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Tuning Carbon Molecular Sieve Membrane Performance for Challenging Gas Separations

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Tuning Carbon Molecular Sieve Membrane Performance for Challenging Gas Separations TUNING CARBON MOLECULAR SIEVE MEMBRANE PERFORMANCE FOR CHALLENGING GAS SEPARATIONS A Dissertation Presented to The Academic Faculty by Graham B. Wenz In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in Chemical Engineering Georgia Institute of Technology May 2017 COPYRIGHT © 2017 BY GRAHAM B. WENZ TUNING CARBON MOLECULAR SIEVE MEMBRANE PERFORMANCE FOR CHALLENGING GAS SEPARATIONS Approved by: Dr. William J. Koros, Advisor Dr. Ryan P. Lively School of Chemical and Biomolecular School of Chemical and Biomolecular Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Peter J. Ludovice Dr. Pradeep K. Agrawal School of Chemical and Biomolecular School of Chemical and Biomolecular Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Meisha L. Shofner School of Material Science and Engineering Georgia Institute of Technology Date Approved: April 3rd, 2017 This work is dedicated to my parents. ACKNOWLEDGEMENTS This has been a journey with many ups and downs, and would not have been possible without the support of many people. First and foremost, I have to express my sincere gratitude to my advisor, Dr. William J. Koros. I am almost certain that I will never meet another human being more dedicated to their work. His combination of endless energy (coffee probably helps here), depth of knowledge and desire to “push the boundaries” has been, and will continue to be, inspirational. I can certainly say that without his guidance and support, I would not have made it to this point. I would also like to thank my Ph.D. committee members: Dr. Pradeep K. Agrawal, Dr. Ryan P. Lively, Dr. Pete J. Ludovice, and Dr. Meisha L. Shofner for valuable input and guidance through the important steps of my Ph.D. education. Throughout my time in the Koros group, I have had the great fortune to learn, collaborate and socialize with some amazing researchers and people. I would first like to thank all of the previous Koros group members for setting up the “kingdom” that I have utilized over the past 5 years, particularly JR Johnson and Oguz Karvan; while I did not overlap with either of you for an appreciable amount of time, I benefitted greatly from your engineering design and foresight. Justin Vaughn and Vinod Babu had the joy of sharing an office with me and both made for helpful discussions about research, but more importantly about cooking, ornithology, and activities in Atlanta. Steven Burgess shared valuable time with me, both in lab and at Dunkin’ Donuts - providing much needed breaks. Yu-Han Chu and Shilu Fu were always there for great conversations, to remind me that I should eat less, and put up with entirely too many pranks from me. Towards the iv end Chen Zhang and Gongping Liu were important colleagues and friends, serving as much needed sounding boards for a variety of subjects. Special thanks to Manjeshwar Kamath for providing tasty Indian treats on Thursdays. To the rest of the Koros group (past and present): thank you for your input and guidance throughout my time here! Outside of Bunger-Henry I have had an amazing group of friends that were an integral part of my time here, providing me with many laughs and good times. Andrew Tadros, Joanna Tsao, Dalar Nazarian, Chris Boyd, Kevin Ling, Weipeng Zhou, Michael Dutzer, Jared Schwartz and Sylvia Sullivan are just of the few were always available for shenanigans. Miles Sakwa-Novak was a go-to for sports talk, grilling and in-depth discussions of things we take for granted (e.g. why are there two tides in a day?). Last but not least, Steph Didas has been the most important source of support, companionship, and guidance throughout this process. I can say, without a shred of doubt, this would have been a much darker experience without her. I would also like to thank my parents, Marilyn Larsen and Jeff Wenz, for the continual support throughout my life, particularly during this step. While each one of my life decisions to this time has moved me further away from “home”, they never blinked in helping me see things through. They both know my struggles all too well and were always available to listen and provide words of wisdom, but more importantly, to revel alongside me in my successes. For that I will be forever grateful. There are so many more people to thank, but in the interest of time I’ll summarize with this: thank you all for everything, and if you have read this I’ll buy you a beer (or two) the next time I see you. v TABLE OF CONTENTS ACKNOWLEDGEMENTS…………………………………………………………….iv LIST OF TABLES………………………………………………………………………xi LIST OF FIGURES……………………………………………………………………xiii SUMMARY……………………………………………………………………………..xx CHAPTER 1. INTRODUCTION …………………………………………………….1 1.1 Energy Production: Advancements and Implications ………………………...1 1.2 Membrane-based Gas Separations ……………………………………………..5 1.2.1 Flexible Polymeric Membranes ………………………………………………..8 1.2.2 Polymers of Intrinsic Microporosity …………………………………………...9 1.2.3 Crystalline Molecular Sieves: Metal Organic Frameworks (MOFs) and Zeolites …………………………………………………………………………………10 1.2.4 Hybrid Materials ………………………………………………………………11 1.2.5 Amorphous Molecular Sieves: Carbon Molecular Sieves …………………….12 1.3 Research Objectives …………………………………………………………….13 1.4 Dissertation Organization ……………………………………………………...16 1.5 References ……………………………………………………………………….17 CHAPTER 2. THEORY AND BACKGROUND ………………………………….21 2.1 Overview ………………………………………………………………………...21 2.2 Structure of Carbon Molecular Sieve Membranes …………………………..21 2.3 Fundamentals of Gas Transport ………………………………………………23 2.3.1 Sorption ……………………………………………………………………….28 2.3.2 Diffusion ………………………………………………………………………29 2.3.3 Temperature Effects of Transport Processes …………………………………33 2.3.4 Diffusional Selectivity of CMS Materials: Entropic and Energetic Contributions …………………………………………………………………………34 vi 2.4 Factors Controlling Carbon Molecular Sieve Structure and Performance.. ……..37 2.4.1 Polymeric Precursor…………………………………………………………. ..37 2.4.2 Precursor Pretreatment………………………………………………………...40 2.4.3 The Pyrolysis Process…………………………………………………………42 2.4.4 Carbon Molecular Sieve Membrane Post-treatment……………………….….50 2.5 Physical Aging of Carbon Molecular Sieve Membranes………………………...52 2.6 Formation of Asymmetric Hollow Fibers: Dry-Jet/Wet-Quench Spinning……...54 2.7 References ……………………………………………………………………….59 CHAPTER 3. MATERIALS AND EXPERIMENTAL METHODS …………….64 3.1 Overview ………………………………………………………………………...64 3.2 Materials ………………………………………………………………………...64 3.2.1 Polymeric Precursors …………………………………………………………64 3.3 Membrane Formation ………………………………………………………….65 3.3.1 Polymeric Membranes ………………………………………………………...65 3.3.2 Carbon Molecular Sieve Membrane Formation ………………………………68 3.3.3 Post-synthetic Amine Doping Treatment of Asymmetric Hollow Fiber CMS Membranes…………………………………………………………………………….71 3.4 Membrane Characterization …………………………………………………...73 3.4.1 Gases …………………………………………………………………………..73 3.4.2 Permeation …………………………………………………………………….73 3.4.3 Sorption ……………………………………………………………………….77 3.4.4 Complementary Characterization Techniques ………………………………..78 3.5 References ……………………………………………………………………….80 CHAPTER 4. AMINE DOPING OF CARBON MOLECULAR SIEVE MEMBRANES …………………………………………………………………………82 4.1 Overview ………………………………………………………………………...82 4.2 Physical Aging of Carbon Molecular Sieve Hollow Fiber Membranes ……..83 4.3 Amine Doping of Carbon Molecular Sieve Membranes ……………………..86 4.3.1 Permeation Results of Amine Doped Carbon Molecular Sieve Hollow Fiber Membranes ……………………………………………………………………………90 vii 4.3.2 CO2 and CH4 Gas Sorption within Amine Doped Carbon Molecular Sieve Hollow Fiber Membranes ……………………………………………………………..95 4.4 Amine Doping as a New Modification Technique for Carbon Molecular Sieve Membranes …………………………………………………………………………...99 4.5 TGA-IR Analysis of Amine Doped Carbon Molecular Sieve Hollow Fiber Membranes ………………………………………………………………………....103 4.6 Summary and Conclusions …………………………………………………...105 4.7 References ……………………………………………………………………...106 CHAPTER 5. ROLE OF SEIZE AND FUNCTIONALITY OF AMINE DOPANTS FOR MODIFICATION OF CARBON MOLECULAR SIEVE STRUCTURE …………………………………………………………………………108 5.1 Overview ……………………………………………………………………….108 5.2 Dopant Selection: Structure and Reactivity …………………………………110 5.3 Permeation Results of Amine Doped Carbon Molecular Sieve Membranes for the CO2/CH4 Separation ……………………………………………………….113 5.4 Impacts of Amine Dopants on CO2 and CH4 Gas Sorption within Carbon Molecular Sieve Membranes ………………………………………………………115 5.5 Stability of Amine Doped Carbon Molecular Sieve Membranes …………..120 5.6 Impacts of Amine Dopant Structure on C3H6/C3H8 Separation Performance …………………………………………………………………………………..125 5.7 Comparison between Reactive and Non-reactive Dopant Molecules ………128 5.8 NMR Analysis to Determine Chemical Functionality of Amine Dopants in Carbon Molecular Sieve Membranes …………………………………………….132 5.8.1 15N-PPDA Treated Carbon Molecular Sieve Membranes …………………..133 5.8.2 15N-Aniline Treated Carbon Molecular Sieve Membranes ………………....135 5.9 Summary and Conclusions …………………………………………………...137 5.10 References ……………………………………………………………………...139 CHAPTER 6. CARBON MOLECULAR SIEVE STRUCTURE AND MEMBRANE PERFORMANCE RELATIONSHIPS ……………………………..141 6.1 Overview ……………………………………………………………………….141 viii 6.2 Current Carbon Molecular Sieve Structure and Characterization Limits………142 6.3 Evolution of the Carbon Molecular Sieve Structure ………………………..144 6.4 Impacts of Precursor Structure ………………………………………………152 6.4.1 Sorption Isotherms and Pore Distribution Analysis from CO2 Sorption
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