MXene Membranes Inserted with Tannic Acid Etched MOF Nanocrystals for Ultrafast Water Permeation: Elucidating the Water Transport Mechanism in Nanoconfined Interlaminar Channels

Utilizing pore and interlayer engineering within nanoconfined interlaminar channels represents an ingenious approach to design highly permselective MXene (Ti3C2TX) membranes. Herein, the tannic acid (TA) etched ZIF-8 (TZIF-8) nanocrystals with hollow structures were effectually inserted into the interlayer spacing of MXene membranes. First, the density functional theory (DFT) results demonstrated the reaction mechanism between TA and ZIF-8. Then, the underlying mechanism of enhanced water-adsorptive properties for MXene/TZIF-8 membrane was due to the higher binding energy of water/TZIF-8 system than that of water/ZIF-8 system, elucidated by molecular dynamic simulation. Furthermore, the low mass transfer resistance and abundant mass transfer pathways of the MXene/TZIF-8 membrane were comprehensively proved by various experimental conclusions, characterizations and simulation calculations. As a result, the optimal MXene/TZIF-8 membrane exhibited high water permeance and concurrently satisfactory separation efficacy toward various oil/water emulsions. This work is anticipated to deepen the comprehension of high-efficiency water transport along interbedded nanochannels in MXene membranes.