(722f) Preparation of ZIF-8 Membranes Supported on Polymer Hollow Fibers Using Microwave-Assisted Seeding and Secondary Growth

Preparation of ZIF-8 Membranes
supported on Polymer Hollow Fibers using Microwave-assisted Seeding and Secondary
Growth

Moon Joo Lee¹,
Mohamad Rezi Abdul Hamid¹, Jongmyeong Lee³, Ju
Sung Kim³, Young Moo Lee³ and Hae-Kwon Jeong*^1,2

¹Artie
McFerrin Department of Chemical Engineering and ²Department of Materials
Science and Engineering, Texas A&M University, College Station, TX 77843-3122
³Department of Energy Engineering, College of Engineering, Hanyang University, Seoul 133-791, Republic of Korea

* Corresponding author: hjeong7@tamu.edu

Separation of olefin/paraffin mixtures, e.g.
propylene/propane, is one of the most
challenging separations due to the similarity of their physicochemical properties.
Currently, an energy intensive cryo-distillation process is employed. Though energy-efficient
membrane-based separation processes are drawing significant interest, no
membranes are commercially available for olefin/paraffin separations mainly due
to the limitations of current membrane materials and processing methods to
fabricate their membranes with large membrane areas.^1-3

Zeolitic-imidazolate
frameworks (ZIFs), a sub-class of metal-organic
frameworks (MOFs) with zeolite topology, are
highly crystalline nanoporous materials
with aperture sizes of typically less than 5 Å. ZIFs composed of metal ions (typically
Zn²⁺ and Co²⁺) and imidazole-derived organic linkers,⁴ have
been extensively studied for gas separation applications. Specifically, ZIF-8 is shown very promising as a new
membrane material for propylene/propane
separation because the effective pore
size is in between the size of propylene
and propane. While several ZIF-8 membranes
showed high propylene/propane separation factors, however, there are critical
issues for their commercial applications: 1) high cost of membranes and 2) low
productivities. To increase the productivity and to reduce the cost of ZIF-8
membranes, polymeric hollow fibers have been utilized
as substrates, but only a few of the
resulting ZIF-8 membranes showed promising propylene/propane separation
performances.^6-9

Herein, we would like to present a microwave-based method to prepare well inter-grown ZIF-8 membranes on
polymeric hollow fibers readily. The method is modified based on our
previously reported microwave-assisted seeding and secondary growth technique.¹⁰
Densely-packed nano-sized ZIF-8 seed crystals were rapidly prepared on either inner or outer
surface of hollow fibers under microwave heating. Subsequently, seed crystals were
secondarily grown into continuous ZIF-8 films on polyimide hollow
fibers. The thickness of the resulting ZIF-8 membranes was much smaller than
any ZIF-8 membranes grown on polymer hollow fibers reported, which are several
micrometers in thickness. The effects of synthesis parameters and fiber
morphologies on the microstructures of ZIF-8 membranes will be discussed. Finally, the gas separation
performances of ZIF-8 membranes will be
presented.

References and Notes

1
Koros, William J. and Fleming, G.K. (1993) “Membrane-based
gas separation”, Journal of Membrane Science, 83, pp l-39

2
Baker RW., (2002) “Future Directions of Membrane
Gas Separation Technology” Industrial
& Engineering Chemistry Research., 41 (6), pp 1393-1411

3
Tanaka, K., Taguchi, A., Hao, JQ, Kita, H., and Okamoto, K., (1996) “Permeation
and separation properties of polyimide membranes to olefins and paraffins”, Journal
of Membrane Science, 121, pp 197-207

4
Park KS, Ni Z, Côté AP, et al., (2006) “Exceptional
chemical and thermal stability of zeolitic imidazolate frameworks”, Proceedings of the National Academy of
Sciences, 103 (27), pp 10186-10191

5 Zhang C, Lively RP, Zhang K, Johnson JR, Karvan O, Koros
WJ., (2012) “Unexpected Molecular Sieving Properties of Zeolitic Imidazolate
Framework-8”, The Journal of Physical
Chemistry Letters., 3 (16), pp 2130-2134.

6 Andrew J. Brown, Nicholas A. Brunelli, Kiwon Eum,
Fereshteh Rashidi, J. R. Johnson, William J. Koros, Christopher W. Jones,
Sankar Nair, (2014) “Interfacial microfluidic processing of metal-organic
framework hollow fiber membranes”, Science,
345, 6192, pp 72-75

7 FernandoCacho-Bailo, SilviaCatalán-Aguirre,
MirenEtxeberría-Benavides, Oğuz Karvan, VictorSebastian, CarlosTéllez,
JoaquínCoronas (2015) “Metal-organic framework membranes on the inner-side of a
polymeric hollow fiber by microfluidic synthesis”, Journal of membrane science, 476, pp 277-285

8 Kiwon Eum, Chen Ma, Ali Rownaghi, Christopher W.
Jones, and Sankar Nair (2016) “ZIF‑8 Membranes via Interfacial Microfluidic Processing in
Polymeric Hollow Fibers: Efficient Propylene Separation at Elevated Pressures”,
ACS Applied materials and interfaces,
8, pp 25337 – 25342

9 Anne M. Marti, Wasala Wickramanayake, Ganpat Dahe,
Ali Sekizkardes, Tracy L. Bank, David P. Hopkinson, and Surendar R. Venna
(2017) “Continuous Flow Processing of ZIF‑8 Membranes on Polymeric Porous Hollow Fiber Supports
for CO2 Capture”, ACS Applied materials
and interfaces, 9, pp 5678-5682

10
Kwon HT, Jeong H-K., (2013), “Highly
propylene-selective supported zeolite-imidazolate framework
(ZIF-8) membranes synthesized by rapid microwave-assisted seeding and secondary
growth”, Chemical Communications, 49, pp 3854-3856