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The use of petroleum for liquid-transportation fuels has strained the environment and caused the global crude oil reserves to diminish. Therefore, there exists a need to replace petroleum as the primary fuel derivative. Butanol is a four-carbon alcohol that can be used to effectively replace gasoline without changing the current

The use of petroleum for liquid-transportation fuels has strained the environment and caused the global crude oil reserves to diminish. Therefore, there exists a need to replace petroleum as the primary fuel derivative. Butanol is a four-carbon alcohol that can be used to effectively replace gasoline without changing the current automotive infrastructure. Additionally, butanol offers the same environmentally friendly effects as ethanol, but possess a 23% higher energy density. Clostridium acetobutylicum is an anaerobic bacterium that can ferment renewable biomass-derived sugars into butanol. However, this fermentation becomes limited by relatively low butanol concentrations (1.3% w/v), making this process uneconomical. To economically produce butanol, the in-situ product removal (ISPR) strategy is employed to the butanol fermentation. ISPR entails the removal of butanol as it is produced, effectively avoiding the toxicity limit and allowing for increased overall butanol production. This thesis explores the application of ISPR through integration of expanded-bed adsorption (EBA) with the C. acetobutylicum butanol fermentations. The goal is to enhance volumetric productivity and to develop a semi-continuous biofuel production process. The hydrophobic polymer resin adsorbent Dowex Optipore L-493 was characterized in cell-free studies to determine the impact of adsorbent mass and circulation rate on butanol loading capacity and removal rate. Additionally, the EBA column was optimized to use a superficial velocity of 9.5 cm/min and a resin fraction of 50 g/L. When EBA was applied to a fed-batch butanol fermentation performed under optimal operating conditions, a total of 25.5 g butanol was produced in 120 h, corresponding to an average yield on glucose of 18.6%. At this level, integration of EBA for in situ butanol recovered enabled the production of 33% more butanol than the control fermentation. These results are very promising for the production of butanol as a biofuel. Future work will entail the optimization of the fed-batch process for higher glucose utilization and development of a reliable butanol recovery system from the resin.
ContributorsWiehn, Michael (Author) / Nielsen, David (Thesis advisor) / Lin, Jerry (Committee member) / Lind, Mary Laura (Committee member) / Arizona State University (Publisher)
Created2013
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Description
Post-combustion carbon capture is a viable option for reducing CO2 greenhouse gas emissions, and one potentially promising technology for this route is adsorption using chemically and physically based sorbents. A number of exceptional CO2 sorbents materials have been prepared including metal organic frameworks, zeolites, and carbon based materials. One particular

Post-combustion carbon capture is a viable option for reducing CO2 greenhouse gas emissions, and one potentially promising technology for this route is adsorption using chemically and physically based sorbents. A number of exceptional CO2 sorbents materials have been prepared including metal organic frameworks, zeolites, and carbon based materials. One particular group of capable materials are amine based solid sorbents that has shown to possess high adsorption capacities and favorable adsorption kinetics. A key variable in the synthesis of an amine based sorbent is the support which acts as the platform for the amine modification. Aerogels, due to their high porosities and surface areas, appear to be a promising support for an amine modified CO2 sorbent. Therefore, in order to develop a commercially viable CO2 sorbent, particulate aerogels manufactured by Cabot Corporation through an economical and proprietary ambient drying process were modified with amines using a variety of functionalization methods. Two methods of physical impregnation of the amino polymer TEPA were performed in order to observe the performance as well as understand the effects of how the TEPA distribution is affected by the method of introduction. Both samples showed excellent adsorption capacities but poor cyclic stability for lack of any covalent attachment. Furthermore the method of TEPA impregnation seems to be independent on how the polymer will be distributed in the pore space of aerogel. The last two methods utilized involved covalently attaching amino silanes to the surface silanols of the aerogel. One method was performed in the liquid phase under anhydrous and hydrous conditions. The materials developed through the hydrous method have much greater adsorption capacities relative to the anhydrous sample as a result of the greater amine content present in the hydrous sample. Water is another source of silylation where additional silanes can attach and polymerize. These samples also possessed stable cyclic stability after 100 adsorption/regeneration cycles. The other method of grafting was performed in the gas phase through ALD. These samples possessed exceptionally high amine efficiencies and levels of N content without damaging the microstructure of the aerogel in contrast to the liquid phase grafted sorbents.
ContributorsLinneen, Nick (Author) / Lin, Jerry (Thesis advisor) / Pfeffer, Robert (Thesis advisor) / Lind, Mary (Committee member) / Rege, Kaushal (Committee member) / Nielsen, David (Committee member) / Anderson, James (Committee member) / Arizona State University (Publisher)
Created2014
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Description
This dissertation presents a systematic study of the sorption mechanisms of hydrophobic silica aerogel (Cabot Nanogel®) granules for oil and volatile organic compounds (VOCs) in different phases. The performance of Nanogel for removing oil from laboratory synthetic oil-in-water emulsions and real oily wastewater, and VOCs from their aqueous solution, in

This dissertation presents a systematic study of the sorption mechanisms of hydrophobic silica aerogel (Cabot Nanogel®) granules for oil and volatile organic compounds (VOCs) in different phases. The performance of Nanogel for removing oil from laboratory synthetic oil-in-water emulsions and real oily wastewater, and VOCs from their aqueous solution, in both packed bed (PB) and inverse fluidized bed (IFB) modes was also investigated. The sorption mechanisms of VOCs in the vapor, pure liquid, and aqueous solution phases, free oil, emulsified oil, and oil from real wastewater on Nanogel were systematically studied via batch kinetics and equilibrium experiments. The VOC results show that the adsorption of vapor is very slow due to the extremely low thermal conductivity of Nanogel. The faster adsorption rates in the liquid and solution phases are controlled by the mass transport, either by capillary flow or by vapor diffusion/adsorption. The oil results show that Nanogel has a very high capacity for adsorption of pure oils. However, the rate for adsorption of oil from an oil-water emulsion on the Nanogel is 5-10 times slower than that for adsorption of pure oils or organics from their aqueous solutions. For an oil-water emulsion, the oil adsorption capacity decreases with an increasing proportion of the surfactant added. An even lower sorption capacity and a slower sorption rate were observed for a real oily wastewater sample due to the high stability and very small droplet size of the wastewater. The performance of Nanogel granules for removing emulsified oil, oil from real oily wastewater, and toluene at low concentrations in both PB and IFB modes was systematically investigated. The hydrodynamics characteristics of the Nanogel granules in an IFB were studied by measuring the pressure drop and bed expansion with superficial water velocity. The density of the Nanogel granules was calculated from the plateau pressure drop of the IFB. The oil/toluene removal efficiency and the capacity of the Nanogel granules in the PB or IFB were also measured experimentally and predicted by two models based on equilibrium and kinetic batch measurements of the Nanogel granules.
ContributorsWang, Ding (Author) / Lin, Jerry Y.S. (Thesis advisor) / Pfeffer, Robert (Thesis advisor) / Westerhoff, Paul (Committee member) / Nielsen, David (Committee member) / Lind, Mary Laura (Committee member) / Arizona State University (Publisher)
Created2011
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Description
In our modern world the source of for many chemicals is to acquire and refine oil. This process is becoming an expensive to the environment and to human health. Alternative processes for acquiring the final product have been developed but still need work. One product that is valuable is butanol.

In our modern world the source of for many chemicals is to acquire and refine oil. This process is becoming an expensive to the environment and to human health. Alternative processes for acquiring the final product have been developed but still need work. One product that is valuable is butanol. The normal process for butanol production is very intensive but there is a method to produce butanol from bacteria. This process is better because it is more environmentally safe than using oil. One problem however is that when the bacteria produce too much butanol it reaches the toxicity limit and stops the production of butanol. In order to keep butanol from reaching the toxicity limit an adsorbent is used to remove the butanol without harming the bacteria. The adsorbent is a mesoporous carbon powder that allows the butanol to be adsorbed on it. This thesis explores different designs for a magnetic separation process to extract the carbon powder from the culture.
ContributorsChabra, Rohin (Author) / Nielsen, David (Thesis director) / Torres, Cesar (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2015-05
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Description
The goals of the styrene oxide adsorption experiments were to develop reliable isotherms of styrene oxide onto Dowex Optipore L-493 resin and onto mesoporous carbon adsorbents, in addition to determining the ideal conditions for styrene oxide production from E. coli. Adsorption is an effective means of separation used in industry

The goals of the styrene oxide adsorption experiments were to develop reliable isotherms of styrene oxide onto Dowex Optipore L-493 resin and onto mesoporous carbon adsorbents, in addition to determining the ideal conditions for styrene oxide production from E. coli. Adsorption is an effective means of separation used in industry to separate compounds, often organics from air and water. Styrene oxide adsorption runs without E. coli were conducted at concentrations ranging from 0.15 to 3.00 g/L with resin masses ranging from 0.1 to 0.5 g of Dowex Optipore L-493 and 0.5 to 0.75 g of mesoporous carbon adsorbent. Runs were conducted on a shake plate operating at 80 rpm for 24 hours at ambient temperature. Isotherms were developed from the results and then adsorption experiments with E. coli and L-493 were performed. Runs were conducted at glucose concentrations ranging from 20-40 g/L and resin masses of 0.100 g to 0.800 g. Samples were incubated for 72 hours and styrene oxide production was measured using an HPLC device. Specific loading values reached up to 0.356 g/g for runs without E. coli and nearly 0.003 g of styrene oxide was adsorbed by L-493 during runs with E. coli. Styrene oxide production was most effective at low resin masses and medium glucose concentrations when produced by E. coli.
ContributorsHsu, Joshua (Co-author) / Oremland, Zachary (Co-author) / Nielsen, David (Thesis director) / Staggs, Kyle (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor) / School of Sustainability (Contributor)
Created2014-05
Description

Using DFT calculations and GAMESS computational software, porphine and its derivatives were analyzed for unique sites to accept the adsorbates As(III), As(V) and P(V) in order to compare resulting adsorption energies and determine if any of these molecules prefer arsenic oxyanions over phosphate. Pure porphine preferred As(III) over P(V) with

Using DFT calculations and GAMESS computational software, porphine and its derivatives were analyzed for unique sites to accept the adsorbates As(III), As(V) and P(V) in order to compare resulting adsorption energies and determine if any of these molecules prefer arsenic oxyanions over phosphate. Pure porphine preferred As(III) over P(V) with a resulting adsorption energy of -0.7974 eV. Of the functionalized porphyrins tested, carboxyl porphyrin preferred As(V) over P(V) with a total adsorption energy of -0.7345 eV. Ethyl, methyl, chlorine and amino porphyrin all preferred As(III), with energies of -0.7934, -0.8239, -0.7602, and -0.8508 eV, respectively. Of the metalated porphyrins tested, copper and vanadium porphyrin preferred As(V) over P(V) with adsorption energies of -0.7645 and -2.0915 eV. Chromium, iron and magnesium porphyrin all preferred As(III) over P(V) with energies of -0.5993, -1.4539, and - 1.0790 eV, respectively.

ContributorsKusbel, Ashley (Author) / Muhich, Christopher (Thesis director) / Jin, Kailong (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2023-05
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Description
The objective of this research was to develop Aluminophosphate-five (AlPO4-5, AFI) zeolite adsorbents for efficient oxygen removal from a process stream to support an on-going Department of Energy (DOE) project on solar energy storage. A molecular simulation study predicted that substituted AlPO4-5 zeolite can adsorb O2 through a weak chemical

The objective of this research was to develop Aluminophosphate-five (AlPO4-5, AFI) zeolite adsorbents for efficient oxygen removal from a process stream to support an on-going Department of Energy (DOE) project on solar energy storage. A molecular simulation study predicted that substituted AlPO4-5 zeolite can adsorb O2 through a weak chemical bond at ambient temperature. Substituted AlPO4-5 zeolite was successfully synthesized via hydrothermal crystallization by following carefully designed procedures to tailor the zeolite for efficient O2 adsorption. Synthesized AlPO4-5 in this work included Sn/AlPO-5, Mo/AlPO-5, Pd/AlPO-5, Si/AlPO-5, Mn/AlPO-5, Ce/AlPO-5, Fe/AlPO-5, CuCe/AlPO-5, and MnSnSi/AlPO-5. While not all zeolite samples synthesized were fully characterized, selected zeolite samples were characterized by powder x-ray diffraction (XRD) for crystal structure confirmation and phase identification, and nitrogen adsorption for their pore textural properties. The Brunauer-Emmett-Teller (BET) specific surface area and pore size distribution were between 172 m2 /g - 306 m2 /g and 6Å - 9Å, respectively, for most of the zeolites synthesized. Samples of great interest to this project such as Sn/AlPO-5, Mo/AlPO-5 and MnSnSi/AlPO-5 were also characterized using x-ray photoelectron spectroscopy (XPS) and energy-dispersive x-ray spectroscopy (EDS) for elemental analysis, scanning electron microscopy (SEM) for morphology and particle size estimation, and electron paramagnetic resonance (EPR) for nature of adsorbed oxygen. Oxygen and nitrogen adsorption experiments were carried out in a 3-Flex adsorption apparatus (Micrometrics) at various temperatures (primarily at 25℃) to determine the adsorption properties of these zeolite samples as potential adsorbents for oxygen/nitrogen separation. Experiments showed that some of the zeolite samples adsorb little-to-no oxygen and nitrogen at 25℃, while other zeolites such as Sn/AlPO-5, Mo/AlPO-5, and MnSnSi/AlPO-5 adsorb decent but inconsistent amounts of oxygen with the highest observed values of about 0.47 mmol/ g, 0.56 mmol/g, and 0.84 mmol/ g respectively. The inconsistency in adsorption is currently attributed to non-uniform doping of the zeolites, and these findings validate that some substituted AlPO4-5 zeolites are promising adsorbents. However, more investigations are needed to verify the causes of this inconsistency to develop a successful AlPO4-5 zeolite-based adsorbent for oxygen/nitrogen separation.
ContributorsBuyinza, Allan Smith (Author) / Deng, Shuguang (Thesis advisor) / Varman, Arul M (Committee member) / Jin, Kailong (Committee member) / Arizona State University (Publisher)
Created2021