TY - JOUR
T1 - Effects of Feed Solution pH on Polyelectrolyte Multilayer Nanofiltration Membranes
AU - Junker, Moritz A.
AU - Regenspurg, Jurjen A.
AU - Valdes Rivera, Cristobal I.
AU - Brinke, Esra te
AU - de Vos, Wiebe M.
N1 - Funding Information:
Funding was received from the research programme Innovatiefonds Chemie (LIFT). Project number 731.016.404, financed by The Netherlands Organisation for Scientific Research (NWO), NX Filtration (Enschede, The Netherlands), and Oasen (Gouda, The Netherlands). This work was also supported by the European Union Horizon 2020 research and innovation program (ERC StG 714744 SAMBA). Furthermore, this project was made possible through financial support of Oasen (Gouda, Netherlands), NX Filtration (Enschede, Netherlands), and the TKI HTSM, Netherlands, through the University of Twente connecting industry program.
Publisher Copyright:
© 2022 The Authors. Published by American Chemical Society.
PY - 2023/1/13
Y1 - 2023/1/13
N2 - Over the past decade polyelectrolyte multilayer (PEM)-based membranes have gained a lot of interest in the field of nanofiltration (NF) as an alternative to conventional polyamide-based thin film composite membranes. With great variety in fabrication conditions, these membranes can achieve superior properties such as high chemical resistance and excellent filtration performance. Some of the most common polyelectrolytes used to prepare NF membranes are weak, meaning that their charge density depends on pH within the normal window of operation relevant for potential applications (pH 0-14). This might cause a dependency of membrane properties on the pH of filtered solutions, as indicated by other applications of PEMs. In this work, the susceptibility of membrane structure (swelling and surface charge) and performance (permeability, molecular weight cutoff, and salt retention) toward the pH of the filtration solution was studied for four fundamentally different PEM systems: poly(diallyldimethylammonium chloride) (PDADMAC)/poly(sodium-4-styrenesulfonate) (PSS) (strong/strong), poly(allylamine hydrochloric acid) (PAH)/poly(acrylic acid) (PAA) (weak/weak), and PAH/PSS (weak/strong) and PAH/PSS+PAH/PAA (asymmetric). Slight variations in structure and performance of the PDADMAC/PSS-based membranes were observed. On the contrary, structure and performance of PAH/PAA-based membranes are very susceptible to feed solution pH. A continuous change in charge density with variation in pH significantly affects salt retention. An increased swelling at pH 9 translates to variation in permeability and molecular weight cutoff of the membrane. The susceptibility of PAH/PSS-based membranes to pH is less pronounced compared to the PAH/PAA-based membranes since only one of the polyelectrolytes involved is weak. No structural changes were observed, indicating additional specific interactions between the polyelectrolytes other than electrostatic forces that stabilize film structure. A combination of the PAH/PSS and PAH/PAA system (8 + 2 bilayers) also displays a clear dependency of both membrane structure and performance on solution pH, where PAH/PSS is dominating due to a higher bilayer number.
AB - Over the past decade polyelectrolyte multilayer (PEM)-based membranes have gained a lot of interest in the field of nanofiltration (NF) as an alternative to conventional polyamide-based thin film composite membranes. With great variety in fabrication conditions, these membranes can achieve superior properties such as high chemical resistance and excellent filtration performance. Some of the most common polyelectrolytes used to prepare NF membranes are weak, meaning that their charge density depends on pH within the normal window of operation relevant for potential applications (pH 0-14). This might cause a dependency of membrane properties on the pH of filtered solutions, as indicated by other applications of PEMs. In this work, the susceptibility of membrane structure (swelling and surface charge) and performance (permeability, molecular weight cutoff, and salt retention) toward the pH of the filtration solution was studied for four fundamentally different PEM systems: poly(diallyldimethylammonium chloride) (PDADMAC)/poly(sodium-4-styrenesulfonate) (PSS) (strong/strong), poly(allylamine hydrochloric acid) (PAH)/poly(acrylic acid) (PAA) (weak/weak), and PAH/PSS (weak/strong) and PAH/PSS+PAH/PAA (asymmetric). Slight variations in structure and performance of the PDADMAC/PSS-based membranes were observed. On the contrary, structure and performance of PAH/PAA-based membranes are very susceptible to feed solution pH. A continuous change in charge density with variation in pH significantly affects salt retention. An increased swelling at pH 9 translates to variation in permeability and molecular weight cutoff of the membrane. The susceptibility of PAH/PSS-based membranes to pH is less pronounced compared to the PAH/PAA-based membranes since only one of the polyelectrolytes involved is weak. No structural changes were observed, indicating additional specific interactions between the polyelectrolytes other than electrostatic forces that stabilize film structure. A combination of the PAH/PSS and PAH/PAA system (8 + 2 bilayers) also displays a clear dependency of both membrane structure and performance on solution pH, where PAH/PSS is dominating due to a higher bilayer number.
KW - Hollow fiber
KW - Membranes
KW - Nanofiltration
KW - pH sensitivity
KW - Polyelectrolyte multilayers
KW - UT-Hybrid-D
UR - http://www.scopus.com/inward/record.url?scp=85144760602&partnerID=8YFLogxK
U2 - 10.1021/acsapm.2c01542
DO - 10.1021/acsapm.2c01542
M3 - Article
AN - SCOPUS:85144760602
VL - 5
SP - 355
EP - 369
JO - ACS Applied Polymer Materials
JF - ACS Applied Polymer Materials
SN - 2637-6105
IS - 1
ER -