MS, University of Cincinnati, 2021, Engineering and Applied Science: Chemical Engineering

Pore diffusion from a bulk sour gas phase to a bulk potassium carbonate liquid phase was modelled based solely on pore diffusion resistances. This modelling was done for ideal solutions at varying kinetic rates for the carbon dioxide-water reaction as well as various system parameters. The modelling was done utilizing Python and several pre-built libraries such as Scipy and Jax. The model was constructed starting from the original continuity equations combined with Fick's Law, and numerically solving the resultant system of differential equations. Primarily, two different methods were required to assess systems with and without kinetic reaction-based diffusion resistances. Assuming infinitely fast reaction in all cases allowed the system to be integrated directly, while the system with kinetic resistances required a collocation algorithm to solve.

Committee: Stephen Thiel Ph.D. (Committee Chair); Carlos Co Ph.D. (Committee Member); Greg Harris Ph.D. (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy, The Ohio State University, 2020, Chemical Engineering

Carbon dioxide (CO2) is an important greenhouse gas that contributes to global warming. To combat the rising emissions of CO2 into the atmosphere, scientists and researchers have devised several methods of carbon capture and storage (CCS), including the use of membranes to trap CO2 molecules, valves to condense CO2 from a mixture of gases, etc. Supersonic separation is a novel method of gas-gas separation that has been used to separate natural gas from other gases. It has been suggested for and is being currently studied as a method for the removal of CO2 from flue gas before it enters the atmosphere. Supersonic separation relies on the condensation of CO2 clusters into particles large enough to be inertially separated, requiring a size of approximately 1 micrometer in diameter. In order to effectively design hardware to capture CO2 using this mechanism, we need to study and collect fundamental nucleation properties of CO2 and quantify the process under supersonic flow conditions. To this end, we studied the condensation of CO2 in two supersonic nozzles of differing expansion rates, T1 and T3, and sought to quantify the onset of nucleation, particle size distributions, and aerosol number densities. First, we confirmed that homogeneous nucleation of CO2 could not take place in nozzle T1 when expansions started from a stagnation temperature of 20°C, no heat release was observed in pressure trace measurements at 7.0 to 11 mol% CO2. Lowering the stagnation temperature to 10°C showed some evidence of heat release, but it was uncertain to what extent that was due to condensation of particles or whether the nozzle overexpansion had caused a shock to increase the temperature and pressure of the flow. Analysis of the saturation curve suggests the nucleation event was incomplete, and lower temperatures were required for a full characterization. Second, we performed a series of pressure trace measurements (PTM) in nozzle T3 for concentrations of CO2 in Ar ranging from 0.5 (open full item for complete abstract)

Committee: Barbara Wyslouzil (Advisor); Nicholas Brunelli (Committee Member); Isamu Kusaka (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy, University of Toledo, 2016, Chemical Engineering

Concerns over the effects of anthropogenic carbon dioxide (CO2) emissions from fossil-fuel electric power plants has led to significant efforts in the development of processes for CO2 capture from flue gas. Options under consideration include absorption, adsorption, membrane, and hybrid processes. The US Department of Energy (DOE) has set goals of 90% CO2 capture at 95% purity followed by compression to 140 bar for transport and storage. Ideally, the Levelized Cost of Electricity (LCOE) would increase by no more than 35%. Because of the relatively low CO2 concentration in post-combustion flue gas, most of the reported process configurations for membrane systems have sought to generate affordable CO2 partial pressure driving forces for permeation. Membrane Technology and Research, Inc. (MTR) proposed the use of an air feed sweep system to increase the CO2 concentration in flue gas. This process utilizes a two-stage membrane process in which the feed air to the furnace sweeps the flue gas in the second stage to reduce the flow of CO2 in the effluent to 10% of that leaving the furnace. Such a design significantly reduces capture costs but leads to a detrimental reduction in the oxygen concentration of the feed air to the boiler. In this dissertation, the economic viability of combined cryogenic-membrane separation is evaluated. The work incorporates the tradeoff between CO2/N2 selectivity and CO2 permeability that exists when considering the broad range of potential membrane materials. Of particular interest is the use of lower selectivity, higher permeability materials such as polydimethylsiloxane (PDMS). Additional enriching stages are required in a membrane-cryogenic air feed sweep configuration to enable use of these materials and achieve the 90% CO2 recovery and 95% purity targets. The higher CO2 permeance of PDMS significantly reduces the total module membrane area requirement and associated capital cost (CAPEX). However, the lower selectivity increases th (open full item for complete abstract)

Committee: GLENN LIPSCOMB PhD (Committee Chair); MARIA COLEMAN PhD (Committee Member); YAKOV LAPITSKY PhD (Committee Member); CONSTANCE SCHALL PhD (Committee Member); MATTHEW FRANCHETTI PhD (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy (PhD), Ohio University, 2013, Chemistry (Arts and Sciences)

A series of new environmentally and catalytically significant bioinorganic redox active pseudotetrahedral Ni(II) thiolate and Ni(II) phenolate (S=1, d8) complexes were synthesized and fully characterized as small molecular models in order to study the coordination mode of the Ni-S bond that is biologically significant in anaerobic and archaebacterial enzymes. During this characterization a unique Ni-S ligation mode was discovered and modulated by steric titration and details were further investigated. Nickel thiolate bond reactivity towards electrophilic alkylation with methyl iodide (MeI) is briefly discussed. A series of new Ni(II) phenolate complexes were synthesized and characterized as well as their O2 activation activity were investigated as a model for nickel substituted Copper Amine Oxidase (CAO). During this O2 reduction investigation, depending on the ligand bulk on the parent TpPh,Me/TpMe,Me ligand (where, TpPh,Me= hydrotris{3-phenyl-5-methyl pyrazol-1-yl}borate; TpMe,Me= hydrotris{3,5-dimethyl pyrazol-1-yl}borate) either a C-H or a C=C bond activation was observed. In addition, surprisingly where C-H activation was not possible, a CO2 capture activity was observed by a reactive intermediate nickel species.

Committee: Micahel Jensen PhD (Committee Chair); Jeffrey Rack PhD (Committee Co-Chair); Hugh Richardson PhD (Committee Member); Alexander Govorov PhD (Committee Member) Subjects: Biochemistry; Chemistry; Inorganic Chemistry; Organic Chemistry

Doctor of Philosophy, The Ohio State University, 2013, Chemical and Biomolecular Engineering

Hydrogen is produced in large scale by steam reforming followed by water-gas-shift reaction, which yields a product stream consisting mainly of H2 and CO2. Purification of H2 from other gaseous compounds, mainly CO2, with significantly improved energy and cost efficiencies therefore becomes a crucial step for hydrogen economy that could ultimately provide hydrogen as a clean, renewable fuel as well as versatile chemical with wide commercial uses, reduce the reliance of modern industries on petroleum, and restrain global greenhouse gas emissions. Facilitated transport membranes are well suited for CO2/H2 separation due to high selectivity accompanied with high CO2 permeability, H2 product recovery at high pressure, and low energy and cost consumptions. The objective of this research is to develop advanced CO2-selective facilitated transport membranes with desired properties for practical gas separation applications. Novel facilitated transport membranes have been synthesized by incorporating sterically hindered amines as CO2 carriers in crosslinked polyvinylalcohol networks. The membrane has shown high, stable performance in terms of CO2 permeability (about 3719 Barrers) and CO2 selectivities vs. H2 (about 319) and N2 (about 677) for a period of at least 430 hours at 110 Degree Celsius and typical fuel cell operating pressure of 2 atm. Facilitated transport membranes with ultrathin separation layers (less than 2 micrometers) were also synthesized and exhibited promising selectivity and permeance for CO2 capture from flue gas. An average CO2 permeance of 726 GPU with CO2/N2 selectivity of 162 at 1 atm and 102 Degree Celsius has been achieved. This research further exploited the superlative mechanical property of multi-walled carbon nanotubes (MWNTs) to reinforce the mechanical strength of amine facilitated transport membranes and successfully developed durable nanostructured polymer-MWNT membranes by incorporating MWNTs into the crosslinked poly (open full item for complete abstract)

Committee: W.S. Winston Ho (Advisor); L. James Lee (Committee Member); Shang-Tian Yang (Committee Member); Rachel G. Kleit (Committee Member) Subjects: Chemical Engineering

Master of Science in Environmental Science, Youngstown State University, 2010, Department of Geological and Environmental Sciences

In response to increasing pressure to reduce carbon emissions, algae photobioreactors have become central to finding environmentally-sustainable mitigation strategies for carbon capture. Although a good number of photobioreactors have been proposed, only a few of them can be practically used for large-scale algal CO2 sequestration and for that matter mass production of algae. One of the major factors that limit their practical application with algal mass cultures is mass transfer. Against this background, the purpose of this research was to test a scalable bench scale photobioreactor with a capacity to enhance the mass transfer of CO2 (gas) into a fresh water Chlorella vulgaris algal culture (liquid) phase. To achieve this, a packed vertical column being referred to as a Packed Bubble Column Photobioreactor (PBCP) was used to increase gas-liquid contacting surface area enhancing the mass transfer of the gas into the liquid phase. The dynamics of the PBCP showed more moles of CO2 were transferred with higher composition of inlet CO2 at same algal culture composition. Higher algal culture concentration showed lower composition of CO2 in the outlet gas from of the reactor. CO2 increased in outlet gas composition with increasing rate of moles of CO2 into the reactor. During 45 minutes of steady state semi-continuous experimental test runs with 350 mL of algal culture at 0.21 and 0.35 g/L and CO2 (of 5.0 – 9.5% composition at flow rate of 25.0 mL/min to 112 mL/min); CO2 transferred into the algal culture phase was typically in the range of 10 to 30%. These results have shown that the PBCP is able to significantly enhance the transfer of CO2, and reductions of carbon dioxide greater than 30% are achievable with higher algal cultures and CO2 composition in the reactor.

Committee: Douglas Price PhD (Advisor); Felicia Armstrong PhD (Committee Member); Gary Walker PhD (Committee Member); Lauren Schroeder PhD (Committee Member) Subjects: Atmosphere; Biochemistry; Biology; Chemical Engineering; Environmental Science; Gases

Master of Science in Environmental Science, Youngstown State University, 2008, Department of Geological and Environmental Sciences

Adsorption is considered one of the more promising technologies for capturing CO2 from flue gases. This research shows an efficient chemical adsorption method capable of capturing carbon dioxide under moist conditions from flue gases of coal-fired power plants. Carbon dioxide was chemically adsorbed by the reaction K2CO3*1.5H2O + CO2 ↔ 2KHCO3 + 0.5H2O + heat. Moisture however, plays a significant role in the chemical adsorption process, which readily facilitates the adsorption process. Moisture usually contained as high as 8-17% in flue gases, badly affects the capacity of conventional adsorbents such as zeolites, but the present technology has no concern with moisture; water is rather necessary in principle as shown in the equation above. Carbon dioxide uptake occurred at a temperature of 60°C and the entrapped carbon dioxide was released by the decomposition of potassium bicarbonate to shift the reaction in the reverse direction. The decomposition occurred at high enough temperatures of 150°C to ensure complete regeneration of the sorbent. For the purpose of this research, emphasis was placed more on the adsorption process. When compared to other processes such as the conventional amine process, it provided an efficient, low utility cost and energy-conservative effect. The activated carbon was prepared by 20% by weight of K2CO3 and samples used during the experimental runs were dried at 60°C for the 26-hour runs and at 25°C and 125°C for the air-dried and oven-dried samples respectively for the 48-hour runs. The samples all got to the saturation point after 6 hours of exposure to carbon dioxide and gave adsorption capacities in the range of 2.5 to 3.5mol CO2/mol K2CO3 for all experimental runs performed in this research.

Committee: Douglas Price PhD (Committee Chair); Felicia Armstrong PhD (Committee Member); Jeffrey Dick PhD (Committee Member); Alan Jacobs PhD (Committee Member) Subjects: Chemical Engineering; Chemistry; Energy; Engineering; Environmental Engineering; Environmental Science

PhD, University of Cincinnati, 2009, Engineering : Chemical Engineering

Global warming is unequivocal due to greenhouse effect, majorly caused by increasing concentration of carbon dioxide in the atmosphere. Using metal oxide sorbents, such as calcium oxide, is one of the most potent ways to separate CO2 in contrast to existing or emerging technologies today. Unlike other technologies, calcium-based separation can be applied easily above 550 °C for capturing CO2.Calcium-based sorbents were prepared first using inorganic and organometallic precursors (OMP) by calcination or wet chemistry. Sorbent performance was tested using a thermogravimetric analyzer (TGA). Amongst all, the sorbents prepared from calcium propionate and calcium acetate exhibited the highest capacity to uptake CO2, converting from calcium oxide to calcium carbonate. These two sorbents possessed higher BET surface area and larger pore volume than the other sorbents. Thermal decomposition of these two OMPs resulted in the maximum evolution of heat, which could eventually lead to the generation of larger macropores, thus explaining the resultant CO2 uptake capacity demonstrated. The sorbents originated from OMPs and involved more heat during formation of calcium carbonate exhibited better performance. Therefore, flame technique, which involves with combustion of OMPs, was applied to synthesis sorbents. Scalable flame spray pyrolysis (FSP) is unique in making controllable sized nanoparticles. Such flame-made sorbents consisted of nanostructured calcium oxide and calcium carbonate with high specific surface area (40-90 m2/g), exhibiting faster and higher CO2 uptake capacity than non FSP-made sorbents. In multiple carbonation/decarbonation cycles, the nanostructured sorbents demonstrated relatively stable, reversible and high CO2 uptake capacity sustaining molar conversion at about 50% after 60 such cycles,. The high performance of flame-made sorbents is best attributed to their nanostructure (30-50 nm grain size) that allows operation in the reaction-controlled carbonation (open full item for complete abstract)

Committee: Panagiotis Smirniotis PhD (Committee Chair); Yuen-Koh Kao PhD (Committee Member); Jerry Lin PhD (Committee Member); Neville Pinto PhD (Committee Member); Sotiris Pratsinis PhD (Committee Member) Subjects: Chemical Engineering; Energy; Environmental Engineering

Master of Science, The Ohio State University, 2011, Geological Sciences

Subtle shifts in the lithology or diagenetic history of a sedimentary formation may result in different reservoir properties of that formation, by affecting porosity and permeability in varied ways. This may create a geographic heterogeneity that will alter the accuracy of reservoir storage estimations of a formation. The Mt. Simon and Rose Run Sandstones of Ohio are both established as appropriate targets for the sequestration of supercritical CO2, but each of these formations may contain heterogeneities that are heretofore unaccounted for by standard well exploration. The porosity and permeability of these formations may differ based upon their local diagenetic histories. To account for these differences, the concentrations of quartz and feldspar within these sandstones offer evidence of diagenetic processes that have occurred in the past and those that may still occur in the future. Grain-size variations and any geographic trends they show can also be used as evidence of diagenetic variations that may indicate further heterogeneities that will affect the porosity and permeability of the formation on a local level. In this study, feldspar concentrations in both the Rose Run and Mt. Simon Sandstones are studied, on a microscopic level, and are shown to be extremely low with subtle variation of concentration based on location. Grain sizes of these formations also show subtle variations based on geographic location. Both results show that further study into the locally geographic differences of these formations will be necessary in order to accurately evaluate their storage capacity.

Committee: Michael Barton Dr. (Advisor); Loren Babcock Dr. (Committee Member); David Cole Dr. (Committee Member) Subjects: Earth; Energy; Environmental Engineering; Environmental Geology; Environmental Science; Environmental Studies; Geological; Geology; Geotechnology

BA, Oberlin College, 2011, Physics and Astronomy

There are a range of environmental and industrial applications to capturing carbon dioxide from gas mixtures. Currently, materials being used in these applications bind carbon dioxide too strongly for practical purposes, such that they require large amounts of energy to be regenerated for reuse. Highly porous materials called metal-organic frameworks (MOFs) could serve much more effectively as carbon-capturing materials, as they suck up large amounts of carbon dioxide gas at pressures and temperatures that are nearly ideal for carbon-capture applications. Moreover, they require much less energy than current materials to release the carbon dioxide and be regenerated. Additionally, many different structures can be created fairly easily, so scientists are on the hunt for the ideal carbon-capturing MOF. In this thesis we study Mg-MOF-74, a particularly promising metal-organic framework material for separating carbon dioxide from gas mixtures. We use infrared spectroscopy to probe the interactions between the Mg-MOF-74 host and both carbon dioxide and methane. By shining infrared radiation on Mg-MOF-74 with gases trapped in it and looking at which frequencies of radiation are absorbed by the bound gases, we can learn about the binding nature of the framework. This in turn helps us to better understand the properties are are preferable in metal organic frameworks, and will aid chemists in fabricating new structures that are ideal for carbon-capture and other applications.

Committee: Stephen FitzGerald PhD (Advisor) Subjects: Molecular Physics; Physical Chemistry; Physics

Doctor of Philosophy, University of Akron, 0, Chemical Engineering

Carbon capture and plastic waste upcycling are both effective strategies for combatting climate change by reducing CO2 emissions in the atmosphere. Carbon capture technology is characterized by three major methods: (i) post combustion capture (ii) pre-combustion and (iii) oxy-combustion. CO2 absorption, which is a type of post-combustion technology, is reported to be the dominant capture technology. The overall performance of this process is majorly determined by parameters such as CO2 capture capacity, amine efficiency and binding energy. A key issue of the CO2 absorption process is the development of a sorbent that will effectively absorb CO2 in a stream of flue gas and then release it in such a way that the sorbent is not thermally degraded, clean, and ready for re-use. The release of the captured CO2 typically involves the use of elevated temperatures for regeneration of the sorbent which leads to high energy penalty, solvent loss, corrosion, and high operation costs. This research focuses on the application of an in-situ infrared spectroscopic (IR) approach to study the structure of adsorbed CO2 species and reaction mechanism during CO2-amine reactions under pure CO2 and direct air capture cycles as a method of developing cost-effective and energy efficient sorbents. The band assignments of these species are identified by HCl probing. In addition, we explore alternative routes for regeneration that involve the coupling of renewable energy in the form of electricity to generate non thermal plasma with in-situ infrared (IR) spectroscopy to separate adsorbed CO2 from novel developed polyamine sorbents. We explored the reaction mechanism of non-thermal plasma induced reaction for the release of adsorbed CO2 from solid amine sorbents packed in a glass cylindrical tube reactor. The lead vs lag relationship of released CO2 and other products are investigated and characterized. Furthermore, we apply the concept of plasma-enabled gas-phase electrocatalysis for an effi (open full item for complete abstract)

Committee: Steven Chuang (Advisor); Mesfin Tsige (Committee Member); Lu-Kwang Ju (Committee Member); Linxiao Chen (Committee Member); Qixin Zhou (Committee Member) Subjects: Chemical Engineering; Climate Change; Energy; Sustainability

Doctor of Philosophy, Miami University, 2024, Geology and Environmental Earth Science

Geologic formations suitable for energy storage such as CO2 or hydrogen storage, are typically selected based on a defined set of screening criteria, such as depth and salinity. During screening and site selection, multiple formations are evaluated and compared to select an optimal site to meet storage and injection goals. However, during this process, formations are typically compared based on average reservoir properties, such as average porosity and net thickness, which does not account for the complexity of the reservoir. Additionally, existing screening and site selection systems are not designed for CO2 storage and not easily repeatable for comparable results. Because of this, a new system was developed which considers regional scale geologic complexity and reservoir scale variability to produce a complexity score, and data quality and proximity to produce a confidence score. This study began with an exploration of which geologic variables, both quantitative and qualitative, best represent geologic complexity and heterogeneity, how variables could be combined to rank a site or system, and how this correlated with performance of existing sites. Next, a ranking system was developed based on the identified variables and applied to saline storage formations in Ohio to test the applicability and limitations of the system. Finally, the ranking system was applied to specific sites in the Mt. Simon sandstone from the Illinois, Michigan, and Appalachian basins and compared to the success of injection. Overall, this study aims to present an extended site selection strategy that utilizes data and information typically gathered during the feasibility assessment stage which takes into consideration the complexity of a storage system, which could have long-term negative effects on the successful development of a storage project.

Committee: Brian Currie (Advisor); Mike Brudzinski (Committee Member); Claire McLeod (Committee Member); Jonathon Levy (Committee Member) Subjects: Geology

Doctor of Philosophy, The Ohio State University, 2023, Chemical Engineering

The primary objective of the dissertation outlined here is to find superior alternatives to amines as CO2-reactive carriers in facilitated transport membranes (FTMs). While conventional amine-based FTMs have proven highly efficient in separating CO2 from N2 with minimal energy requirements, their limited CO2 loading capacity remains a significant drawback. When these conventional amines interact with CO2, they form carbamate products, resulting in a loading capacity of 0.5 mol CO2 per mole of carrier. On the other hand, tertiary amines lack the necessary proton for nucleophilic addition to CO2, leading them to react with carbonic acid to form bicarbonate products, thus enabling a loading capacity of 1 mol CO2 per mole of the carrier. However, the slow formation of carbonic acid limits the overall reaction rate, leading to an inferior separation efficiency than conventional amines. In contrast, strong bases like amidines can also form bicarbonate products by reacting with CO2, owing to the presence of a stable two-N resonance structure (–N=CH–NH–). These compounds exhibit superior nucleophilicity compared to tertiary amines and readily undergo protonation by water to release OH−, thereby accelerating the formation of bicarbonate products through the interaction of CO2 and OH−, rather than relying on the formation of carbonic acid. Consequently, amidines are currently under scrutiny as potential candidates for this role. The incorporation of CO2 carriers in FTMs can be achieved by dispersing small molecules as mobile carriers or by utilizing polymers as fixed-site carriers. However, due to their low boiling points, small molecules are susceptible to carrier loss, making polymers the more suitable choice. In our project, I synthesized a polymer with a high density of amidine groups, poly(ethylene formamidine) (PEF), using the shortest diamine, ethylenediamine (EDA), as monomers. By optimizing the polymerization conditions, the highest weight-average molecula (open full item for complete abstract)

Committee: W.S. Winston Ho (Advisor); David Wood (Committee Member); Andre Palmer (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy, The Ohio State University, 2023, Civil Engineering

Reducing CO2 emissions will be critical for meeting global targets of net zero CO2 emissions by the year 2050 and net negative CO2 emissions by 2100. To help meet these emission reduction targets there will need to be a rapid transition from a historical reliance on fossil fuels for energy generation to renewable and low CO2 emission energy generation technologies, a so-called energy transition. The energy transition will feature an increase in demand for valuable resources like rare earth elements and see widespread deployment of carbon capture, utilization, and storage infrastructure. In the first chapter we explore a novel trap-extract-precipitate (TEP) system that looks to trap rare earth elements (REEs) found in coal mine drainage before later extracting the REEs from the trap material. We apply a techno-economic analysis and life cycle assessment to two different iterations of the TEP system design to determine a levelized cost of the process and associated environmental and human health impacts. Our results indicate that the levelized cost of the process is $278/gT-REE and $86/gT-REE for two designs using different industrial by-products. Further, when considering just the passive treatment cell of the system design, we observe environmental and human health benefits that are lost once we shift the scope to include the chemical extraction of REEs. Chapter 3 evaluates the impact of stacked storage on carbon capture and storage (CCS) systems by looking at how networks change when CO2 is emplaced in different geologic CO2 storage (GCS) locations. This case study focuses on Oklahoma, which has GCS resources and existing CO2-EOR operations, both needed for stacked storage. We use an economic engineering geospatial linear optimization model, SimCCSPRO, to determine the least cost combination of point sources, GCS locations, and pipeline networks. Our results suggest point sources of CO2 drive CCS pipeline network deployment. Additionally, we identify counties t (open full item for complete abstract)

Committee: Jeffrey Bielicki (Advisor); Daniel Gingerich (Committee Member); Gil Bohrer (Committee Member); Jordan Clark (Committee Member) Subjects: Civil Engineering; Environmental Engineering

Master of Science in Environmental Science, Youngstown State University, 2022, Department of Physics, Astronomy, Geology and Environmental Sciences

Anthropogenic increases in greenhouse gases, especially carbon dioxide, have been associated with rising global temperatures. These changes have led to desertification, heat waves, ecosystem disruption, intensification of severe weather, and loss of agricultural productivity. To mitigate against these adverse effects, carbon sequestration approaches such as afforestation and reforestation are being explored in landscapes, including urban ecosystems. The amount of forest cover and carbon storage was evaluated for the Youngstown Metropolitan Area (YMA), located in northeast Ohio. Four urbanized sub-watersheds of the Mahoning River within the YMA were chosen. The amount of forest cover for each sub-watershed for the years 2001 and 2019 was determined using ArcGIS Pro and a 50- year land cover projection was generated using the TerrSet software. Results indicate that YMA lost approximately 40ha (5,330ha to 5,290ha) of forest cover between 2001 and 2019, while developed areas gained 200ha (from 18,400ha to 18,600ha) between the same period. While the Dry Run Creek is the only sub-watershed in the study area with an increased forest area (from 1,420ha in 2001 to 1,460ha in 2019), the Crab Creek sub watershed registered the highest decrease (from 1,760ha to 1,720ha) during the same period. Currently, the area under forest cover in the Crab Creek sub-watershed is the largest (1,720ha or 17.2km2 ), storing approximately 60,700t of carbon. On the other hand, the Andersons Run-Mill Creek sub-watershed has the lowest forest area 524ha (5.24km2 ), sequestering up to 18,500t of carbon. By 2069, the area under forest cover in Crab Creek is predicted to decrease by 70ha (from 1,720ha in 2019 to 1,650ha in 2069), while iv developed land area would increase by 90ha (from 3,350ha in 2019 to 3,440ha in 2069). Although 90.3% of Andersons Run-Mill Creek sub-watershed is expected to be developed by 2069, forest cover is predicted to occupy 6.9% of its landscape. This study showed (open full item for complete abstract)

Committee: Peter Kimosop PhD (Advisor); Felicia Armstrong PhD (Committee Member); Colleen McLean PhD (Committee Member); Lauren Schroeder PhD (Committee Member) Subjects: Environmental Studies; Forestry; Gases; Geographic Information Science

Doctor of Philosophy, The Ohio State University, 2022, Chemical Engineering

Developments of green energy alternatives (e.g., ethanol) and advanced CO2 capture technologies play a crucial role in solving the energy and climate crisis. Specifically, membrane-based separation processes provide opportunities as potentially energy-efficient means to extract alcohols or capture CO2. For alcohol extraction, ultrathin-film nanoporous membranes such as zeolite nanosheets may offer large separation factors and high fluxes because of their selective ethanol-to-water adsorption and short diffusion pathway. However, systematic investigations of potential nanosheet candidates are still missing to date, while atomistic understandings of their separation mechanism and structure-property relationship remain limited. For CO2 capture, facilitated transport membranes (FTMs) that utilize reversible chemical reactions between amino groups and CO2 have been demonstrated to offer notably enhanced selectivity and permeance. However, molecular understandings of the reactive diffusion mechanism of CO2 in the FTMs remain limited. This dissertation conducts computational studies to study membrane materials for ethanol separation and CO2 capture. Specifically, in Chapter 2, a screening study of zeolite nanosheets as pervaporation membranes for ethanol separation is discussed to show their separation performance and shed light on the relationship between separation factors, adsorption selectivities, and structural features. In Chapter 3, understandings achieved in the previous chapter are applied to study the alcohol/water pervaporation separation using zeolite membranes with various Si/Al ratios. Key factors identified in Chapter 2, such as surface silanol density and adsorption selectivity, are again shown to play an important role, which rationalizes the separation performance observed experimentally. Aside from zeolite materials, metal-organic frameworks (MOFs) have emerged as a promising class of nanoporous materials as membrane candidates. In order to facilitate (open full item for complete abstract)

Committee: W.S. Winston Ho (Advisor); Nicholas Brunelli (Committee Member); Li-Chiang Lin (Advisor) Subjects: Chemical Engineering

Doctor of Philosophy, The Ohio State University, 2021, Chemical Engineering

Polymeric facilitated transport membranes (FTMs) incorporate reactive carriers (e.g., amino groups) in the polymeric matrix and uniquely utilize the carrier–CO2 reaction to enhance the CO2 permeation. Consequently, FTMs offer both high CO2 permeance and large CO2/N2 selectivity. In this study, a computational methodology was developed to elucidate how carriers influence the intricate interplay of underlying physical and chemical processes that determine the separation performance of FTMs. Commonly adopted amine carriers, including the poly(N-vinylformamide-co-vinylamine) (PNVF-co-VAm) fixed-site carrier and piperazine glycinate (PZ-Gly) and 2-(1-piperazinyl)ethylamine sarcosinate (PZEA-Sar) mobile carriers, were first studied. By using density functional theory (DFT) calculations, molecular dynamics (MD) simulations, and Monte Carlo methods, the carriers were evaluated from the perspectives of reaction chemistry, guest molecule (i.e., mobile carrier, CO2, and N2) diffusion, and N2 sorption. The computational observations were found in good agreement with experimental results, validating the reliability of the computational methodology. In order to improve the CO2 loading capacity, sterically hindered amine carriers were designed and shown to offer improved reaction chemistry. A new parameter of steric hindrance, N exposure, was proposed and validated to facilitate future design of carriers. Another class of reactive carriers with strong basicity have also been evaluated and demonstrated desirable reaction chemistry. These carriers are therefore expected to offer higher CO2 loading capacities than the amine carriers. The diffusion and N2 sorption in promising mobile carriers were then investigated using MD and Monte Carlo simulations, respectively. Sterically hindered amine mobile carriers typically demonstrated lower mobile carrier and CO2 diffusivities. Other candidates were found to offer fast guest molecule diffusion but suffered from larger N2 permeabilities. (open full item for complete abstract)

Committee: W.S. Winston Ho (Advisor); Li-Chiang Lin (Advisor); Aravind Asthagiri (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy, The Ohio State University, 2020, Chemical Engineering

Membrane technology is one of the most important options or gas separation applications. In this research, two kinds of CO₂-selective facilitated transport membranes were investigated for different separation tasks. The first group of membranes comprised fluoride- and hydroxide-containing species for CO₂ removal and H₂ purification for solid oxide fuel cells (SOFCs). The other type of membranes incorporated primary amino groups as the carriers for carbon capture from flue gas. The anode exhaust of SOFCs contains a considerable amount of unused fuel (e.g., H₂). CO₂-selective membranes were utilized to remove CO₂ from the anode exhaust and the purified H₂ could be recycled for the SOFC. The oxidatively stable membranes developed previously were stable at 120ºC but showed performance degradation at 130ºC. Hence, more thermally stable fluoride- and hydroxide-containing species were screened for a better membrane composition. The optimized membrane containing tetramethylammonium fluoride showed a CO₂ permeance of 108 GPU and a CO₂/H₂ selectivity of 106 at 120ºC, and the membrane stability was improved by four times at 130ºC. Next, a process modeling was done to assess the separation performance and economics of two membrane processes after they were integrated into SOFCs, respectively. One membrane process had a vacuum on the permeate side (SOFC-MBvac) and the other used an air sweep (SOFC-MBair). It was found that a complete recycle of the anode exhaust through the membrane stage could enable a zero-carbon electricity generation by the SOFC and a system fuel utilization above 99%. Furthermore, the SOFC-MBvac process was shown to have a lower CO₂ removal cost than the SOFC-MBair ($83.9 vs. $99.9/tonne). The research demonstrated the enormous potential of CO₂-selective facilitated membranes in purifying the anode exhaust recycle of SOFCs and making the process more fuel-efficient. The second part of the dissertation concerns the study on mem (open full item for complete abstract)

Committee: W.S. Winston Ho (Advisor); Stuart Cooper (Committee Member); Andre Palmer (Committee Member) Subjects: Chemical Engineering; Polymers

Doctor of Philosophy, The Ohio State University, 2020, Chemical Engineering

Despite the rapid development of renewable energy technologies, fossil fuels still account for the majority of the energy consumed by human activities. The modern society is faced with two concerns raised by the massive consumption of fossil fuels, including the potential shortage and exhaustion of fossil fuels in the future due to their non-renewable nature, and the emissions of CO2 and other pollutants associated with fossil fuel combustion and conversion processes. To address these challenges, it is essential to simultaneously improve the energy efficiency and to incorporate CO2 capture and pollution abatement strategies into these energy conversion processes. However, conventional CO2 capture technologies are usually energy-intensive, which further lowers the energy efficiency of the overall systems and aggravates the upcoming energy shortage concern. To address these issues, it is urgent for novel technologies that can perform CO2 capture while maintaining high energy efficiency to be developed and implemented. Besides, efficient utilization of renewable fuels such as biogas as substitutes for fossil fuels also requires considerable research efforts. Chemical looping provides a novel and versatile technology platform for fossil and renewable energy conversions. Chemical looping achieves in situ CO2 separation and capture without adding extra CO2 capture units. As a result, the energy efficiency of chemical looping processes with near complete CO2 capture is comparable to conventional systems without CO2 capture. Chemical looping technology is not only applicable to electricity production, but also to chemical synthesis and H2 production, with more intensified process schematics and higher energy efficiency than conventional systems. This dissertation encompasses the studies on the utilization of chemical looping technology for chemicals and H2 production and electricity generation from a process system perspective. Process simulation is conducted on five (open full item for complete abstract)

Committee: Liang-Shih Fan (Advisor); Isamu Kusaka (Committee Member); Li-Chiang Lin (Committee Member); Derek Hansford (Committee Member) Subjects: Chemical Engineering

Master of Science, The Ohio State University, 2019, Chemical Engineering

Carbon capture has been regarded as one of the viable solutions to mitigate the global warming effect due to CO2 emission and sustain the use of fossil fuels, but the energy load associated with implementing carbon capture in coal-fired power stations can notably decrease the efficiency of power generation. To overcome the deficiency, exploring novel materials for carbon capture has drawn significant attention. Specifically, metal-organic frameworks (MOFs) have been identified as promising adsorbents for carbon capture because of their highly tunable nature, selective adsorption, and large adsorption capacity. A large number of MOFs have been discovered in recent years, and many of them have been demonstrated to possess promising separation performance. To date, most of the studies reported have mainly focused on exploring potential MOF candidates by evaluating their adsorption properties (e.g., selectivity) or their performance using a process model. Although MOFs have been demonstrated to show potentially better performance (i.e., less energy intensity) than MEA, the overall impact by this emerging new class of materials remains unknown. To this end, to facilitate the development of a new technology based on MOF adsorbents, the overall impacts of implementing MOF-based carbon capture, including the energy load and resource depletion from the MOF synthesis process as well as other steps in the whole life cycle of MOFs, should be considered. In this study, we present a comprehensive life-cycle analysis for a selected set of 50 MOFs to evaluate the overall impact of MOF-based post-combustion carbon capture and compared with that by MEA. Our results again show the great promise of MOFs in carbon capture. From the life cycle point of view, besides the energy load of capturing carbon using MOFs, we find significant impacts from the use of solvent in MOF-based carbon capture. Furthermore, the key role of MOF stability is also identified in determining the overall impact. (open full item for complete abstract)

Committee: Li-Chiang Lin (Advisor); Bhavik Bakshi R (Advisor) Subjects: Chemical Engineering