Date of Award
2024-08-01
Degree Name
Master of Science
Department
Physics
Advisor(s)
José Leobardo Bañuelos
Abstract
The Earth’s temperature has increased in the last six decades mainly due to the emissions of greenhouse gases, including carbon dioxide (CO2). Mineral looping using magnesium oxide (MgO) is a promising approach for direct air capture (DAC) of CO2 from the atmosphere at the GtCO2/yr scale. The presence of humidity during the carbonation process will lead to a reaction between the MgO and water resulting in magnesium hydroxide formation, Mg(OH)2, growing over the MgO surface forming a shell-like structure. The influence of temperature and relative humidity variation on heterogeneous nucleation and crystal growth kinetics of Mg(OH)2 on MgO is not well understood under environmentally/DAC-relevant conditions. In this thesis, quartz crystal microbalance (QCM) commercial crystals were coated with a ~90nm-thick MgO film using pulsed laser deposition (PLD). Experiments to investigate brucite formation using multiharmonic QCM with Dissipation analysis (QCM-D) were conducted by flowing deionized water at 20 µl/min over the MgO film, as well as under water vapor exposure. Results of QCM-D analysis using first-order kinetic models will be presented. Batch experiments were also conducted using three distinct types of MgO powder. Similar quantities of each powder were exposed to varying levels of relative humidity (RH) over different durations. The mass changes in these samples were meticulously measured. Subsequently, the results were analyzed using first-order kinetic models. These samples were analyzed using small angle x-ray scattering (SAXS) and wide-angle x-ray scattering (WAXS) to relate molecular and nanoscale structural changes to the QCM studies. This work allowed estimates of growth rates by analyzing the time-dependence of mass loss under each experimental condition.
Language
en
Provenance
Received from ProQuest
Copyright Date
2024-08-01
File Size
78 p.
File Format
application/pdf
Rights Holder
Pedro Josue Hernandez Penagos
Recommended Citation
Hernandez Penagos, Pedro Josue, "Determining Heterogeneous Growth Rates Of Brucite On Magnesia Using Multiharmonic Qcm-D And X-Ray Scattering Methods" (2024). Open Access Theses & Dissertations. 4180.
https://scholarworks.utep.edu/open_etd/4180