Overcoming the Trade-Off between Methanol Rejection and Proton Conductivity via Facile Synthesis of Crosslinked Sulfonated PEEK Proton Exchange Membranes
In this work, homogeneous, thin-film proton exchange membranes (PEMs) with superior proton conductivities and high methanol rejection were fabricated via a facile synthesis procedure. Sulfonated polyether ether ketone (sPEEK) was crosslinked via a Friedel–Crafts reaction by α,α′-dichloro-p-xylene, a...
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MDPI AG
2024-04-01
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| author | Stef Depuydt Lucy Traub Gilles Van Eygen Santosh Kumar Georg Held Bart Van der Bruggen |
| author_facet | Stef Depuydt Lucy Traub Gilles Van Eygen Santosh Kumar Georg Held Bart Van der Bruggen |
| author_sort | Stef Depuydt |
| collection | DOAJ |
| description | In this work, homogeneous, thin-film proton exchange membranes (PEMs) with superior proton conductivities and high methanol rejection were fabricated via a facile synthesis procedure. Sulfonated polyether ether ketone (sPEEK) was crosslinked via a Friedel–Crafts reaction by α,α′-dichloro-p-xylene, a non-hazardous and hydrophobic compound. PEMs with varying crosslinking and sulfonation degrees were fabricated to overcome the traditional trade-off between methanol rejection and proton conductivity. The sulfonation of PEEK at 60 °C for 24 h resulted in a sulfonation degree of 56%. Those highly sulfonated backbones, in combination with a low membrane thickness (ca. 20 µm), resulted in proton conductivities superior to Nafion 117. Furthermore, X-ray photoelectron spectroscopy proved it was possible to control the crosslinking degree via the crosslinking time and temperature. The PEMs with the highest crosslinking degree showed better methanol rejection compared to the commercial benchmark. The introduction of the crosslinker created hydrophobic membrane sections, which reduced the water and methanol uptake. Subsequently, the membrane became denser due to the crosslinking, hindering the solute permeation. Those two effects led to lower methanol crossovers. This study proved the successful fabrication of PEMs overcoming the trade-off between proton conductivity and methanol rejection, following a facile procedure using low-cost and non-hazardous materials. |
| first_indexed | 2024-04-24T10:49:26Z |
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| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-04-24T10:49:26Z |
| publishDate | 2024-04-01 |
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| series | Applied Sciences |
| spelling | doaj.art-ebba3c5d5ff044b4820458e2edc6abe42024-04-12T13:15:40ZengMDPI AGApplied Sciences2076-34172024-04-01147308910.3390/app14073089Overcoming the Trade-Off between Methanol Rejection and Proton Conductivity via Facile Synthesis of Crosslinked Sulfonated PEEK Proton Exchange MembranesStef Depuydt0Lucy Traub1Gilles Van Eygen2Santosh Kumar3Georg Held4Bart Van der Bruggen5Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, BelgiumDepartment of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USADepartment of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, BelgiumDiamond Light Source Ltd., Harwell Science and Innovation Campus, Fermi Ave, Didcot OX11 0DE, UKDiamond Light Source Ltd., Harwell Science and Innovation Campus, Fermi Ave, Didcot OX11 0DE, UKDepartment of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, BelgiumIn this work, homogeneous, thin-film proton exchange membranes (PEMs) with superior proton conductivities and high methanol rejection were fabricated via a facile synthesis procedure. Sulfonated polyether ether ketone (sPEEK) was crosslinked via a Friedel–Crafts reaction by α,α′-dichloro-p-xylene, a non-hazardous and hydrophobic compound. PEMs with varying crosslinking and sulfonation degrees were fabricated to overcome the traditional trade-off between methanol rejection and proton conductivity. The sulfonation of PEEK at 60 °C for 24 h resulted in a sulfonation degree of 56%. Those highly sulfonated backbones, in combination with a low membrane thickness (ca. 20 µm), resulted in proton conductivities superior to Nafion 117. Furthermore, X-ray photoelectron spectroscopy proved it was possible to control the crosslinking degree via the crosslinking time and temperature. The PEMs with the highest crosslinking degree showed better methanol rejection compared to the commercial benchmark. The introduction of the crosslinker created hydrophobic membrane sections, which reduced the water and methanol uptake. Subsequently, the membrane became denser due to the crosslinking, hindering the solute permeation. Those two effects led to lower methanol crossovers. This study proved the successful fabrication of PEMs overcoming the trade-off between proton conductivity and methanol rejection, following a facile procedure using low-cost and non-hazardous materials.https://www.mdpi.com/2076-3417/14/7/3089electrochemistrymembrane synthesiscation exchange membraneproton conductivitypolyether ether ketonemethanol retention |
| spellingShingle | Stef Depuydt Lucy Traub Gilles Van Eygen Santosh Kumar Georg Held Bart Van der Bruggen Overcoming the Trade-Off between Methanol Rejection and Proton Conductivity via Facile Synthesis of Crosslinked Sulfonated PEEK Proton Exchange Membranes Applied Sciences electrochemistry membrane synthesis cation exchange membrane proton conductivity polyether ether ketone methanol retention |
| title | Overcoming the Trade-Off between Methanol Rejection and Proton Conductivity via Facile Synthesis of Crosslinked Sulfonated PEEK Proton Exchange Membranes |
| title_full | Overcoming the Trade-Off between Methanol Rejection and Proton Conductivity via Facile Synthesis of Crosslinked Sulfonated PEEK Proton Exchange Membranes |
| title_fullStr | Overcoming the Trade-Off between Methanol Rejection and Proton Conductivity via Facile Synthesis of Crosslinked Sulfonated PEEK Proton Exchange Membranes |
| title_full_unstemmed | Overcoming the Trade-Off between Methanol Rejection and Proton Conductivity via Facile Synthesis of Crosslinked Sulfonated PEEK Proton Exchange Membranes |
| title_short | Overcoming the Trade-Off between Methanol Rejection and Proton Conductivity via Facile Synthesis of Crosslinked Sulfonated PEEK Proton Exchange Membranes |
| title_sort | overcoming the trade off between methanol rejection and proton conductivity via facile synthesis of crosslinked sulfonated peek proton exchange membranes |
| topic | electrochemistry membrane synthesis cation exchange membrane proton conductivity polyether ether ketone methanol retention |
| url | https://www.mdpi.com/2076-3417/14/7/3089 |
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