Scholarship & Research
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/1
Browse
4 results
Search Results
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 Feasibility study for field-scale use of Ureolysis-Induced Calcite Precipitation (UICP) for roadbed improvement(Montana State University - Bozeman, College of Engineering, 2023) Dorian, Hudson Thomas; Chairperson, Graduate Committee: Mohammad Khosravi; Adrienne J. Phillips (co-chair); This is a manuscript style paper that includes co-authored chapters.A series of tests were conducted to evaluate the feasibility of using ureolysis-induced calcium carbonate precipitation (UICP) to improve the strength of the soil layers used to in the construction of roads. This process involved three series of tests conducted on soil specimens of gradually increasing volume. The first series regarded the relative effect of treatment direction, comparing top-down treatment to bottom-upwards and alternating treatment methods on 50-by-100-millimeter soil columns. This was evaluated through unconfined compressive strength (UCS) and the calcium carbonate distribution over the length of the soil, finding that all methods generated a reliable increase in the strength of the soil specimen. This phase of research also included a batch study, evaluating the growth of the ureolytic bacteria Sporosarcina pasteurii in a solution composed of commercially available ingredients, showing that the bacteria could be cultured at a far lower cost (as low as 20 cents per liter) than with lab-grade ingredients ($2.66 per liter). The next series of tests compared the effect of applying treatment solutions to the soil surface directly and using a probe to inject solutions beneath the surface. This was done with 15-centimeter, cylindrical specimens, evaluated through the California bearing ratio (CBR) test. It was determined that the treatment process had the capacity to increase the CBR value substantially (from ~11% up to 188%), and it was suggested that each treatment mechanism resulted in a predictable distribution of calcium carbonate. There was also success in using alternative, commercially-sourced ingredients to facilitate the treatment and improve the CBR value. The last tests centered on the treatment of a 30-centimeter-by-30-centimeter mock road section, combining the treatment mechanisms used at the 15-centimeter-scale to facilitate an increase in the CBR of a soil layer under pavement. Through UICP, the CBR value of this layer was successfully increased.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.