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1.
Lively, Ryan P.
Hollow fiber sorbents for post-combustion CO₂ capture.
Degree: PhD, Chemical Engineering, 2011, Georgia Tech
URL: http://hdl.handle.net/1853/43758 
► As concerns mount about the rise in atmospheric CO₂ concentrations, many different routes to reduce CO₂ emissions have been proposed. Of these, post-combustion CO₂ capture…
(more)
▼ As concerns mount about the rise in atmospheric CO₂ concentrations, many different routes to reduce CO₂ emissions have been proposed. Of these, post-combustion CO₂ capture from coal-fired power stations is often the most controversial, as the CO₂ capture system will remove generating capacity from the grid whereas many of the other solutions involve increasing the generating capacity of the grid with low CO₂-emission plants. Despite this, coal-fired power stations represent a major point source for CO₂ emissions, and if a consensus is reached on the need to reduce CO₂ emissions, a low-cost method for capturing and storing the CO₂ released by these power plants needs to be developed. The overarching goal of this research is to design and develop a novel hollow fiber sorbent system for post-combustion CO₂ capture.
To achieve this goal, three objectives were developed to guide this research: i) develop a conceptual framework for hollow fiber sorbents that focuses on the energetic requirements of the system, ii) demonstrate that hollow fiber sorbents can be created, and a defect-free lumen layer can be made, iii) perform proof-of-concept CO₂ sorption experiments to confirm the validity of this approach to CO₂ capture. Each of these objectives is addressed in the body of this dissertation.
Work on the first objective showed that fiber sorbents can combine the energetic advantages of a physi-/chemi-sorption process utilizing a solid sorbent while mitigating the process deficiencies associated with using solid sorbents in a typical packed bed. All CO₂ capture technologies – including fiber sorbents – were shown to be highly parasitic to a host power plant in the absence of effective heat integration. Fiber sorbents have the unique advantage that heat integration is enabled most effectively by the hollow fiber morphology: the CO₂-sorbing fibers can behave as "adsorbing heat exchangers."
A dry-jet, wet-quench based hollow fiber spinning process was utilized to spin fibers that were 75wt% solid sorbent (zeolite 13X) and 25wt% support polymer (cellulose acetate). The spinning process was consistent and repeatable, allowing for production of large quantities of fibers. The fibers were successfully post-treated with an emulsion-based polymer (polyvinylidene chloride) to create a defect-free lumen side coating that was an excellent barrier to both water and gas permeation. A film study was conducted to elucidate the dominant factors in the formation of a defect-free film, and these factors were used for the creation of defect-free lumen layers. The work discussed in this thesis shows that the second objective of this work was definitively achieved.
For the third objective, sorption experiments conducted on the fiber sorbents indicated that the fiber sorbents CO₂ uptake is simply a weighted average of the support material CO₂ uptake and the solid sorbent uptake. Furthermore, kinetic experiments indicate that CO₂ access to the sorbents is not occluded noticeably by the polymer matrix. Using the fiber sorbents in…
Advisors/Committee Members: William J. Koros (Committee Chair), Christopher W.. Jones (Committee Member), John D. Muzzy (Committee Member), Ronald R. Chance (Committee Member), Ronald W. Rousseau (Committee Member).
Subjects/Keywords: Chromatography; Lumen layer; CO₂ capture; Fiber sorbents; Chromatographic analysis; Sorbents; Adsorption; Gases Absorption and adsorption
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APA (6th Edition):
Lively, R. P. (2011). Hollow fiber sorbents for post-combustion CO₂ capture. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/43758
Chicago Manual of Style (16th Edition):
Lively, Ryan P. “Hollow fiber sorbents for post-combustion CO₂ capture.” 2011. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/43758.
MLA Handbook (7th Edition):
Lively, Ryan P. “Hollow fiber sorbents for post-combustion CO₂ capture.” 2011. Web. 05 Mar 2021.
Vancouver:
Lively RP. Hollow fiber sorbents for post-combustion CO₂ capture. [Internet] [Doctoral dissertation]. Georgia Tech; 2011. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/43758.
Council of Science Editors:
Lively RP. Hollow fiber sorbents for post-combustion CO₂ capture. [Doctoral Dissertation]. Georgia Tech; 2011. Available from: http://hdl.handle.net/1853/43758
2.
Goteti, Anil Chaitanya.
Experimental investigation and systems modeling of fractional catalytic pyrolysis of pine.
Degree: MS, Chemical Engineering, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/42844
► The fractional catalytic pyrolysis of pine was studied both experimentally and through models. A preliminary stage economic analysis was conducted for a wood chip pyrolysis…
(more)
▼ The fractional catalytic pyrolysis of pine was studied both experimentally and through models. A preliminary stage economic analysis was conducted for a wood chip pyrolysis facility operating at a feed rate of 2000 wet ton/day for producing bio-oil.
In the experimental study, multiple grams of bio oil were produced in a single run to facilitate the more extensive characterization of the oil produced from pyrolysis of biomass impregnated with different catalysts. Two reactors configurations, a screw extruder and a tubular pyrolysis reactor, were explored to perform fractional catalytic pyrolysis of biomass. The main aim of performing a wood pyrolysis reaction in a modified screw extruder is to facilitate the simultaneous collection of bio-oil produced from staged temperature pyrolysis of three main components of wood, cellulose, hemicellulose and lignin, at a reasonable scale. Apart from complete characterization of bio-oil, this will enable us to study the effect of various selected catalysts on the quality of bio-oil and the percentage of char produced, and the influence of process parameters on chemical composition of the pyrolysis oils. These experiments were later performed in a tubular pyrolysis reactor due to the difficulty of making different parts of the extruder work well together. The goal of these experiments is to produce bio-oil in multiple grams from fractional catalytic pyrolysis of wood. This will enable us to study the effect of catalyst on the chemical composition of the oil and percentage of char produced.
In the modeling studies, a model of an auger reactor comprised of three different zones run at different temperatures to facilitate the collection of oil from pyrolysis of three major components of wood, namely cellulose, hemicelluloses and lignin, was developed. The effect of residence time distribution (RTD), and zone temperatures based on kinetic models on the yield of products was studied. Sensitivity of the Arrhenius rate constants calculated from synthetic data with respect to small variations in process parameters was evaluated.
In the economic analysis of a wood chip pyrolysis facility, mass and energy calculations were performed based on a feed rate of 2000 wet tons/day of wood chips to the dryer. The cost of bio-oil at 10% return on investment was proposed and the sensitivity of the selling price of bio-oil with respect to capital and operating costs was analyzed.
The experimental study will serve as a benchmark in exploring the above mentioned reactor configurations further. Alkali metal carbonates were used to study the quality of oil produced from pine pyrolysis. It was established that these catalysts, when added in the same molar ratio basis, increase the percentage of char. However, complete characterization of these oils for different catalysts needs to be done.
Systems modeling of pyrolysis in an auger reactor established that the kinetic parameters (depending on experimental set up) and the RTD (Residence Time Distribution) parameters play a crucial role in…
Advisors/Committee Members: Matthew J. Realff (Committee Chair), John D. Muzzy (Committee Co-Chair), Christopher W. Jones (Committee Member), J. Rhett Mayor (Committee Member), Pradeep K. Agrawal (Committee Member).
Subjects/Keywords: Pyrolysis; Catalytic pyrolysis; Pyrolysis of pine; Fast pyrolysis; Chemical reactions; Bioorganic chemistry; Biomass energy
…of operation. There is a twin
screw extruder at Georgia Tech which was acquired to perform…
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APA (6th Edition):
Goteti, A. C. (2010). Experimental investigation and systems modeling of fractional catalytic pyrolysis of pine. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/42844
Chicago Manual of Style (16th Edition):
Goteti, Anil Chaitanya. “Experimental investigation and systems modeling of fractional catalytic pyrolysis of pine.” 2010. Masters Thesis, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/42844.
MLA Handbook (7th Edition):
Goteti, Anil Chaitanya. “Experimental investigation and systems modeling of fractional catalytic pyrolysis of pine.” 2010. Web. 05 Mar 2021.
Vancouver:
Goteti AC. Experimental investigation and systems modeling of fractional catalytic pyrolysis of pine. [Internet] [Masters thesis]. Georgia Tech; 2010. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/42844.
Council of Science Editors:
Goteti AC. Experimental investigation and systems modeling of fractional catalytic pyrolysis of pine. [Masters Thesis]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/42844
3.
Mu, Bin.
Synthesis and gas adsorption study of porous metal-organic framework materials.
Degree: PhD, Chemical Engineering, 2011, Georgia Tech
URL: http://hdl.handle.net/1853/41097
► Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) have become the focus of intense study over the past decade due to their potential for advancing…
(more)
▼ Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) have become the focus of intense study over the past decade due to their potential for advancing a variety of applications including air purification, gas storage, adsorption separations, catalysis, gas sensing, drug delivery, and so on. These materials have some distinct advantages over traditional porous materials such as the well-defined structures, uniform pore sizes, chemically functionalized sorption sites, and potential for post-synthetic modification, etc. Thus, synthesis and adsorption studies of porous MOFs have increased substantially in recent years. Among various prospective applications, air purification is one of the most immediate concerns, which has urgent requirements to improve current nuclear, biological, and chemical (NBC) filters involving commercial and military purposes. Thus, the major goal of this funded project is to search, synthesize, and test these novel hybrid porous materials for adsorptive removal of toxic industrial chemicals (TICs) and chemical warfare agents (CWAs), and to install the benchmark for new-generation NBC filters. The objective of this study is three-fold: (i) Advance our understanding of coordination chemistry by synthesizing novel MOFs and characterizing these porous coordination polymers; (ii) Evaluate porous MOF materials for gas-adsorption applications including CO2 capture, CH4 storage, other light gas adsorption and separations, and examine the chemical and physical properties of these solid adsorbents including thermal stability and heat capacity of MOFs; (iii) Evaluate porous MOF materials for next-generation NBC filter media by adsorption breakthrough measurements of TICs on MOFs, and advance our understanding about structure-property relationships of these novel adsorbents.
Advisors/Committee Members: Krista S. Walton (Committee Chair), Carsten Sievers (Committee Member), Christopher W. Jones (Committee Member), Seth Marder (Committee Member), William J. Koros (Committee Member).
Subjects/Keywords: Nanoporous materials; Metal-organic frameworks; Coordination polymers; Adsorption engineering; Gases Purification; Adsorption; Separation (Technology)
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APA (6th Edition):
Mu, B. (2011). Synthesis and gas adsorption study of porous metal-organic framework materials. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/41097
Chicago Manual of Style (16th Edition):
Mu, Bin. “Synthesis and gas adsorption study of porous metal-organic framework materials.” 2011. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/41097.
MLA Handbook (7th Edition):
Mu, Bin. “Synthesis and gas adsorption study of porous metal-organic framework materials.” 2011. Web. 05 Mar 2021.
Vancouver:
Mu B. Synthesis and gas adsorption study of porous metal-organic framework materials. [Internet] [Doctoral dissertation]. Georgia Tech; 2011. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/41097.
Council of Science Editors:
Mu B. Synthesis and gas adsorption study of porous metal-organic framework materials. [Doctoral Dissertation]. Georgia Tech; 2011. Available from: http://hdl.handle.net/1853/41097
4.
Donaldson, Megan Elizabeth.
Development and application of novel solvents for sustainable reactions and separations.
Degree: PhD, Chemical Engineering, 2008, Georgia Tech
URL: http://hdl.handle.net/1853/24749
► Environmentally benign alternatives for solvents and catalysts are essential for the development of sustainable chemical processes. Toward this end, we focused our research on the…
(more)
▼ Environmentally benign alternatives for solvents and catalysts are essential for the development of sustainable chemical processes. Toward this end, we focused our research on the design of novel solvents and catalysts that reduce the environmental impact of these important materials. In this research, we develop switchable and tunable systems that couple reaction and separation to ease the processing requirements for product isolation and catalyst recovery. The switchable solvents use a ¡°switch¡± to transition from non-volatile, polar, aprotic solvents to volatile gases that can be easily separated. This allows us to facilitate reactions within the solvent and then enable easy separation through activation of the switch. We have used these materials for numerous reaction applications, including difficult reactions involving highly immiscible compounds. We also extended the work to acid-catalyzed reactions, in which we can avoid wasteful neutralization processes that are often associated with homogeneous acid catalysis. The tunable solvents use carbon dioxide pressure to ¡°tune¡± into desired solvent properties. We enable this through the dissolution of carbon dioxide into organic solvents, which generates gas-expanded liquids with solvent properties highly dependent on the carbon dioxide pressure. We can use this effect to couple homogeneous reaction with heterogeneous separation, allowing for recovery of expensive catalysts and ligands. In this work, we assess the possibilities of using liquid polyethylene glycol in the tunable systems, studying the phase behavior and industrial applications.
Advisors/Committee Members: Charles A. Eckert (Committee Chair), Charles L. Liotta (Committee Co-Chair), Christopher W. Jones (Committee Member), Facundo M. Fernandez (Committee Member), Thomas F. Fuller (Committee Member).
Subjects/Keywords: Switchable solvents; Green chemistry; Gas-expanded liquids; Phase transfer catalysis; Phase behavior; Sustainable engineering; Solvents; Green products; Sustainable engineering; Catalysts; Polyethylene glycol
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APA (6th Edition):
Donaldson, M. E. (2008). Development and application of novel solvents for sustainable reactions and separations. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/24749
Chicago Manual of Style (16th Edition):
Donaldson, Megan Elizabeth. “Development and application of novel solvents for sustainable reactions and separations.” 2008. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/24749.
MLA Handbook (7th Edition):
Donaldson, Megan Elizabeth. “Development and application of novel solvents for sustainable reactions and separations.” 2008. Web. 05 Mar 2021.
Vancouver:
Donaldson ME. Development and application of novel solvents for sustainable reactions and separations. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/24749.
Council of Science Editors:
Donaldson ME. Development and application of novel solvents for sustainable reactions and separations. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/24749
5.
Han, Jeong Woo.
Density functional theory studies for separation of enantiomers of a chiral species by enantiospecific adsorption on solid surfaces.
Degree: PhD, Chemical Engineering, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/34848
► The distinct response of biological systems to the two enantiomers of a chiral chemical has led to a large market for enantiopure pharmaceuticals and raised…
(more)
▼ The distinct response of biological systems to the two enantiomers of a chiral chemical has led to a large market for enantiopure pharmaceuticals and raised fundamental issues about the origin of biological homochirality. It is therefore important to understand the interactions of chiral molecules with chiral environments. Chiral environments associated with solid surfaces could potentially play a useful role in chirally specific chemical processing. There are a variety of routes for creating chiral solid surfaces. Surfaces of materials whose bulk crystal structure is enantiomorphic can be used as one type of chiral solid surfaces. Metal surfaces that are intrinsically chiral due to the presence of kinked surface steps provide another route for creating chiral solid surfaces. Alternatively, we can impart chirality onto surfaces by attaching irreversibly adsorbing chiral organic species on otherwise achiral surfaces. Understanding and ultimately controlling enantiospecific interactions of molecules on this kind of surfaces requires detailed insight into the adsorption geometries and energies of these complex interfaces. To tackle these issues, we performed density functional theory (DFT) calculations that have proved to be a useful tool for quantitative prediction of these effects. Besides our main topic above, we theoretically examine the effects of K atoms as a promoter coadsorbed with small molecules on Mo2C surfaces, a promising catalyst for a range of chemicals applications. Our results in this thesis provide fundamental information about these systems and demonstrate that using DFT for this purpose can be a useful means of identifying the phenomena that control chiral surface chemistry.
Advisors/Committee Members: David S. Sholl (Committee Chair), Christopher W. Jones (Committee Member), J. Carson Meredith (Committee Member), Pradeep K. Agrawal (Committee Member), Thomas M. Orlando (Committee Member).
Subjects/Keywords: Alloying; Surface; Catalyst; Chirality; Density functional theory; Quartz; Enantiomers; Chiral drugs; Density functionals; Stereochemistry
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APA (6th Edition):
Han, J. W. (2010). Density functional theory studies for separation of enantiomers of a chiral species by enantiospecific adsorption on solid surfaces. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/34848
Chicago Manual of Style (16th Edition):
Han, Jeong Woo. “Density functional theory studies for separation of enantiomers of a chiral species by enantiospecific adsorption on solid surfaces.” 2010. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/34848.
MLA Handbook (7th Edition):
Han, Jeong Woo. “Density functional theory studies for separation of enantiomers of a chiral species by enantiospecific adsorption on solid surfaces.” 2010. Web. 05 Mar 2021.
Vancouver:
Han JW. Density functional theory studies for separation of enantiomers of a chiral species by enantiospecific adsorption on solid surfaces. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/34848.
Council of Science Editors:
Han JW. Density functional theory studies for separation of enantiomers of a chiral species by enantiospecific adsorption on solid surfaces. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/34848
6.
Haldoupis, Emmanuel.
Mulitscale modeling and screening of nanoporous materials and membranes for separations.
Degree: PhD, Chemical and Biomolecular Engineering, 2013, Georgia Tech
URL: http://hdl.handle.net/1853/47669
► The very large number of distinct structures that are known for metal-organic frameworks (MOFs) and zeolites presents both an opportunity and a challenge for identifying…
(more)
▼ The very large number of distinct structures that are known for metal-organic frameworks (MOFs) and zeolites presents both an opportunity and a challenge for identifying materials with useful properties for targeted separations. In this thesis we propose a three-stage computational methodology for addressing this issue and comprehensively screening all available nanoporous materials. We introduce efficient pore size calculations as a way of discarding large number of materials, which are unsuitable for a specific separation. Materials identified as having desired geometric characteristics can be further analyzed for their infinite dilution adsorption and diffusion properties by calculating the Henry's constants and activation energy barriers for diffusion. This enables us to calculate membrane selectivity in an unprecedented scale and use these values to generate a small set of materials for which the membrane selectivity can be calculated in detail and at finite loading using well-established computational tools. We display the results of using these methods for >500 MOFs and >160 silica zeolites for spherical adsorbates at first and for small linear molecules such as CO₂ later on. In addition we also demonstrate the size of the group of materials this procedure can be applied to, by performing these calculations, for simple adsorbate molecules, for an existing library of >250,000 hypothetical silica zeolites. Finally, efficient methods are introduced for assessing the role of framework flexibility on molecular diffusion in MOFs that do not require defining a classical forcefield for the MOF. These methods combine ab initio MD of the MOF with classical transition state theory and molecular dynamics simulations of the diffusing molecules. The effects of flexibility are shown to be large for CH₄, but not for CO₂ and other small spherical adsorbates, in ZIF-8.
Advisors/Committee Members: Dr. David S. Sholl (Committee Chair), Dr. Christopher W. Jones (Committee Member), Dr. Krista S. Walton (Committee Member), Dr. Peter J. Hesketh (Committee Member), Dr. Sankar Nair (Committee Member).
Subjects/Keywords: Molecular simulations; Separations; Zeolites; Metal-organic frameworks; Nanoporous; Nanostructured materials; Membranes (Technology); Separation (Technology)
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APA (6th Edition):
Haldoupis, E. (2013). Mulitscale modeling and screening of nanoporous materials and membranes for separations. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/47669
Chicago Manual of Style (16th Edition):
Haldoupis, Emmanuel. “Mulitscale modeling and screening of nanoporous materials and membranes for separations.” 2013. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/47669.
MLA Handbook (7th Edition):
Haldoupis, Emmanuel. “Mulitscale modeling and screening of nanoporous materials and membranes for separations.” 2013. Web. 05 Mar 2021.
Vancouver:
Haldoupis E. Mulitscale modeling and screening of nanoporous materials and membranes for separations. [Internet] [Doctoral dissertation]. Georgia Tech; 2013. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/47669.
Council of Science Editors:
Haldoupis E. Mulitscale modeling and screening of nanoporous materials and membranes for separations. [Doctoral Dissertation]. Georgia Tech; 2013. Available from: http://hdl.handle.net/1853/47669
7.
Omole, Imona C.
Crosslinked polyimide hollow fiber membranes for aggressive natural gas feed streams.
Degree: PhD, Chemical Engineering, 2008, Georgia Tech
URL: http://hdl.handle.net/1853/26591
► Natural gas is one of the fastest growing primary energy sources in the world today. The increasing world demand for energy requires increased production of…
(more)
▼ Natural gas is one of the fastest growing primary energy sources in the world today. The increasing world demand for energy requires increased production of high quality natural gas. For the natural gas to be fed into the mainline gas transportation system, it must meet the pipe-line quality standards. Natural gas produced at the wellhead is usually "sub-quality" and contains various impurities such as CO2, H2S, and higher hydrocarbons, which must be removed to meet specifications.
Carbon dioxide is usually the most abundant impurity in natural gas feeds and high CO2 partial pressures in the feed can lead to plasticization, which causes loss of some methane product and may ultimately render the membrane ineffective. Moreover, the presence of highly sorbing higher hydrocarbons in the feed can further reduce membrane performance.
Covalent crosslinking has been shown to increase plasticization resistance in dense films by suppressing the degree of swelling and segmental chain mobility in the polymer, thereby preserving the selectivity of the membrane. This research focuses on extending the dense film success to asymmetric hollow fibers.
In this work, the effect of high pressure CO2 (up to 400 psia CO2 partial pressure) on CO2/CH4 mixed gas separation performance was investigated on defect-free the hollow fiber membrane at different degrees of crosslinking. All the crosslinked fibers were shown to exhibit good resistance to selectivity losses from CO2 induced plasticization, significantly more than the uncrosslinked fibers. Robust resistance of the hollow fiber membranes in the presence of toluene (a highly sorbing contaminant) was also demonstrated as the membranes showed no plasticization. Antiplasticization was found to occur in the presence of toluene feeds with the crosslinkable fibers used in this work.
Advisors/Committee Members: Dr. William J. Koros (Committee Chair), Dr. Amyn Teja (Committee Member), Dr. Christopher W. Jones (Committee Member), Dr. Haskell W. Beckham (Committee Member), Dr. Stephen J. Miller (Committee Member).
Subjects/Keywords: Membrane; Carbon dioxide; Natural gas; Hollow fiber; Polyimide; Gas separation; Gas separation membranes; High pressure (Technology); Natural gas; Crosslinked polymers
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APA (6th Edition):
Omole, I. C. (2008). Crosslinked polyimide hollow fiber membranes for aggressive natural gas feed streams. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/26591
Chicago Manual of Style (16th Edition):
Omole, Imona C. “Crosslinked polyimide hollow fiber membranes for aggressive natural gas feed streams.” 2008. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/26591.
MLA Handbook (7th Edition):
Omole, Imona C. “Crosslinked polyimide hollow fiber membranes for aggressive natural gas feed streams.” 2008. Web. 05 Mar 2021.
Vancouver:
Omole IC. Crosslinked polyimide hollow fiber membranes for aggressive natural gas feed streams. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/26591.
Council of Science Editors:
Omole IC. Crosslinked polyimide hollow fiber membranes for aggressive natural gas feed streams. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/26591
Georgia Tech
8.
Richardson, John Michael.
Distinguishing between surface and solution catalysis for palladium catalyzed C-C coupling reactions: use of selective poisons.
Degree: PhD, Chemical and Biomolecular Engineering, 2008, Georgia Tech
URL: http://hdl.handle.net/1853/22704
► This work focuses on understanding the heterogeneous/homogeneous nature of the catalytic species for a variety of immobilized metal precatalysts used for C-C coupling reactions. These…
(more)
▼ This work focuses on understanding the heterogeneous/homogeneous nature of the catalytic species for a variety of immobilized metal precatalysts used for C-C coupling reactions. These precatalysts include: (i) tethered organometallic palladium pincer complexes, (ii) an encapsulated small molecule palladium complex in a polymer matrix, (iii) mercapto-modified mesoporous silica metalated with palladium acetate, and (iv) amino-functionalized mesoporous silicas metalated with Ni(II). As part of this investigation, the use of metal scavengers as selective poisons of homogeneous catalysis is introduced and investigated as a test for distinguishing heterogeneous from homogeneous catalysis. The premise of this test is that insoluble materials functionalized with metal binding sites can be used to selectively remove soluble metal, but will not interfere with catalysis from immobilized metal. In this way the test can definitely distinguish between surface and solution catalysis of immobilized metal precatalysts.
This work investigates three different C-C coupling reactions catalyzed by the immobilized metal precatalysts mentioned above. These reactions include the Heck, Suzuki, and Kumada reactions. In all cases it is found that catalysis is solely from leached metal. Three different metal scavenging materials are presented as selective poisons that can be used to determine solution vs. surface catalysis. These selective poisons include poly(vinylpyridine), QuadrapureTM TU, and thiol-functionalized mesoporous silica. The results are contrasted against the current understanding of this field of research and subtleties of tests for distinguishing homogeneous from heterogeneous catalysis are presented and discussed.
Advisors/Committee Members: Dr. Christopher W. Jones (Committee Chair), Dr. E. Kent Barefield (Committee Member), Dr. Marcus Weck (Committee Member), Dr. Pradeep Agrawal (Committee Member), Dr. Rachel Chen (Committee Member).
Subjects/Keywords: Palladium catalysis; Cross coupling reaction; Heterogeneous vs. homogeneous; Selective poisoning; Palladium catalysts; Heterogeneous catalysis; Catalysis; Catalyst poisoning
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APA (6th Edition):
Richardson, J. M. (2008). Distinguishing between surface and solution catalysis for palladium catalyzed C-C coupling reactions: use of selective poisons. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/22704
Chicago Manual of Style (16th Edition):
Richardson, John Michael. “Distinguishing between surface and solution catalysis for palladium catalyzed C-C coupling reactions: use of selective poisons.” 2008. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/22704.
MLA Handbook (7th Edition):
Richardson, John Michael. “Distinguishing between surface and solution catalysis for palladium catalyzed C-C coupling reactions: use of selective poisons.” 2008. Web. 05 Mar 2021.
Vancouver:
Richardson JM. Distinguishing between surface and solution catalysis for palladium catalyzed C-C coupling reactions: use of selective poisons. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/22704.
Council of Science Editors:
Richardson JM. Distinguishing between surface and solution catalysis for palladium catalyzed C-C coupling reactions: use of selective poisons. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/22704
Georgia Tech
9.
Nayak, Satish Prakash.
Design, Synthesis and Characterization of Multiresponsive Microgels.
Degree: PhD, Chemistry and Biochemistry, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/6845
► This thesis is geared towards using hydrogel nanoparticles in various biotechnological applications. The polymer that was used in making these nanoparticles was poly(N-isopropylacrylamide), which is…
(more)
▼ This thesis is geared towards using hydrogel nanoparticles in various biotechnological applications. The polymer that was used in making these nanoparticles was poly(N-isopropylacrylamide), which is a thermoresponsive polymer. These particles were used in making fast responsive polymer films, which can be used in optics. It was observed that the rate of deswelling increased as the concentration of the nanoparticles in the film was increased. These particles were also used in making photoresponsive materials. In this case a photoresponsive dye (malachite green) was conjugated to these nanoparticles and in presence of light of appropriate wavelength the particles undergo a phase transition. A core/shell construct was synthesized where the core was composed of degradable cross-links and the shell of composed of non-degradable cross-links. The degradable cross-linker had vicinal diols, which can be cleaved by sodium periodate. Hence after degrading the core, hollow particles were obtained. Zwitterionic particles were made by incorporating a cationic and anionic comonomer. These microgels go from a positively charged state to zwitterionic to negatively charged state on increasing the pH. One of the important potential applications for these microgels is drug delivery. Microgels were used for targeting cancer cells. Folic acid was used as the targeting ligand. The microgels were conjugated with folic acid and were able to target cells that overexpress folate receptors. In one other application core/shell microgels were made which exhibit pore-size dependent permeation of proteins.
Advisors/Committee Members: Dr. L. Andrew Lyon (Committee Chair), Dr. Christopher W. Jones (Committee Member), Dr. Jiri Janata (Committee Member), Dr. Marcus Weck (Committee Member), Dr. Nicholas V. Hud (Committee Member).
Subjects/Keywords: pNIPAm; Core/Shell; Nanoparticles; Hydrogels; Polymers; Thin films; Polymers Thermal properties; Polymers Optical properties; Nanoparticles Synthesis; Colloids
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APA (6th Edition):
Nayak, S. P. (2005). Design, Synthesis and Characterization of Multiresponsive Microgels. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/6845
Chicago Manual of Style (16th Edition):
Nayak, Satish Prakash. “Design, Synthesis and Characterization of Multiresponsive Microgels.” 2005. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/6845.
MLA Handbook (7th Edition):
Nayak, Satish Prakash. “Design, Synthesis and Characterization of Multiresponsive Microgels.” 2005. Web. 05 Mar 2021.
Vancouver:
Nayak SP. Design, Synthesis and Characterization of Multiresponsive Microgels. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/6845.
Council of Science Editors:
Nayak SP. Design, Synthesis and Characterization of Multiresponsive Microgels. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/6845
Georgia Tech
10.
Sommer, William J.
Supported catalysts, from polymers to gold nanoparticles supports.
Degree: PhD, Chemistry and Biochemistry, 2007, Georgia Tech
URL: http://hdl.handle.net/1853/16140
► In today s world, the need to limit the use of nonrenewable resources and the importance of recycling has been recognized. One important contribution of…
(more)
▼ In today s world, the need to limit the use of nonrenewable resources and the importance of recycling has been recognized. One important contribution of chemists toward the general goal of limiting their use is to find catalysts that can be reused and recycled thereby limiting the need for expensive metal precursors and metal waste. Strategies to recycle catalysts are multifold and range from the employment of soluble polymers as catalyst supports to the use of membrane-encapsulated catalyst. The use of soluble polymers as a support not only offers the advantage of being soluble under the catalytic reaction conditions but also, to be removable by changing the conditions of the surrounding media. Despite the great potential of these soluble supported catalysts, their use is very limited in today s synthesis. In addition, no set of rules have been established to guide the synthesis of efficient supported catalysts. In order to establish a tool box for the synthesis of supported catalysts, the study of several parameters such as the choice of the support and the choice and the stability of the catalyst are necessary. To establish this set of rules, a limited number of catalytic transformations, were studied. These catalytic reactions are the Heck-Mizoroki, Suzuki-Miyaura and Sonogashira coupling reactions. These transformations became fundamental for the synthesis of drugs and materials. The first and second chapters provide background information by describing and evaluating the main supports that were previously used for catalysts and the two main catalysts that are used in this thesis, the palladium pincer complex and the palladium N-heterocyclic complex. In chapter 3, the synthesis of a soluble polymer supported catalyst is described. The polymer chosen for the study is poly(norbornene), and the catalyst is a 1,3-disubstituted benzene ligand with sulfurs in the side-chains able to chelate to the metal center, better known as pincer ligand. These ligands are abbreviated by the three atoms that coordinate to the metal center, in this study, SCS. The metal used for the investigation of the activity of this supported pincer is palladium. The importance of the nature of the linkage on the stability of the Pd-SCS pincer complex has been reported in the literature, leading to the synthesis of Pd-SCS pincer complex tethered to the polymer via an ether and an amide linkage. The synthesized poly(norbornene) supported Pd-SCS pincer complexes were evaluated using the Heck transformation of iodobenzene with n-butyl acrylate. Kinetic studies and leaching tests using poly(vinyl pyridine) and mercury were carried out resulting in the conclusion that the active species during the catalysis is not the palladium pincer complex but a leached palladium (0) species. In chapter 4, Pd-PCP pincer complexes with the ether and amide tether were synthesized. Kinetic and poisoning studies were carried out resulting in a similar conclusion. Furthermore, 31P NMR experiments were conducted to investigate the unstability of the complex.…
Advisors/Committee Members: Marcus Weck (Committee Chair), Christoph J. Fahrni (Committee Member), Christopher W. Jones (Committee Member), E. Kent Barefield (Committee Member), Mostapha A. El-Sayed (Committee Member).
Subjects/Keywords: Kinetic study; Heck reaction; Coupling chemistry; Poisoning; Suzuki reaction; Catalysts; Supported catalysts; Polymers; Gold nanoparticles; Polymers Synthesis; Water-soluble polymers; Catalysts Recycling
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APA (6th Edition):
Sommer, W. J. (2007). Supported catalysts, from polymers to gold nanoparticles supports. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/16140
Chicago Manual of Style (16th Edition):
Sommer, William J. “Supported catalysts, from polymers to gold nanoparticles supports.” 2007. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/16140.
MLA Handbook (7th Edition):
Sommer, William J. “Supported catalysts, from polymers to gold nanoparticles supports.” 2007. Web. 05 Mar 2021.
Vancouver:
Sommer WJ. Supported catalysts, from polymers to gold nanoparticles supports. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/16140.
Council of Science Editors:
Sommer WJ. Supported catalysts, from polymers to gold nanoparticles supports. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/16140
Georgia Tech
11.
Mukherjee, Sanjoy.
Synthesis, Characterization, and Growth Mechanism of Single-Walled Metal Oxide Nanotubes.
Degree: PhD, Chemical Engineering, 2007, Georgia Tech
URL: http://hdl.handle.net/1853/16176
► Nanotubes have numerous potential applications in areas such as biotechnology, electronics, photonics, catalysis and separations. There are several challenges to be overcome in order to…
(more)
▼ Nanotubes have numerous potential applications in areas such as biotechnology, electronics, photonics, catalysis and separations. There are several challenges to be overcome in order to realize their potential, such as: (1) Synthesis of monodisperse (in diameter and in length) single-walled nanotubes; (2) Quantitative understanding of the mechanism of formation and growth of nanotubes; (3) Capability to engineer the nanotube size; (4) Low temperature synthesis process; and (5) Synthesis of impurity free nanotubes. Our investigation focuses on a class of metal oxide (aluminosilicate/germanate) nanotubes, which are; single walled nanotubes with monodisperse inner and outer diameters, can be synthesized in the laboratory by a low temperature (95ºC) process in mildly acidic aqueous solutions, and their formation timescales is hours, which makes it convenient as a model system to study the mechanisms of nanotube formation.
This work is focused on obtaining a qualitative and quantitative understanding of the mechanism of formation of aluminosilicate and aluminogermanate nanotubes. In order to achieve this overall objective, this thesis consists of the following aspects: (1) A systematic phenomenological study of the growth and structural properties of aluminosilicate and aluminogermanate nanotubes. The constant size and increasing nanotube concentration over the synthesis time strongly suggest that these nanotubular are assembled through self-assembly process. (II) Investigation of the mechanism of formation of single-walled aluminogermanate nanotubes provided the central phenomena underlying the formation of these nanostructures: (1) the generation (via pH control) of a precursor solution containing chemically bonded precursors, (2) the formation of amorphous nanoscale (~ 6 nm) condensates via temperature control, and (3) the self-assembly of short nanotubes from the amorphous nanoscale condensates. (III) Synthesis of mixed metal oxide (aluminosilicogermanate) nanotubes with precise control of elemental composition, diameter and length of the product nanotubes. (IV) Preliminary work towards generalization of the kinetic model developed for aluminogermanate nanotubes to a larger class of metal oxide nanotubes. It was found that the size of nanotubes is dependent on the amount of precursors that can be packed in a single ANP and in turn depends on the size of the ANP.
Advisors/Committee Members: Sankar Nair (Committee Chair), Christopher W. Jones (Committee Member), Haskell W. Beckham (Committee Member), Peter J. Hesketh (Committee Member), William J. Koros (Committee Member).
Subjects/Keywords: Imogolite; Aluminosilicate; Growth mechanism; Metal oxide; Self-assembly; Kinetic model; Nanotubes; Metallic oxides; Nanotubes Synthesis
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APA (6th Edition):
Mukherjee, S. (2007). Synthesis, Characterization, and Growth Mechanism of Single-Walled Metal Oxide Nanotubes. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/16176
Chicago Manual of Style (16th Edition):
Mukherjee, Sanjoy. “Synthesis, Characterization, and Growth Mechanism of Single-Walled Metal Oxide Nanotubes.” 2007. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/16176.
MLA Handbook (7th Edition):
Mukherjee, Sanjoy. “Synthesis, Characterization, and Growth Mechanism of Single-Walled Metal Oxide Nanotubes.” 2007. Web. 05 Mar 2021.
Vancouver:
Mukherjee S. Synthesis, Characterization, and Growth Mechanism of Single-Walled Metal Oxide Nanotubes. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/16176.
Council of Science Editors:
Mukherjee S. Synthesis, Characterization, and Growth Mechanism of Single-Walled Metal Oxide Nanotubes. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/16176
Georgia Tech
12.
Liu, Junqiang.
Development of next generation mixed matrix hollow fiber membranes for butane isomer separation.
Degree: PhD, Chemical Engineering, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/42807
► Mixed matrix hollow fiber membranes maintain the ease of processing polymers while enhancing the separation performance of the pure polymer due to inclusion of molecular…
(more)
▼ Mixed matrix hollow fiber membranes maintain the ease of processing polymers while enhancing the separation performance of the pure polymer due to inclusion of molecular sieve filler particles. This work shows the development process of high loading mixed matrix hollow fiber membranes for butane isomer separation, from material selection and engineering of polymer-sieve interfacial adhesion to mixed matrix hollow fiber spinning.
The matching of gas transport properties in polymer and zeolite is critical for forming successful mixed matrix membranes. The nC4 permeability in glassy commercial polymers such as Ultem® and Matrimid® is too low (< 0.1 Barrer) for commercial application. A group of fluorinated (6FDA) polyimides, with high nC4 permeability and nC4/iC4 selectivity, are selected as the polymer matrix. No glassy polymers can possibly match the high permeable MFI to make mixed matrix membranes with selectivity enhancement for C4s separation. Zeolite 5A, which has a nC4 permeability (~3 Barrer) and nC4/iC4 selectivity (essentially ∞), matches well with the 6FDA polymers. A 24% nC4/iC4 selectivity enhancement was achieved in mixed matrix membranes containing 6FDA-DAM and 25 wt% treated 5A particles. A more promising mixed matrix membrane contains 6FDA-DAM-DABA matrix and 5A, because of a better match of gas transport properties in polymer and zeolite.
Dual layer hollow fibers, with cellulose acetate core layer and sheath layers of 6FDA polyimides, were successfully fabricated. Successive engineering of the 6FDA sheath layer and the dense skin is needed for the challenging C4s separation, which is extremely sensitive to the integrity of the dense skin layer. The delamination-free, macrovoid-free dual layer hollow fiber membranes provide the solution for the expensive 6FDA polyimides spinning. Mixed matrix hollow fiber membranes are spun base on the platform of 6FDA/Cellulose acetate dual layer hollow fibers. Preliminary results suggest that high loading mixed matrix hollow fiber membranes for C4s is feasible. Following research is needed on the fiber spinning with well treated zeolite 5A nanoparticles.
The key aspect of this research is elucidating the three-step (sol-gel-precipitation) mechanism of sol-gel-Grignard treatment, based on which further controlling of Mg(OH)2 whisker morphologies is possible. A Mg(OH)2 nucleation process promoted by acid species is proposed to explain the heterogeneous Mg(OH)2 growing process. Different acid species were tried: 1) HCl solution, 2) AlClx species generated by dealumination process and 3) AlCl3 supported on zeolite surfaces. Acids introduced through HCl solution and dealumination are effective on commercial 5A particles to generate Mg(OH)2 whiskers in the sol-gel-Grignard treatment. Supported AlCl3 is effective on both commercial and synthesized 5A particles (150 nm-1 µm) during the sol-gel-Grignard treatment, in terms of promoting heterogeneous Mg(OH)2 whiskers formation. But the byproduct of Al(OH)3 layer separates the Mg(OH)2 whiskers from zeolite surface, and…
Advisors/Committee Members: William J. Koros (Committee Chair), Carson Meredith (Committee Member), Christopher W. Jones (Committee Member), Ronald R. Chance (Committee Member), Sankar Nair (Committee Member), Victor Breedveld (Committee Member).
Subjects/Keywords: Butane isomer separation; Mixed matrix membrane; Hollow fiber membrane; Membrane separation; Gas separation membranes; Gases Separation; Separation (Technology); Membranes (Technology); Zeolites; Polymers
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APA (6th Edition):
Liu, J. (2010). Development of next generation mixed matrix hollow fiber membranes for butane isomer separation. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/42807
Chicago Manual of Style (16th Edition):
Liu, Junqiang. “Development of next generation mixed matrix hollow fiber membranes for butane isomer separation.” 2010. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/42807.
MLA Handbook (7th Edition):
Liu, Junqiang. “Development of next generation mixed matrix hollow fiber membranes for butane isomer separation.” 2010. Web. 05 Mar 2021.
Vancouver:
Liu J. Development of next generation mixed matrix hollow fiber membranes for butane isomer separation. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/42807.
Council of Science Editors:
Liu J. Development of next generation mixed matrix hollow fiber membranes for butane isomer separation. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/42807
Georgia Tech
13.
Valenzuela, Mariefel Bayta.
Batch Aqueous-phase Reforming of Lignocellulosic Biomass for Hydrogen Production.
Degree: MS, Chemical Engineering, 2006, Georgia Tech
URL: http://hdl.handle.net/1853/11624
► Aqueous-phase reforming (APR) is reported for the first time for the production of H2 from actual biomass. The experiments are carried out in batch using…
(more)
▼ Aqueous-phase reforming (APR) is reported for the first time for the production of H2 from actual biomass. The experiments are carried out in batch using a 100mL Parr microreactor heated to 225C. In this one-pot, two-step process, acid hydrolysis is used to break down the polymeric constituents of biomass to smaller soluble molecules and these species are reformed using a Pt/Al2O3 catalyst. The experiments show that increasing the acid concentration from 1% to 5% causes more than a twelve-fold increase in H2 concentration, with hydrogen a minor product accounting for 18% of the non-condensable gas phase and CO2 as the major product. In the presence of the Pt/Al2O3 reforming catalyst, both the selectivity and yield of hydrogen in the gas phase increase. This is accompanied by a noticeable decrease in carbon monoxide production. Comparison with other feeds such as glucose, wastepaper and ethylene glycol showed that the amount of hydrogen produced from biomass is of a comparable magnitude per gram of feed, although biomass yields more hydrogen per gram of carbohydrate than either glucose or wastepaper. Baseline experiments with only the catalysts in the absence of any biomass show no increase in the reactor system pressure when only water and helium are present, indicating that the observed hydrogen produced is sourced form the biomass.
Advisors/Committee Members: Dr. Christopher W. Jones (Committee Co-Chair), Dr. Pradeep K. Agrawal (Committee Co-Chair), Dr. Howard "Jeff" Empie (Committee Member), Dr. Sujit Banerjee (Committee Member).
Subjects/Keywords: XPS; Hydrogen chemisorption; Waste paper; Bioenergy; Pt/Al2O3; Glucose; H2SO4; Water-gas shift; Hydrogen as fuel; Biomass energy; Chemisorption
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APA (6th Edition):
Valenzuela, M. B. (2006). Batch Aqueous-phase Reforming of Lignocellulosic Biomass for Hydrogen Production. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/11624
Chicago Manual of Style (16th Edition):
Valenzuela, Mariefel Bayta. “Batch Aqueous-phase Reforming of Lignocellulosic Biomass for Hydrogen Production.” 2006. Masters Thesis, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/11624.
MLA Handbook (7th Edition):
Valenzuela, Mariefel Bayta. “Batch Aqueous-phase Reforming of Lignocellulosic Biomass for Hydrogen Production.” 2006. Web. 05 Mar 2021.
Vancouver:
Valenzuela MB. Batch Aqueous-phase Reforming of Lignocellulosic Biomass for Hydrogen Production. [Internet] [Masters thesis]. Georgia Tech; 2006. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/11624.
Council of Science Editors:
Valenzuela MB. Batch Aqueous-phase Reforming of Lignocellulosic Biomass for Hydrogen Production. [Masters Thesis]. Georgia Tech; 2006. Available from: http://hdl.handle.net/1853/11624
Georgia Tech
14.
Kim, Yeu Chun.
Transdermal Drug Delivery Enhanced by Magainin Peptide.
Degree: PhD, Chemical Engineering, 2007, Georgia Tech
URL: http://hdl.handle.net/1853/19738
► The world-wide transdermal drug delivery market is quite large, but only a small number of agents have FDA approval. The primary reason for such limited…
(more)
▼ The world-wide transdermal drug delivery market is quite large, but only a small number of agents have FDA approval. The primary reason for such limited development is the difficulty in permeating the stratum corneum layer of human skin.
In our study, we developed a novel percutaneous delivery enhancing approach. Magainin peptide was previously shown to disrupt vesicles from stratum corneum lipid components and this ability of magainin allows us to propose that magainin can increase skin permeability. Therefore, we tested the hypothesis that magainin, a pore-forming peptide, can increase skin permeability by disrupting stratum corneum lipid structure and that magainin¡¯s enhancement requires co-administration of a surfactant chemical enhancer to increase magainin penetration into the skin. In support of these hypotheses, synergistic enhancement of transdermal permeation can be observed with magainin peptide in combination of N-lauroyl sarcosine (NLS) in 50% ethanol-PBS solution. The exposure to NLS in 50% ethanol solution increased in vitro skin permeability to fluorescein 15 fold and the addition of magainin synergistically increased skin permeability 47 fold. In contrast, skin permeability was unaffected by exposure to magainin without co-enhancement by NLS-ethanol.
To elucidate the mechanism of this synergistic effect, several characterization methods such as differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction were applied. These analyses showed that NLS-ethanol disrupted stratum corneum lipid structure and that the combination of magainin and NLS-ethanol disrupted stratum corneum lipids even further. Furthermore, confocal microscopy showed that magainin in the presence of NLS-ethanol penetrated deeply and extensively into stratum corneum, whereas magainin alone penetrated poorly into the skin. Together, these data suggest that NLS-ethanol increased magainin penetration into stratum corneum, which further increased stratum corneum lipid disruption and skin permeability.
Finally, skin permeability was enhanced by changing the charge of magainin peptide via pH change. We modulated pH from 5 to 11 to change the magainin charge from positive to neutral, which decreased skin permeability to a negatively charged fluorescein and increased skin permeability to a positively charged granisetron. This suggests that an attractive interaction between the drug and magainin peptide improves transdermal flux.
Advisors/Committee Members: Mark R. Prausnitz (Committee Chair), Peter J. Ludovice (Committee Co-Chair), Ajay K. Banga (Committee Member), Christopher W. Jones (Committee Member), Ronald W. Rousseau (Committee Member), William J. Koros (Committee Member).
Subjects/Keywords: pH; Ethanol; N-lauroyl sarcosine; Magainin; Antimicrobial peptide; Stratum corneum; Chemical enhancer; Transdermal drug delivery; Drug delivery systems; Transdermal medication; Peptide drugs; Skin; Permeability
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APA (6th Edition):
Kim, Y. C. (2007). Transdermal Drug Delivery Enhanced by Magainin Peptide. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/19738
Chicago Manual of Style (16th Edition):
Kim, Yeu Chun. “Transdermal Drug Delivery Enhanced by Magainin Peptide.” 2007. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/19738.
MLA Handbook (7th Edition):
Kim, Yeu Chun. “Transdermal Drug Delivery Enhanced by Magainin Peptide.” 2007. Web. 05 Mar 2021.
Vancouver:
Kim YC. Transdermal Drug Delivery Enhanced by Magainin Peptide. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/19738.
Council of Science Editors:
Kim YC. Transdermal Drug Delivery Enhanced by Magainin Peptide. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/19738
Georgia Tech
15.
Hillock, Alexis Maureen Wrenn.
Crosslinkable Polyimide Mixed Matrix Membranes for Natural Gas Purification.
Degree: PhD, Chemical Engineering, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/13933
► Crosslinkable mixed matrix membranes represent an attractive technology that promises both outstanding separation properties and swelling resistance for the purification of natural gas. This approach…
(more)
▼ Crosslinkable mixed matrix membranes represent an attractive technology that promises both outstanding separation properties and swelling resistance for the purification of natural gas. This approach relies upon dispersal of a CO2/CH4 size-discriminating zeolite in a crosslinkable polymer, which is resistant to CO2 swelling when crosslinked. The resulting membrane has the potential to separate CO2 from CH4 more effectively than traditional pure polymer membranes, while also providing needed membrane stability in the presence of aggressive CO2-contaminated natural gas streams. Control studies are conducted using the pure crosslinkable polymer to observe the separation properties and swelling resistance. Initial crosslinkable mixed matrix membrane experiments are then performed and result in an increase in membrane productivity, instead of the expected increase in selectivity. Traditionally, this is caused by material incompatibility at the polymer/zeolite interface, so the crosslinkable mixed matrix membranes are characterized to examine this issue. During the material characterization, a new non-ideal transport phenomenon is discovered in the zeolite phase. A model is developed to better understand the transport and predict subsequent experimental results. Once the independent materials are proven to be viable, crosslinkable mixed matrix membranes that show enhancements in both efficiency and productivity and exhibit stability in the presence of aggressive CO2 feeds are created.
Advisors/Committee Members: Dr. William J. Koros (Committee Chair), Dr. Christopher W. Jones (Committee Member), Dr. Haskell W. Beckham (Committee Member), Dr. Ronald W. Rousseau (Committee Member), Dr. Stephen J. Miller (Committee Member).
Subjects/Keywords: Crosslinked polyimide; Gas separation; Natural gas purification; Zeolite mesoporosity; Mixed matrix
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APA (6th Edition):
Hillock, A. M. W. (2005). Crosslinkable Polyimide Mixed Matrix Membranes for Natural Gas Purification. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/13933
Chicago Manual of Style (16th Edition):
Hillock, Alexis Maureen Wrenn. “Crosslinkable Polyimide Mixed Matrix Membranes for Natural Gas Purification.” 2005. Doctoral Dissertation, Georgia Tech. Accessed March 05, 2021.
http://hdl.handle.net/1853/13933.
MLA Handbook (7th Edition):
Hillock, Alexis Maureen Wrenn. “Crosslinkable Polyimide Mixed Matrix Membranes for Natural Gas Purification.” 2005. Web. 05 Mar 2021.
Vancouver:
Hillock AMW. Crosslinkable Polyimide Mixed Matrix Membranes for Natural Gas Purification. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Mar 05].
Available from: http://hdl.handle.net/1853/13933.
Council of Science Editors:
Hillock AMW. Crosslinkable Polyimide Mixed Matrix Membranes for Natural Gas Purification. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/13933
. 
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