Optimization of the mass ratio of Siloxane crosslinkers for poly(2,6-dimethyl-1,4-phenylene oxide) anion exchange membranes to improve acid enrichment by electrodialysis

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Type
Article
Citation
Ruan, H., Gao, S., Li, Y., Yu, S., Liao, J., Ang, E. H., Xu, Y., & Shen, J. (2024). Optimization of the mass ratio of Siloxane crosslinkers for poly(2,6-dimethyl-1,4-phenylene oxide) anion exchange membranes to improve acid enrichment by electrodialysis. Journal of Membrane Science, 695, Article 122487. https://doi.org/10.1016/j.memsci.2024.122487
Author
Ruan, Huimin
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Gao, Shangshang
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Li, Yeyang
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Yu, Shuaijun
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Liao, Junbin
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Ang, Edison Huixiang 
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Xu, Yanqing
•
Shen, Jiangnan
Abstract
Proton blocking anion exchange membranes (AEMs), which are employed in electrodialysis technology, show promise in acid recovery from industrial waste. A series of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) membranes were prepared using (3-aminopropyl)trimethoxysilane (APTMS) and weakly functionalized bases including N-butylimidazole (N-BuIm). Were networked to create AEMs with low leak rates. It was discovered that the appropriate concentration of siloxane crosslinker raised the membrane matrix's density and lowered the AEM matrix's hydrophilicity. Thermogravimetric measurements and water absorption have confirmed this, and the membranes in this series even swell up to 8.61 %. The maximum H+ concentration concentrated by the cross-linked AEM (BPPO/5Si) during the ED with a current density of 10 mAcm−2 was 2.35 M, which was higher than the concentration concentrated by the uncross-linked AEM (BPPO/OSi), which was 1.90 M (beginning concentration: 1.00 M). The current efficiency was 44.8 % and the energy consumption was only 1.81 kW ∙h∙kg−1. A balance between proton blocking and SO42− ions transport was achieved by the optimized AEM, which exhibited increased hydrophobicity and smaller ion clusters. The improved AEM was found to have fewer ionic clusters and greater hydrophobicity. For cross-linked AEMs, a trade-off between SO42− ions transport and proton blocking was thus accomplished. This work is thought to offer direction for developing sophisticated proton blocking AEMs.
Date Issued
2024
Publisher
Elsevier
Journal
Journal of Membrane Science
DOI
10.1016/j.memsci.2024.122487