The effect of D-spacing on the ion selectivity performance of MXene membrane

The effect of D-spacing on the ion selectivity performance of MXene membrane



Two-dimensional materials
Ion selective membrane


2-D materials with nanofluidic channels have gained significant attention for their potential as an ion separation membrane. However, the fundamental understanding of the interactions between nanochannel sizes and ion selectivity and conductivity remains complex as experimentally controlling the free interlayer spacing in sub-nanometer scales is challenging. Herein, we utilize molecular dynamic (MD) simulations to tailor the free interlayer spacing between a model 2-D MXene membrane to understand their effects on ion transport behaviour. As a validation, the free interlayer spacing of the MXene nanosheets was altered by impregnating different type of ions, which is then used in an electrically driven ion separation system. The simulation result shows that as the free interlayer spacing increases from below to above 6 Å, the selectivity of monovalent Li+ and K+ compared to Mg2+ decreases due to the reduced entrance energy barrier for Mg2+; however, higher overall ionic conductivity can be achieved. The experimental data using a membrane with free interlayer spacing between 6 and 7 Å agrees well with the simulation study. The difference in the ion permeation of H+, K+, Na+, Li+, Ca2+, and Mg2+ was not only attributed to the nanochannel size but also considering the degree of ion dehydration and ions interactions to the –O binding site of the membrane. Further investigations demonstrated that ion transport mechanism through MXene nanochannels followed the surface-charge-governed behaviour in HCl and KCl solutions at different concentrations, as evident from significantly higher ionic and proton conductivity at low concentrations (<10-3 M) compared to the bulk solutions. This work leads to a better understanding of 2-D nanochannel design in ion transport applications.

We appreciate your valuable comments on this article

Leave a Comment:

Your email address will not be published. Required fields are marked *

Fill out this field
Fill out this field
Please enter a valid email address.

Biodegradable polymers and their nano-composites for the removal of endocrine-disrupting chemicals (EDCs) from wastewater: a review


Ultrafast and stable planar photodetector based on SnS2 nanosheets/perovskite structure


Efficient Sorbitol Producing Process through Glucose Hydrogenation Catalyzed by Ru Supported Amino Poly (Styrene-co-Maleic) Polymer (ASMA) Encapsulated on ?-Al2O …


An electrochemical strategy for toxic ractopamine sensing in pork samples; twofold amplified nano-based structure analytical tool

TiN formation on Ti target by laser ablation method under different N2 gas pressure and laser scanning cycles: A wettability study
Laser-assisted synthesis of bentonite/Pd nanocomposite and its electrochemical hydrogen storage capacity