Synthesis and Permeation of Large Pore Metal-organic Framework Membranes by Alexandra ...

237 Pages·2015·3.82 MB·English

Synthesis and Permeation of Large Pore Metal-organic Framework Membranes
by
Alexandra Kasik

A Dissertation Presented in Partial Fulfillment
of the Requirements for the Degree
Doctor of Philosophy

Approved November 2015 by the
Graduate Supervisory Committee:

Jerry Lin, Chair
Amaneh Tasooji
Terry Alford

ARIZONA STATE UNIVERSITY
December 2015
ABSTRACT

Large-pore metal-organic framework (MOF) membranes offer potential in a
number of gas and liquid separations due to their wide and selective adsorption
capacities. A key characteristic of a number of MOF and zeolitic imidazolate framework
(ZIF) membranes is their highly selective adsorption capacities for CO . These
2
membranes offer very tangible potential to separate CO in a number of industrially
2
relevant separation processes, such as the separation from CO in flue gas emissions, as
2
well as the sweetening of methane.
By virtue of this, the purpose of this dissertation is to synthesize and characterize
two linear large-pore MOF membranes, MOF-5 and ZIF-68, and to study their gas
separation properties in binary mixtures of CO /N and CO /CH . The three main
2 2 2 4
objectives researched are as follows. The first is to study the pervaporation behavior and
stability of MOF-5; this is imperative because although MOF-5 exhibits desirable
adsorption and separation characteristics, it is very unstable in atmospheric conditions. In
determining its stability and behavior in pervaporation, this material can be utilized in
conditions wherein atmospheric levels of moisture can be avoided. The second objective
is to synthesize, optimize and characterize a linear, more stable MOF membrane, ZIF-68.
The final objective is to study in tandem the high-pressure gas separation behavior of
MOF-5 and ZIF-68 in binary gas systems of both CO /N and CO /CH .
2 2 2 4
Continuous ZIF-68 membranes were synthesized via the reactive seeding method
and the modified reactive seeding method. These membranes, as with the MOF-5
membranes synthesized herein, both showed adherence to Knudsen diffusion, indicating
limited defects. Organic solvent experiments indicated that MOF-5 and ZIF-68 were
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stable in a variety of organic solvents, but both showed reductions in permeation flux of
the tested molecules. These reductions were attributed to fouling and found to be
cumulative up until a saturation of available bonding sites for molecules was reached and
stable pervaporation permeances were reached for both. Gas separation behavior for
MOF-5 showed direct dependence on the CO partial pressure and the overall feed
2
pressure, while ZIF-68 did not show similar behavior. Differences in separation behavior
are attributable to orientation of the ZIF-68 membranes.

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DEDICATION

To Bob,
This degree is just as much yours as mine.
You knew I could do this even when I had moments when I wasn’t so sure myself, and
this wouldn’t have been possible without your endless love and support.
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ACKNOWLEDGMENTS

If it takes a village to raise a child, that certainly extends to doctorate degrees, as
well. I have been so blessed to have had countless advocates, cheerleaders and angels
help me on this long, strange journey. With that said, I absolutely need to thank my
family. From my mom being my biggest cheerleader through all of grad school’s ups and
downs, to my dad who taught me through his actions my entire life the importance of
hard work, integrity and goofiness. As for my brother, I am continually in awe of his
strength, physically of course, but also emotionally and mentally. And of course, Bob
and Stephanie, who certainly qualify as family at this point.
I feel so lucky to have gotten to work for Prof. Lin. His guidance and endless
patience were hugely instrumental in my attaining this degree and it was a privilege to be
guided through this PhD by someone so kind and knowledgeable and passionate about
his field of study. I also want to thank all past and present members of Prof. Lin’s group
for their continual encouragement, friendship and support. I consider all of them my
friends, and I am so excited to have been able to be a part of such an amazing research
group. Also, Fred Pena, whose help and efforts have undoubtedly aided in the graduating
of countless students. I am so thankful for every bit of encouragement, support and
insight he has given me.
I would like to thank my committee members, Prof. Amaneh Tasooji and Prof.
Terry Alford, not only for their time and efforts in their roles as committee members, but
also in the impact they had on me as an undergraduate student. It is nothing short of a
miracle that the people behind Materials Science and Engineering at ASU could take a
kid who never even wanted to go to college and was on the verge of dropping out of
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business school and support, encourage and foster such a deep love of the subject matter
that it eventually culminated in a doctorate in the subject. I had such an incredible
experience at this school, with the people, resources and structuring that I had access to,
that I know unequivocally I would not have had this success at any other institution.
Never one to leave a thank you un-thank you’d… I can’t omit some of the most
important furry, quadrupedal people in my life: Gertie, Chuck, Ursula and my dearly
departed Tonk and Pogie. Their continual supply of kisses and wiggles and tear-inducing
gas makes life worth living, and I thankful to my wiggly little buddies for their
unwavering love and silliness.
Finally, 6 years ago as I began to navigate the nebulous process of leaving full-
time work for misadventures in graduate studies, there was a constant guiding light of
support and encouragement, Yolanda Murphy. I might be one of the last graduating
students to have been lucky enough to have had her as an advisor, and I just want to
thank her for her help. She absolutely cared about her students and their success, and I
am so fortunate to have been able to know her.
Further, I would like to acknowledge the funding from the National Science
Foundation, which supported this work in its entirety.

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TABLE OF CONTENTS
Page
LIST OF TABLES ................................................................................................................... vi
LIST OF FIGURES ............................................................................................................... vii
CHAPTER
1 INTRODUCTION ........................ .................................................................................. 1
1.1 General Introduction .......................................................................................................... 1
1.1.1 Polymeric Membranes ................................................................................................ 2
1.1.2 Inorganic Membranes ................................................................................................. 6
1.1.3 Metal-organic Frameworks ........................................................................................ 9
1.2 Synthesis of MOF Membranes........................................................................................ 12
1.2.1 In Situ Synthesis ........................................................................................................ 14
1.2.2 Seeded Secondary Growth Synthesis ....................................................................... 17
1.2.3 Novel Synthesis Methods ......................................................................................... 20
1.3 Separation Processes........................................................................................................ 28
1.3.1 Membrane Separation Principles ............................................................................. 29
1.3.2 CO /H ....................................................................................................................... 35
2 2
1.3.3 CO /N ....................................................................................................................... 41
2 2
1.3.4 CO /CH .................................................................................................................... 46
2 4
1.3.5 CO /CO ..................................................................................................................... 50
2
1.4 Pervaporation ................................................................................................................... 54
1.5 Research Objectives and Significance ............................................................................ 59
1.6 Structure of the Dissertation ............................................................................................ 61
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CHAPTER Page
2 ORGANIC SOLVENT PERVAPORATION OF MOF-5 ........................................... 62
2.1 Introduction ..................................................................................................................... 62
2.2 Experimental ................................................................................................................... 64
2.2.1 Synthesis of MOF-5 Seeds and Suspension .............................................................. 64
2.2.2 MOF-5 Membrane Synthesis .................................................................................... 65
2.2.3 MOF-5 Membrane Characterization ......................................................................... 67
2.2.4 MOF-5 Pervaporation ................................................................................................ 69
2.3 Results and Discussion ................................................................................................... 71
2.4 Conclusion....................................................................................................................... 85
3 SYNTHESIS AND STABILITY OF ZEOLITIC IMIDAZOLATE FRAMEWORK-
68 MEMBRANES ....................................................................................................... 86
3.1 Introduction ..................................................................................................................... 86
3.2 Experimental ................................................................................................................... 88
3.2.1 Zinc Oxide Supports .................................................................................................. 88
3.2.2 ZIF-68 Seed Layer Synthesis .................................................................................... 89
3.2.3 ZIF-68 Secondary Growth ......................................................................................... 90
3.2.4 Characterization of ZIF-68 Crystals and Membranes .............................................. 91
3.2.5 ZIF-68 Stability Tests ................................................................................................ 92
3.3 Results and Discussion ................................................................................................... 92
3.2 Conclusions ................................................................................................................... 112

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CHAPTER Page
4 SYNTHESIS AND CHARACTERIZATION OF ZIF-68 SYNTHESIZED BY THE
IMPROVED REACTIVE SEEDING METHOD .................................................. 113
4.1 Introduction .................................................................................................................. 113
4.2 Experimental ................................................................................................................ 115
4.2.1 Alumina Supports ................................................................................................... 115
4.2.2 Surface Modification via Dip Coating and Sintering ............................................ 115
4.2.3 Surface Modification via In Situ Deposition of ZnO ............................................. 116
4.2.4 Reactive Seeding of ZIF-68 .................................................................................... 117
4.2.5 Secondary Growth of ZIF-68 Membranes ............................................................. 117
4.2.6 Characterization ...................................................................................................... 117
4.3 Results and Discussion ................................................................................................. 119
4.3.1 ZnO Coating on Al O ............................................................................................ 119
2 3
4.3.2 Seeding and Membrane Synthesis.......................................................................... 124
4.3.3 Membrane Characterization ................................................................................... 133
4.4 Conclusion..................................................................................................................... 144
5 BINARY GAS SEPARATION OF MOF-5 AND ZIF-68 ......................................... 145
5.1 Introduction ................................................................................................................... 145
5.2 Experimental ................................................................................................................. 147
5.2.1 MOF-5 Membrane Synthesis .................................................................................. 147
5.2.2 ZIF-68 Membrane Synthesis ................................................................................... 149
5.2.3 Characterization and Binary Gas Separation .......................................................... 150
5.3 Results and Discussion ................................................................................................. 152
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CHAPTER Page
5.3.1 MOF-5 Binary Gas Separation ................................................................................ 152
5.3.2 ZIF-68 Binary Gas Separation ................................................................................ 161
5.4 Conclusions ................................................................................................................... 168
6 SUGGESTIONS FOR FUTURE WORK .................................................................... 170
6.1 Summary ......................................................................................................................... 170
6.2 Recommendations ........................................................................................................... 173
6.2.1 MOF-5 Stability ....................................................................................................... 173
6.2.2 ZIF-68 C-Oriented Membranes ............................................................................... 174
REFERENCES....... ............................................................................................................ 175
APPENDIX
A PROCEDURE FOR SYNTHESIS OF HOMEMADE ALPHA ALUMINA SUPPORTS
........................................................................................................................................ 189
B PROCEDURE FOR MOF-5 MEMBRANE SYNTHESIS VIA SEEDING AND
SECONDARY GROWTH ........................................................................................... 191
C PROCEDURE FOR SYNTHESIS OF HOMEMADE ZINC OXIDE SUPPORTS ... 195
D PROCEDURE FOR ZIF-68 MEMBRANE SYNTHESIS VIA REACTIVE SEEDING
.............................. ................................................................................................................ 197
E PROCEDURE FOR THE SYNTHESIS OF ZIF-68 MEMBRANES VIA MODIFIED
REACTIVE SEEDING METHOD ............................................................................. 200
F PROCEDURE FOR THE SYNTHESIS OF ZIF-68 CRYSTALS ............................. 204
G PROCEDURE FOR TESTING SINGLE COMPONENT GAS PERMEATION ...... 207
H PROCEDURE FOR TESTING SINGLE COMPONENT PERVAPORATION ....... 210
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