Journal Article

IMPULSE-2019-00148

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png The role of MOFs in Thin-Film Nanocomposite (TFN) membranes

Van Goethem, C. (Corresponding author) ; Verbeke, R. ; Pfanmöller, M. ; Koschine, T. ; Dickmann, M.MLZ* ; Timpel-Lindner, T. ; Egger, W.MLZ* ; Bals, S. ; Vankelecom, I. F. J.

2018
Elsevier New York, NY [u.a.]

Please use a persistent id in citations: doi:10.1016/j.memsci.2018.06.040

Abstract: Incorporation of MOFs in interfacially polymerized Thin-Film Nanocomposite (TFN) membranes has widely been shown to result in increased membrane performance. However, the exact functioning of these membranes is poorly understood as large variability in permeance increase, filler incorporation and rejection changes can be observed in literature. The synthesis and functioning of TFN membranes (herein exemplified by ZIF-8 filled polyamide (PA) membranes prepared via the EFP method) was investigated via targeted membrane synthesis and thorough characterization via STEM-EDX, XRD and PALS. It is hypothesized that the acid generated during the interfacial polymerization (IP) at least partially degrades the crystalline, acid-sensitive ZIF-8 and that this influences the membrane formation (through so-called secondary effects, i.e. not strictly linked to the pore morphology of the MOF). Nanoscale HAADF-STEM imaging and STEM-EDX Zn-mapping revealed no ZIF-8 particles but rather the presence of randomly shaped regions with elevated Zn-content. Also XRD failed to show the presence of crystalline areas in the composite PA films. As the addition of the acid-quenching TEA led to an increase in the diffraction signal observed in XRD, the role of the acid was confirmed. The separate addition of dissolved Zn2+ to the synthesis of regular TFC membranes showed an increase in permeance while losing some salt retention, similar to observations regularly made for TFN membranes. While the addition of a porous material to a TFC membrane is a straightforward concept, all obtained results indicate that the synthesis and performance of such composite membranes is often more complex than commonly accepted.

Keyword(s): Health and Life (1st) ; Condensed Matter Physics (2nd)

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Contributing Institute(s):

1. NEPOMUC

Experiment(s):

1. NEPOMUC: Neutron induced positron source munich (SR11)

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Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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