of hydrolyzing urea in the presence of a pressurized carbonated brine. It was also hypothesized that the rate observed at each experimental pressure may have been dependent on the buffered pH of the system. The combination of these studies suggests that, if the challenge of dissolution could be overcome, bio-mineralization may be used to enhance CCS by reducing the permeability of CO 2 leakage pathways.Item Reactive transport in biofouled and biomineralized porous media(Montana State University - Bozeman, College of Engineering, 2010) Schultz, Logan Nicholas; Chairperson, Graduate Committee: Robin GerlachThe geologic subsurface environment contains regions of high porosity where fluid flows both naturally and during engineered technologies such as carbon sequestration, enhanced oil recovery, and bioremediation of contaminants. In these porous media regions, microbes can have both desirable and undesirable effects on the hydrodynamics and fluid chemistry by inducing the formation of microbial aggregates, which can include extracellular polymeric substance and abiotic particles such as mineral precipitates. While not the focus of this research, these analyses are likewise applicable to biomatter control scenarios in filtration systems and other industrial reactors with a high surface area to volume ratio. Microbially-induced ureolytic calcium carbonate precipitation has been suggested as a means to mitigate leakage from geologic CO 2 sequestration sites and as a means to immobilize divalent contaminants such as strontium-90 in remediation scenarios. In this process, microbes hydrolyze urea, increasing the solution pH, generating carbonate ions, and ultimately shifting the saturation state of the fluid and leading to solid calcium carbonate (CaCO 3) formation in a calcium-rich environment. Experiments were conducted to assess the distribution and effects of biofouling and biomineralization in two-dimensional flat plate reactors with 1mm pore spaces simulating a tortuous porous media environment. In biomineralization experiments, calcium carbonate was formed under flow conditions, and strontium was effectively immobilized within the crystal lattice, suggesting the applicability of subsurface biotechnical applications utilizing this technology. Image, residence time distribution, and piezometer analyses of biofouling experiments quantified porosity and hydraulic conductivity reductions. Biofilms were grown under constant flow and head conditions and were shown to be more channeled and evenly distributed along the flow path in constant flow conditions. Biofilms were challenged with chlorinated bleach, which temporarily increased the hydraulic conductivity, yet failed to remove significant biofouling unless coupled with significant fluid shear. In situ methods utilizing stereo and confocal microscopy were developed to visualize and quantify the distribution of biomatter formation and analyze the biological environment at the surface of bio-induced minerals.