Carbon nanotubes integrated into polyamide membranes by support pre-infiltration improve the desalination performance

Aysa Güvensoy-Morkoyun, Süer Kürklü-Kocaoğlu, Cansu Yıldırım, Sadiye Velioğlu, H. Enis Karahan, Tae Hyun Bae, Birgül Tantekin-Ersolmaz*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

Carbon nanotubes (CNTs) are promising for realizing ultrafast membranes with implications to molecular separations and beyond. However, it is a big challenge to harness the potential of CNTs for designing scalable yet high-performance membranes. Here we systematically explore the role of loading and vacuum-assisted alignment of CNTs for improving the desalination performance of polyamide (PA) based thin-film composites. To rule out the dispersion instability issues, we focused on carboxylated single-walled CNTs (SWCNTs) commercially available in the market. After applying a pre-treatment for cleaning, we deposited SWCNTs on porous polysulfone supports by vacuum filtration and coated a PA layer on top via interfacial polymerization. Morphological assessments supported by polarized Raman microspectroscopy allowed the quantification of SWCNT alignment. At an optimum SWCNT loading, which we found critical for alignment, the water permeability of resulting membranes significantly improved without compromising NaCl selectivity. Also, we achieved an improved boric acid selectivity, arguably owing to the hydrophobic nature of nanotube channels. Moreover, nanotubes promoted resistance against chlorine degradation and improved mechanical strength. Vacuum deposition is instrumental for infiltrating SWCNTs into the support layer, but a mat layer forms between the support and PA layers when SWCNT loading exceeds the limit that the support pores can accommodate. Given that we use ordinary SWCNTs and a scalable methodology (vacuum-assisted infiltration), the developed membranes are promising for practical applications.

Original languageEnglish
Pages (from-to)546-557
Number of pages12
JournalCarbon
Volume185
DOIs
Publication statusPublished - 15 Nov 2021

Bibliographical note

Publisher Copyright:
© 2021 Elsevier Ltd

Funding

This work was supported by the Scientific and Technological Research Council of Turkey (TÜBİTAK) through Grant No: 114Y165 . We acknowledge Prof. Dr. Ahmet Sirkecioğlu and Prof. Dr. Melek Tüter at ITU Chemical Engineering Department for providing access to centrifuge and UV–vis spectrometer used, respectively. We thank Dr. M. Barış Yağcı for the help with the Raman Microspectroscopy measurements. We are also grateful to Uğurcan Morkoyun for his help with the graphical representations and performance tests.

FundersFunder number
TÜBİTAK
Türkiye Bilimsel ve Teknolojik Araştirma Kurumu114Y165

    Keywords

    • Boron removal
    • Desalination
    • Interfacial polymerization
    • Reverse osmosis
    • Single-walled carbon nanotubes
    • Thin film nanocomposite

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