(735az) Selective Separation of Precious Ions from Water By Mxene Free-Standing Membranes

Titanium carbide MXene free-standing membranes (MFMs) have garnered significant attention for their efficiency in ion separation from water, owing to their aligned nanochannels and unique surface chemistry. However, their application in the selective separation of precious ions is seldom and remains to be experimentally explored. In this study, we focused on adjusting the interlayer spacing of MFMs and, consequently, the size of their nanochannels to either match or exceed the diameter of the desired ions. This adjustment facilitates the permeation of precious ions, including Y²⁺, Cr²⁺, and Ce^2+, through the membrane while rejecting other ions, allowing for their selective separation. We investigated the correlation between membrane surface chemistry and ion selectivity, showcasing the potential of controlling MXene surface chemistry to enhance the efficiency of selective ion separation. Additionally, we extended the lifetime and stability of MFMs through in situ cross-linking via thermal treatment. Our findings pave the way for the practical implementation of these membranes in the selective separation of precious ions, a crucial process for technologies essential to fostering a circular economy and achieving a clean energy future.