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- Genre: Masters Thesis
Description
Iodide (I-) in surface and groundwaters is a potential precursor for the formation of iodinated disinfection by-products (I-DBPs) during drinking water treatment. The aim of this thesis is to provide a perspective on the sources and occurrence of I- in United States (US) source waters based on ~9200 surface water (SW) and groundwater (GW) sampling locations. The median I- concentrations observed was 16 μg/l and 14 μg/l, respectively in SW and GW. However, these samples were rarely collected at water treatment plant (WTP) intakes, where such iodide occurrence data is needed to understand impacts on DBPs. Most samples were collected in association with geochemical studies. We conclude that I- occurrence appears to be influenced by geological features, including halite rock/river basin formations, saline aquifers and organic rich shale/oil formations. Halide ratios (Cl-/I-, Br-/I- and Cl-/Br-) were analyzed to determine the I- origin in source waters. SW and GW had median Cl-/I- ratios of ~3600 μg/μg and median Br-/I- ratios of ~15 μg/μg. For states with I- concentration >50 μg/l (e.g., Montana and North Dakota), a single source (i.e., organic rich formations) can be identified. However, for states like California and Texas that have wide-ranging I- concentration of below detection limit to >250 μg/l, I- occurrence can be attributed to a mixture of marine and organic signatures. The lack of information of organic iodine, inorganic I- and IO3- in source waters limits our ability to predict I-DBPs formed during drinking water treatment, and new occurrence studies are needed to fill these data gaps. This is first of its kind study to understand the I- occurrence through historical data, however we also identify the shortcomings of existing databases used to carry out this study.
ContributorsSharma, Naushita (Author) / Westerhoff, Paul (Thesis advisor) / Lackner, Klaus (Committee member) / Herckes, Pierre (Committee member) / Arizona State University (Publisher)
Created2018
Description
This thesis examines the use of the moisture swing resin materials employed at the Center for Negative Carbon Emissions (CNCE) in order to provide carbon dioxide from ambient air to photobioreactors containing extremophile cyanobacteria cultured at the Arizona Center for Algae Technology and Innovation (AzCATI). For this purpose, a carbon dioxide feeding device was designed, built, and tested. The results indicate how much resin should be used with a given volume of algae medium: approximately 500 grams of resin can feed 1% CO2 at about three liters per minute to a ten liter medium of the Galdieria sulphuraria 5587.1 strain for one hour (equivalent to about 0.1 grams of carbon dioxide per hour per seven grams of algae). Using the resin device, the algae grew within their normal growth range: 0.096 grams of ash-free dry weight per liter over a six hour period. Future applications in which the resin-to-algae process can be utilized are discussed.
ContributorsBeaubien, Courtney (Author) / Lackner, Klaus (Thesis advisor) / Lammers, Peter (Committee member) / Atkins, Steve (Committee member) / Arizona State University (Publisher)
Created2016
Description
The current level of carbon dioxide in ambient air is increasing and reinforcing the severity of global warming. Several techniques have been developed to capture the gas directly from the air. Moisture swing absorption (MSA) is a mechanism through which a reactive surface, namely resin beads, absorbs carbon dioxide when dry and releases it when wet. The ionic complexity of the surface of the bead interacts with CO2 when H2O contents are low, and CO2 diffuses as bicarbonate or carbonate. Hence, diffusion-drift-reaction equations describe the moving species behavior MS sorbent. A numerical model has been developed previously applying finite difference scheme (FDS) to estimate the evolution of species concentrations over uniform time and space intervals. The methodology was based on a specific membrane and bead geometry. In this study, FDS was employed again with modifications over the boundary conditions. Neumann boundary condition was replaced by Robin boundary condition which enforced diffusion and drift fluxes at the center of the sorbent. Furthermore, the generic equations were approximated by another numerical scheme, Finite volume scheme (FVS), which discretizes the spatial domain into cells that conserves the mass of species within. The model was predicted to reduce the total carbon mass loss within the system. Both schemes were accommodated with a simulated model of isolated chamber that contained arbitrary sorbent. Moreover, to derive the outcomes of absorption/desorption cycles and validate the performance of FVS, Langmuir curve was utilized to obtain CO2 saturation in the sorbent and examine two scenarios: one by varying the partial pressure of CO2 (PCO2) in the chamber at constant H2O (PH2O), or changing PH2O at constant PCO2. The results from FDS approximation, when adjusting the center with Robin boundary condition, show 0.11% lower carbon mass gain than when applying Neumann boundary condition. On the other hand, FVS minimizes the mass loss by 0.3% lower than the original total carbon mass and achieves sorbent saturation without any adjustment. Moreover, the isotherm curve demonstrates that increasing PH2O reduces CO2 saturation and is dependent on the linear and non-linear correlations used to estimate water concentration on the surface.
ContributorsMejbel, Meteb (Author) / Lackner, Klaus (Thesis advisor) / Boyer, Treavor (Committee member) / Wang, Zhihua (Committee member) / Arizona State University (Publisher)
Created2021
Description
Mobile sources emit a number of different gases including nitrogen oxides (NOx) and volatile organic compounds (VOCs) as well as particulate matter (PM10, PM2.5). As a result, mobile sources are major contributors to urban air pollution and can be the dominant source of some local air pollution problems. In general, mobile sources are divided into two categories: on-road mobile sources and non-road mobile sources. In Maricopa County, the Maricopa County Air Quality Department prepares inventories of all local sources [11], [12]. These inventories report that for Maricopa County, on-road mobile sources emit about 23% of total PM2.5 annually, 58% of the total NOx, and 8% of the total VOCs. To understand how future changes how vehicles might impact local air quality, this work focuses on comparing current inventories of PM2.5, black carbon (BC), NOx, and VOCs to what may be expected emissions in future years based on different scenarios of penetration of hybrid gas-electric vehicles (HEV) and electric vehicles (EV) as well as continued reduction in emissions from conventional internal combustion (IC) vehicles. A range of scenarios has been developed as part of this thesis based on literature reports [6], [8], air quality improvement plan documentation [5], projected vehicle sales and registration [3], [4], as well as using EPA’s Motor Vehicle Emission Simulator (MOVES) [9]. Thus, these created scenarios can be used to evaluate what factors will make the most significant difference in improving local air quality through reduced emissions of PM2.5, BC, NOx and VOCs in the future. Specifically, the impact of a greater fraction of cleaner alternative vehicles such as hybrid-electric and electric vehicles will be compared to the impact of continual reductions in emissions from traditional internal combustion vehicles to reducing urban air pollution emissions in Maricopa County.
ContributorsAlboaijan, Fahad A M S (Author) / Fraser, Matthew (Thesis advisor) / Andino, Jean (Committee member) / Lackner, Klaus (Committee member) / Arizona State University (Publisher)
Created2020
Description
In this study, the stereolithography (SLA) 3D printing method is used to manufacture honeycomb-shaped flat sorbents that can capture CO2 from the air. The 3D-printed sorbents were synthesized using polyvinyl alcohol (PVA), propylene glycol, photopolymer resin, and an ion exchange resin (IER). The one-factor-at-a-time (OFAT) design-of-experiment approach was employed to determine the best combination ratio of materials to achieve high moisture swing and a good turnout of printed sorbents. The maximum load limit of the liquid photopolymer resin to enable printability of sorbents was found to be 44%. A series of moisture swing experiments was conducted to investigate the adsorption and desorption performance of the 3D-printed sorbents and compare them with the performance of IER samples prepared by a conventional approach. Results from these experiments conducted indicate that the printed sorbents showed less CO2 adsorptive characteristics compared to the conventional IER sample. It is proposed for future research that a liquid photopolymer resin made up of an IER be synthesized in order to improve the CO2-capturing ability of manufactured sorbents.
ContributorsObeng-Ampomah, Terry (Author) / Phelan, Patrick (Thesis advisor) / Lackner, Klaus (Committee member) / Shuaib, Abdelrahman (Committee member) / Arizona State University (Publisher)
Created2020
Description
The cost of capturing carbon dioxide (CO2) from ambient air needs to be greatly reduced if it is to contribute significantly to mitigating climate change. Ion-exchange resin (IER) with quaternary ammonium cation binds CO2 when dry and releases it when wet without supplemental energy, making the process attractive for economical Direct Air Capture (DAC). In this study, a design case basis was developed for a system of collectors capable of capturing 1000 tons/day of CO2 via moisture swing sorption. The model uses varying weather parameters such as temperature, wind speed, and relative humidity to understand the impact of weather on the sorbent loading, cycle time (capture and regeneration), and net water loss. Two independent isotherm models, namely Flory Huggins and the modified Langmuir isotherm model were used to estimate the water and CO2 loading of the resin respectively as a function of relative humidity. The capture model suggests a higher capture rate during the summer and daytime (in a diurnal cycle) as the relative humidity is lower. A design optimization model was developed to minimize the capture time and maximize the sorbent loading. The crude rate production and the net water loss can help conduct an economic analysis to determine the cost of carbon capture.
ContributorsTalha, Mohammad Abu (Author) / Green, Matthew (Thesis advisor) / Lackner, Klaus (Committee member) / Cirucci, John (Committee member) / Arizona State University (Publisher)
Created2023