TY - JOUR
T1 - Influence of concentration polarization and thermodynamic non-ideality on salt transport in reverse osmosis membranes
AU - Jang, Eui-Soung
AU - Mickols, William
AU - Sujanani, Rahul
AU - Helenic, Alysha
AU - Dilenschneider, Theodore J.
AU - Kamcev, Jovan
AU - Paul, Donald R.
AU - Freeman, Benny D.
N1 - Funding Information:
This material is based upon work supported in part by the Welch Foundation Grant No. F-1924-20170325 . A.H. was supported in part by the National Science Foundation (NSF) Graduate Research Fellowship under Grant No. DGE-1610403 . Additionally, B.D.F.’s contributions to the preparation of this manuscript were supported as part of the Center for Materials for Water and Energy Systems (M-WET), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0019272 .
Publisher Copyright:
© 2018 Elsevier B.V.
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/2/15
Y1 - 2019/2/15
N2 - The classic Merten and Lonsdale transport model for reverse osmosis membranes was reformulated to explicitly demonstrate the effects of concentration polarization and solution phase thermodynamic non-idealities on salt transport. A framework presented here accounts for the concentration dependence of ion activity coefficients in salt solutions, which was not explicitly included in the classic model. This approach was applied to four salt solutions, NaCl, MgCl2, CaCl2, and Na2SO4, tested in cross-flow conditions for a commercial RO membrane, Dow Filmtec™ BW30XFR. Salt transport coefficients corrected for concentration polarization and non-ideal thermodynamic effects, Ba, were calculated as a function of permeate flux and compared with apparent salt transport coefficients, B. These corrections were significant, resulting in Ba values greater than B values by a factor of 1.3–2.1 for 2:1 and 1:2 salts (i.e., MgCl2, CaCl2, and Na2SO4). Ba values for NaCl (a 1:1 salt), however, were similar to or somewhat smaller than B values.
AB - The classic Merten and Lonsdale transport model for reverse osmosis membranes was reformulated to explicitly demonstrate the effects of concentration polarization and solution phase thermodynamic non-idealities on salt transport. A framework presented here accounts for the concentration dependence of ion activity coefficients in salt solutions, which was not explicitly included in the classic model. This approach was applied to four salt solutions, NaCl, MgCl2, CaCl2, and Na2SO4, tested in cross-flow conditions for a commercial RO membrane, Dow Filmtec™ BW30XFR. Salt transport coefficients corrected for concentration polarization and non-ideal thermodynamic effects, Ba, were calculated as a function of permeate flux and compared with apparent salt transport coefficients, B. These corrections were significant, resulting in Ba values greater than B values by a factor of 1.3–2.1 for 2:1 and 1:2 salts (i.e., MgCl2, CaCl2, and Na2SO4). Ba values for NaCl (a 1:1 salt), however, were similar to or somewhat smaller than B values.
KW - Desalination
KW - Membranes
KW - Reverse osmosis (RO)
KW - Salt transport
KW - The Merten and Lonsdale model
UR - http://www.scopus.com/inward/record.url?scp=85058166811&partnerID=8YFLogxK
U2 - 10.1016/j.memsci.2018.11.006
DO - 10.1016/j.memsci.2018.11.006
M3 - Article
AN - SCOPUS:85058166811
SN - 0376-7388
VL - 572
SP - 668
EP - 675
JO - Journal of Membrane Science
JF - Journal of Membrane Science
ER -