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Georgia Tech
1.
Dumont, George Pierre, Jr.
The use of carbonation and fractional evaporative crystallization in the pretreatment of Hanford nuclear wastes.
Degree: MS, Chemical Engineering, 2007, Georgia Tech
URL: http://hdl.handle.net/1853/24716 
► The purpose of this work was to explore the use of fractional evaporative crystallization as a technology that can be used to separate medium-curie waste…
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▼ The purpose of this work was to explore the use of fractional evaporative crystallization as a technology that can be used to separate medium-curie waste from the Hanford Site tank farms into a high-curie waste stream, which can be sent to a Waste Treatment and Immobilization Plant (WTP), and a low-curie waste stream, which can be sent to Bulk Vitrification. Experimental semi-batch crystallizations of sodium salts from simulant solutions of double-shell tank (DST) feed demonstrated that the recovered crystalline product met the purity requirement for exclusion of cesium and nearly met the requirement on sodium recovery.
Batch fractional evaporative crystallization involves the removal of multiple solutes from a feed solution by the progressive achievement of supersaturation (through evaporation) and concomitant nucleation and growth of each species. The slurry collected from each of these crystallization stages was collected and introduced to filtration and washing steps. The product crystals obtained after washing were sampled for analysis by polarized light microscopy (PLM), dried, and sieved. The PLM results aided in identification of species crystallized in each stage.
Carbonation was used as a supplemental method to evaporative crystallization in order to increase the sodium recovery in DST experiments. Carbonation was necessary due to the high aluminum ion concentration in the solution, which leads to formation of a viscous gel during evaporation. This gel was avoided by reacting carbon dioxide with hydroxyl ions, which modified the system behavior. Through two stages of carbonation, each followed by evaporation, the effect of carbonation on sodium recovery was demonstrated.
Advisors/Committee Members: Dr. Ronald W. Rousseau (Committee Chair), Dr. Amyn S, Teja (Committee Member), Dr. Wm. James Frederick Jr. (Committee Member).
Subjects/Keywords: Hanford waste treatment; Polarized light microscopy; Fractional crystallization; Filtration and crystal washing techniques; Aluminum-based gels; Evaporative crystallization; Multi-salt crystallization; Hanford Site (Wash.); Crystallization; Separation (Technology); Evaporation
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APA (6th Edition):
Dumont, George Pierre, J. (2007). The use of carbonation and fractional evaporative crystallization in the pretreatment of Hanford nuclear wastes. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/24716
Chicago Manual of Style (16th Edition):
Dumont, George Pierre, Jr. “The use of carbonation and fractional evaporative crystallization in the pretreatment of Hanford nuclear wastes.” 2007. Masters Thesis, Georgia Tech. Accessed January 20, 2021.
http://hdl.handle.net/1853/24716.
MLA Handbook (7th Edition):
Dumont, George Pierre, Jr. “The use of carbonation and fractional evaporative crystallization in the pretreatment of Hanford nuclear wastes.” 2007. Web. 20 Jan 2021.
Vancouver:
Dumont, George Pierre J. The use of carbonation and fractional evaporative crystallization in the pretreatment of Hanford nuclear wastes. [Internet] [Masters thesis]. Georgia Tech; 2007. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/1853/24716.
Council of Science Editors:
Dumont, George Pierre J. The use of carbonation and fractional evaporative crystallization in the pretreatment of Hanford nuclear wastes. [Masters Thesis]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/24716
Georgia Tech
2.
Ozkan, Ibrahim Ali.
Thermodynamic model for associating polymer solutions.
Degree: PhD, Chemical Engineering, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/5115
► Polymer solutions in which there are strong specific interactions between the polymer and the solvent are of interest in a number of biological applications. Of…
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▼ Polymer solutions in which there are strong specific interactions between the polymer and the solvent are of interest in a number of biological applications. Of particular interest are polymer solutions in which supercritical carbon dioxide (CO2) is the solvent, because polymer processing with CO2 is an important application of green chemistry. Unfortunately, experimental data on the phase behavior of polymer - CO2 systems are relatively scarce, as are models that describe the phase behavior of such systems. The focus of this research is therefore on developing a thermodynamic model based on lattice theory for calculating phase behavior of high pressure polymer solutions with specific intermolecular interactions.
A new model, termed the LELAC (Lattice-based Extended Liquid Activity Coefficient) model is proposed based on the gART-L model of Sukhadia and Variankaval. The new model incorporates the compressibility effect at high pressures. The parameters of the model are (1) the equilibrium constant for association between a polymer segment and a solvent, (2) the specific interaction energy between a polymer segment and a solvent, and (3) the dispersion interaction energy. The dispersion interaction energy is calculated using Regular Solution Theory and therefore depends on the pure component properties. One or both of the remaining parameters is obtained from independent measurements such as FT- IR spectra. Alternatively, the two parameters can be obtained by fitting data.
Cloud point curves of polymer - CO2 systems have been successfully correlated (1.3 % error) with the new model. Also, using fitted parameters from cloud point data, the sorption behavior of CO2 in polymers has been predicted. The polymer investigated include PBMA, PVAc and Polyacrylates. Comparison of cloud points with those obtained using the SAFT model revealed that the new model performs better than the SAFT model (3.6% error) with two adjustable parameters.
The use of FT-IR to investigate interactions between CO2 and a number of polymers has been studied. The results confirm that complexes are formed between CO2 and PMMA, PEMA, PBMA, PVMK, and PVAc. A complex of PVC and CO2 is reported and a new mechanism involving a carbon oxygen triple bond is postulated for this system.
Advisors/Committee Members: Dr. Amyn S. Teja (Committee Chair), Dr. J. Carson Meredith (Committee Member), Dr. Peter J. Ludovice (Committee Member), Dr. Thomas H. Sanders (Committee Member), Dr. William J. Koros (Committee Member).
Subjects/Keywords: Modeling; Association; Polymer solutions; Thermodynamics; Thermochemistry; Polymer solutions; Chemical models
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APA (6th Edition):
Ozkan, I. A. (2004). Thermodynamic model for associating polymer solutions. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/5115
Chicago Manual of Style (16th Edition):
Ozkan, Ibrahim Ali. “Thermodynamic model for associating polymer solutions.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 20, 2021.
http://hdl.handle.net/1853/5115.
MLA Handbook (7th Edition):
Ozkan, Ibrahim Ali. “Thermodynamic model for associating polymer solutions.” 2004. Web. 20 Jan 2021.
Vancouver:
Ozkan IA. Thermodynamic model for associating polymer solutions. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/1853/5115.
Council of Science Editors:
Ozkan IA. Thermodynamic model for associating polymer solutions. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/5115
Georgia Tech
3.
Draucker, Laura Christine.
Novel Solvent Systems for the Development of Sustainable Technology.
Degree: PhD, Chemical Engineering, 2007, Georgia Tech
URL: http://hdl.handle.net/1853/16188
► Sustainable development in chemical engineering offers technical, industrially relevant solutions to environmental and economic issues. This work focuses on three specific issues; improving solvent selection…
(more)
▼ Sustainable development in chemical engineering offers technical, industrially relevant solutions to environmental and economic issues. This work focuses on three specific issues; improving solvent selection and reducing costly experimentation, improving catalyst recovery while reducing reaction time, and producing commercial viable biofuels by cost effective pretreatments and valuable side product extractions.
Novel solvent systems are a sustainable solution because they provide the ability to replace costly solvents with cheap, benign, and recyclable systems. Specifically, this work investigated the use of one novel solvent system, Gas Expanded Liquids (GXL).When a solvent is exposed to a gas in which it is miscible at modest pressures and temperatures, the liquid solvent becomes expanded, providing a unique tunable and reversible solvent with properties that can be much different then that of the solvent itself. If you apply this gas to a mixture of two liquids of a solid dissolved in a liquid phase, it can often provide a miscibility switch, aiding in separation, crystallization, and
recovery of products or catalysts. In this work several different applications for organic
solvents expanded with carbon dioxide were studied including miscibility switches for
catalyst recycle, pretreatment of biomass for improved bio-ethanol production, and
extraction of valuable chemicals from lignin waste in the pulp and paper industry. Solid
solubility models to improve solvent selection and predict unique solvent mixtures during
crystallization were also studied. The results reported here show promise for the use of
GXL novel solvent systems and solid solubility models in many sustainable applications.
Advisors/Committee Members: Dr. Charles A. Eckert (Committee Chair), Dr. Charles L. Liotta (Committee Co-Chair), Dr. Amyn S. Teja (Committee Member), Dr. Arthur J. Ragauskas (Committee Member), Dr. Wm. James Fredrick, Jr. (Committee Member).
Subjects/Keywords: Thermodynamics; Phase behavior; Biorefineries
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APA ·
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APA (6th Edition):
Draucker, L. C. (2007). Novel Solvent Systems for the Development of Sustainable Technology. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/16188
Chicago Manual of Style (16th Edition):
Draucker, Laura Christine. “Novel Solvent Systems for the Development of Sustainable Technology.” 2007. Doctoral Dissertation, Georgia Tech. Accessed January 20, 2021.
http://hdl.handle.net/1853/16188.
MLA Handbook (7th Edition):
Draucker, Laura Christine. “Novel Solvent Systems for the Development of Sustainable Technology.” 2007. Web. 20 Jan 2021.
Vancouver:
Draucker LC. Novel Solvent Systems for the Development of Sustainable Technology. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/1853/16188.
Council of Science Editors:
Draucker LC. Novel Solvent Systems for the Development of Sustainable Technology. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/16188
Georgia Tech
4.
Myneni, Satyanarayana.
Post Plasma Etch Residue Removal Using Carbon Dioxide Based Fluids.
Degree: PhD, Chemical Engineering, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/7605
► As feature sizes in semiconductor devices become smaller and newer materials are incorporated, current methods for photoresist and post plasma etch residue removal face several…
(more)
▼ As feature sizes in semiconductor devices become smaller and newer materials are incorporated, current methods for photoresist and post plasma etch residue removal face several challenges. A cleaning process should be environmentally benign, compatible with dielectric materials and copper, and provide residue removal from narrow and high aspect ratio features. In this work, sub-critical CO2 based mixtures have been developed to remove the etch residues; these mixtures satisfy the above requirements and can potentially replace the two step residue removal process currently used in the integrated circuit (IC) industry.
Based on the chemical nature of the residue being removed, additives or co-solvents to CO2 have been identified that can remove the residues without damaging the dielectric layers. Using the phase behavior of these additives as a guide, the composition of the co-solvent was altered to achieve a single liquid phase at moderate pressures without compromising cleaning ability. The extent of residue removal has been analyzed primarily by x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Various techniques such as attenuated total reflection - Fourier transform infrared (ATR-FTIR) spectroscopy, angle-resolved XPS (ARXPS), and interferometry were used to probe the interaction of cleaning fluids with residues. Model films of photoresists and plasma deposited residues were used to assist in understanding the mechanism of residue removal. From these studies, it was concluded that residue removal takes place primarily by attack of the interface between the residue and the substrate; a solvent rinse then lifts these residues from the wafer. It has been shown that transport of the additives to the interface is enhanced in the presence of CO2. From positronium annihilation lifetime spectroscopy (PALS) studies on a porous dielectric film, it has been shown that these high pressure fluids do not cause significant changes to the pore sizes or the bonding structure of the film. Hence, this method can be used to remove post etch residues from low-k dielectric films.
Advisors/Committee Members: Dr. Dennis W. Hess (Committee Chair), Dr. Amyn S. Teja (Committee Member), Dr. Charles A. Eckert (Committee Member), Dr. Charles L. Liotta (Committee Member), Dr. J. Carson Meredith (Committee Member).
Subjects/Keywords: Low-K; Angle resolved XPS; Surface cleaning; Supercritical carbon dioxide; ATR-FTIR; Fluorocarbon residue; Etch residue; Semiconductors Cleaning; Plasma etching; Liquid carbon dioxide Industrial applications
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APA ·
Chicago ·
MLA ·
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CSE |
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to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Myneni, S. (2004). Post Plasma Etch Residue Removal Using Carbon Dioxide Based Fluids. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/7605
Chicago Manual of Style (16th Edition):
Myneni, Satyanarayana. “Post Plasma Etch Residue Removal Using Carbon Dioxide Based Fluids.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 20, 2021.
http://hdl.handle.net/1853/7605.
MLA Handbook (7th Edition):
Myneni, Satyanarayana. “Post Plasma Etch Residue Removal Using Carbon Dioxide Based Fluids.” 2004. Web. 20 Jan 2021.
Vancouver:
Myneni S. Post Plasma Etch Residue Removal Using Carbon Dioxide Based Fluids. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/1853/7605.
Council of Science Editors:
Myneni S. Post Plasma Etch Residue Removal Using Carbon Dioxide Based Fluids. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/7605
. 
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