Abstract
Outstanding water/ion selectivity of aquaporins paves the way for bioinspired desalination membranes. Since the amino acid asparagine (Asn) plays a critical role in the fast water conduction of aquaporins through hydrogen bonding interactions, we adapted this feature by functionalizing carbon nanotubes (CNTs) with Asn. We also studied a nonpolar amino acid and carboxylate functional groups for comparison. Computation of the ideal performance of individual CNTs at atomistic scale is a powerful tool for probing the effect of tip-functionalized CNTs on water and ion transport mechanism. Molecular simulation study suggests that steric effects required for ion rejection compromise fast water conductivity; however, an Asn functional group having polarity and hydrogen bonding capability can be used to balance this trade-off to some extent. To test our hypothesis, we incorporated functionalized CNTs (f-CNTs) into the in situ polymerized selective polyamide (PA) layer of thin film nanocomposite membranes and compared their experimental RO desalination performance. The f-CNTs were found to change the separation environment through modification of cross-linking density, thickness, and hydrophilicity of the PA layer. Asn functionalization led to more cross-linked and thinner PA layer while hydrophilicity is improved compared to other functional groups. Accordingly, water permeance is increased by 25% relative to neat PA with a salt rejection above 98%. Starting from the nanomaterial itself and benefiting from molecular simulation, it is possible to design superior membranes suited for practical applications.
Original language | English |
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Pages (from-to) | 28174-28185 |
Number of pages | 12 |
Journal | ACS applied materials & interfaces |
Volume | 14 |
Issue number | 24 |
DOIs | |
Publication status | Published - 22 Jun 2022 |
Bibliographical note
Publisher Copyright:© 2022 American Chemical Society. All rights reserved.
Funding
The molecular simulations are performed at TUBITAK ULAKBIM High Performance and Grid Computing Center (TRUBA). Financial support by the Scientific and Technological Research Council of Turkey (TUBITAK, Grant No. 114Y165) and ITU Scientific Research Projects (Grant No. 40761) are acknowledged. We thank Süer Kürklü and Cansu Yıldırım for their help with the membrane characterization and Uğurcan Morkoyun for his contribution to the visual contents. We are also grateful to Dr. H. Enis Karahan for insightful discussions.
Funders | Funder number |
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International Technological University | 40761 |
Türkiye Bilimsel ve Teknolojik Araştırma Kurumu | 114Y165 |
Keywords
- biomimetic membrane
- carbon nanotube
- desalination
- molecular dynamics
- thin film nanocomposite