Selective ion transport in large-area graphene oxide membrane filters driven by the ionic radius and electrostatic interactions
Journal article, 2024
Filters made of graphene oxide (GO) are promising for purification of water and selective sieving of specific ions; while some results indicate the ionic radius as the discriminating factor in the sieving efficiency, the exact mechanism of sieving is still under debate. Furthermore, most of the reported GO filters are planar coatings with a simple geometry and an area much smaller than commercial water filters. Here, we show selective transport of different ions across GO coatings deposited on standard hollow fiber filters with an area >10 times larger than typical filters reported. Thanks to the fabrication procedure, we obtained a uniform coating on such complex geometry with no cracks or holes. Monovalent ions like Na+ and K+ can be transported through these filters by applying a low electric voltage, while divalent ions are blocked. By combining transport and adsorption measurements with molecular dynamics simulations and spectroscopic characterization, we unravel the ion sieving mechanism and demonstrate that it is mainly due to the interactions of the ions with the carboxylate groups present on the GO surface at neutral pH.
Author
Lidia Lancellotti
Consiglo Nazionale Delle Richerche
Antonio Bianchi
Consiglo Nazionale Delle Richerche
Alessandro Kovtun
Consiglo Nazionale Delle Richerche
M. Gazzano
Consiglo Nazionale Delle Richerche
Tainah Dorina Marforio
University of Bologna
Zhenyuan Xia
Chalmers, Industrial and Materials Science, Materials and manufacture
Matteo Calvaresi
University of Bologna
M. Melucci
Consiglo Nazionale Delle Richerche
Chiara Zanardi
Universita Ca' Foscari Venezia
Consiglo Nazionale Delle Richerche
Vincenzo Palermo
Universita Ca' Foscari Venezia
Consiglo Nazionale Delle Richerche
Nanoscale
2040-3364 (ISSN) 20403372 (eISSN)
Vol. 16 14 7123-7133Subject Categories
Physical Chemistry
DOI
10.1039/d3nr05874c
PubMed
38501609