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Enhancing Surface Charge Density of Graphene Oxide Membranes through Al(OH)4- Anion Incorporation for Osmotic Energy Conversion
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  • Anna Aixalà-Perelló,
  • Federico Raffone,
  • Luisa Baudino,
  • Alessandro Pedico,
  • Mara Serrapede,
  • Giancarlo Cicero,
  • Andrea Lamberti
Anna Aixalà-Perelló
Politecnico di Torino

Corresponding Author:anna.aixala@polito.it

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Federico Raffone
Politecnico di Torino
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Luisa Baudino
Politecnico di Torino
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Alessandro Pedico
Politecnico di Torino
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Mara Serrapede
Politecnico di Torino
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Giancarlo Cicero
Politecnico di Torino
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Andrea Lamberti
Politecnico di Torino
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Abstract

This study explores enhancing salinity gradient power using 2D materials due to their surface-governed charge. However, achieving high-performing membranes with superior ion selectivity and low ionic resistances remains challenging. To address this issue, Al(OH)4- anions were incorporated into graphene oxide membranes to increase their spontaneous negative surface charge. The anions were successfully formed and encapsulated through a reaction with the alumina support under alkaline conditions during the membrane formation. The membranes’ physicochemical properties were analyzed by means of selected characterization techniques. The incorporation of Al(OH)4- anions significantly improved permselectivity and ionic resistance, reaching approximately 95% and 2 Ω cm2, respectively. A modeling of the system was carried out to further understand the anchoring of these ions within the membrane matrix and their role in boosting the charge of the membrane and, therefore, their electrochemical properties. The study delved into the utilization of GO membranes as monovalent-selective membranes, an approach to boost reverse electrodialysis power densities. The membranes demonstrated impressive selectivity, overcoming 70 folds for divalent cations over K+.
17 Oct 2023Submitted to Energy & Environmental Materials
18 Oct 2023Submission Checks Completed
18 Oct 2023Assigned to Editor
19 Oct 2023Review(s) Completed, Editorial Evaluation Pending
25 Oct 2023Reviewer(s) Assigned