Journal Article

IMPULSE-2026-00097

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Neutron transmission studies with GdCl$_{3}$ for tracing concentration polarization in reverse osmosis

Pipich, V.MLZ* ; Starc, T. ; Petry, W.MLZ* ; Oren, Y. ; Schwahn, D.

2026
Elsevier New York, NY [u.a.]

Please use a persistent id in citations: doi:10.1016/j.memsci.2025.124884

Abstract: Concentration polarization (CP) is determined by neutron transmission in a reverse osmosis (RO) system consisting of two cells, one with and the other without an RO membrane, to get the net neutron response for the feed solution in front and far from the membrane separately. The aqueous feed was a dilute solution of NaCl and GdCl3. The special feature of these experiments is that GdCl3 can be selectively determined with neutrons, since the neutron absorption cross-section of Gd is larger orders of magnitude compared to other elements such as Na, Cl, and water, and therefore has a strong influence on the overall transparency of the sample for neutrons. It is therefore the transmission of neutrons through both cells (one with and the other without membrane), by which the concentration and CP of GdCl3 can be determined. Transmission and small-angle scattering (SANS) were measured in parallel, demonstrating the performance of this method as an in-situ method for determining CP as a function of time under near-realistic conditions. The neutron experiments are complemented by measurements of permeate flux and electrical conductivity of the feed, which were used to determine the salt concentrations, the osmotic pressure and the concentration polarization of the two salts individually and of a mixture of both. The CP results of this study are in good agreement with the values presented in the literature, determined mainly from flux data under a wide variety of conditions.

Keyword(s): Instrument and Method Development (1st) ; Instrument and Method Development (2nd) ; Soft Condensed Matter (2nd)

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Contributing Institute(s):

1. Heinz Maier-Leibnitz Zentrum (MLZ)
2. JCNS-FRM-II (JCNS-FRM-II)
3. KWS3 (KWS3)

Experiment(s):

1. KWS-1: Small angle scattering diffractometer (NL3b)
2. KWS-3: Very small angle scattering diffractometer with focusing mirror (NL3auS)

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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 ; Essential Science Indicators ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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