@article {VENU2025134567,
	title = {Development of cation-exchange membranes using solvent-free 3D printing: Towards tailored surface topographies},
	journal = {Separation and Purification Technology},
	volume = {378},
	year = {2025},
	note = {n/a},
	pages = {134567},
	abstract = {<p>Electromembrane processes are employed in critical applications such as desalination, lithium recovery, and salinity gradient energy conversion. However, issues like fouling and concentration polarisation may limit their effectiveness. Profiled ion-exchange membranes offer several advantages over flat membranes, including improved fluid mixing, enhanced mass transfer, lower pressure drop (thus, lower energy consumption), and elimination of the spacer{\textquoteright}s shadow effect. Nonetheless, their preparation is considerably more complex than that of flat membranes. In this study, we pioneered the use of solvent-free fused deposition modelling (FDM) 3D printing to fabricate flat and profiled (chevron and stripe) cation-exchange membranes (CEMs). The functionalisation of the 3D-printed membranes into CEMs was achieved via sulfonation. The optimised electrical resistance and permselectivity of the prepared membranes were 10.7~{\textpm}~4 Ωcm2 and 97.3~{\textpm}~4~\%, respectively, after 14~h of sulfonation, closely matching commercial alternatives (e.g., FUMASEP FKB-PK-130, 9.7~{\textpm}~3 Ωcm2 and 96.7~{\textpm}~1~\%). Sulfonation durations exceeding 14~h increased the membranes{\textquoteright} electrical resistance due to the formation of sulfone cross-bridges that do not participate in cations{\textquoteright} exchange. Since FDM 3D printing is a solvent-free and additive manufacturing method, it significantly reduces waste during membrane fabrication, resulting in an E-factor value of 1.5. Therefore, this work opens a path toward customisable, scalable, and greener CEM production for electrochemical applications ranging from the recovery of critical raw materials and water desalination to renewable energy conversion.</p>
},
	keywords = {Additive manufacturing, Electrical resistance, Ion exchange membranes, Permselectivity, Profiled membranes, Sulfonation},
	issn = {1383-5866},
	doi = {https://doi.org/10.1016/j.seppur.2025.134567},
	url = {https://www.sciencedirect.com/science/article/pii/S1383586625031648},
	author = {Mekhna Venu and Claudia F. Galinha and Jo{\~a}o G. Crespo and Sylwin Pawlowski}
}
