Molten Salt Intercalated MXene Membrane for d-Spacing Stabilization under Electrochemical Assistance

Conductive membranes have gained great interest for water andwastewater treatment and have demonstrated enhanced permeability andfouling resistance under electrochemical assistance. In particular,the lamellar membranes assembled by two-dimensional (2D) materialssuch as graphene or MXenes are attractive due to the characteristicsof high permeability and precise molecular sieving. However, the swellingproblem of 2D membranes has not been adequately addressed and willbe even worse in the electric fields, leading to weakened sievingperformance. This study presented a molten salt intercalation methodvia vacuum hot pressing for the fabrication of an Al3+-intercalatedMXene membrane with good antiswelling ability. X-ray photoelectronspectroscopy (XPS) analysis revealed a significant increase in theAl-O group and Al content of the intercalated MXene membrane.In situ XRD tests confirmed that Al3+ intercalation contributedto the d-spacing stability at dynamic voltages. Themembranes displayed exceptional separation efficacy for organic dyesand antibiotics with rejection rates exceeding 90%. This work advancesour understanding of the intercalation mechanism and membrane performanceoptimization and represents a step forward in enhancing the scalabilityof the membranes for practical applications in water treatment.

Automated summary

This study presents a molten salt intercalation method for the fabrication of an Al3+-intercalated MXene membrane with good antiswelling ability. The intercalated membrane shows significant increase in the Al-O group and Al content, while in situ XRD tests confirm the stability of d-spacing with Al3+ intercalation. The membranes demonstrate excellent separation efficacy for organic dyes and antibiotics with rejection rates exceeding 90%.