Simultaneous improvement of flux and monovalent selectivity of multilayer polyelectrolyte membranes by ion-imprinting

This study aims to fabricate monovalent cations selective membranes through Layer-by-Layer (LbL) assembly with ion-imprinting introduced. Nickel ions (Ni2+) were introduced into the polycation of polyethyleneimine (PEI) as template and then modified the ultrafiltration membrane through LbL assembly followed by glutaral-dehyde (GA) crosslinking and reduction. After eluting the template, ion-imprinting channels with specific size were formed in the modified layer. These channels enhanced the water flux with the selectivity for Na+/Mg2+ improved 2.25 times simultaneously compared to the non-imprinted membrane. Besides, the membrane prep-aration conditions were optimized and the optimum selectivity of 4.16 was achieved. We analyzed the mecha-nism of improving separation performance via ion-imprinting technology and believed that this environmental -friendly method provides a new road to fabricate monovalent selective membrane for seawater softening and lithium extraction from magnesium-rich brine.

Automated summary

This study fabricated monovalent cations selective membranes using Layer-by-Layer assembly and ion-imprinting technology, which showed improved water flux and selectivity for seawater softening and lithium extraction from magnesium-rich brine.