Xing Yang, from the Department of Chemical Engineering, KU Leuven, and colleagues from other KU Leuven departments and Indonesia have published a new article in the Journal of Membrane Science on the synergistic effect between cation-π bonding and AC electro-deposition, which alters the polymerization dynamics and produces a more ordered membrane structure.
Effective recovery of valuable ion resources such as lithium is gaining increasing importance. Monovalent selective cation exchange membranes (MCEM) used in electrodialysis have shown great potential, but their development is hampered by the classical trade-offs related to membrane permeability, selectivity and energy efficiency. We reported a new route to design high performance MCEM, utilizing the synergy of ionic control (IC) through cation-π bonding of polydopamine (PDA) and alternating current (AC), which has not been reported before. A set of deliberately controlled membrane fabrication conditions were chosen, with different ionic control (i.e., no cation, K+, Li+) and with/without AC for systematic comparison. Combining with morphology & electrochemical measurements, the membrane with electro-assisted K control, i.e., PDAM-K+/AC, exhibited respective 72% and 51% higher Li and K transport rate, higher permselectivity of 9.54 (Li+/Mg2 ) and 17.86 (K+/Mg2 ), and 3.3-fold lower surface electrical resistance (SER) compared to other modified membranes (e.g., PDAM). Also, PDAM-K+/AC exhibited no sign of scaling, supported by its much increased limiting current density. The results supported the hypothesis of the synergistic effect between cation-π bonding and AC electro-deposition, which altered the polymerization dynamics and produced more ordered membrane structure. The control strategy showed a viable route to fabricate ion exchange membranes for imparting monovalent selectivity, reducing scaling and avoiding energy penalty.
Reference
Petric Marc Ruya, Yan Zhao, Samuel Eyley, Wim Thielemans, Alexander Volodine, I Gede Wenten, Xing Yang,
Harnessing ion resource recovery: design of selective cation exchange membranes via a synergistic ionic control method,
Journal of Membrane Science, 2024, 122844, ISSN 0376-7388, https://doi.org/10.1016/j.memsci.2024.122844.
Acknowledgements
his research is funded by the European Union (ERC, IonFracMem, 101076550). Disclaimer: Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. The authors would also like to acknowledge the funding support from the Global South Scholarship of KU Leuven ZB/21/019
