Understanding the Role of Microstructure in Ti₃C₂T_x MXene Membrane Performance

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Titanium carbide (Ti₃C₂T_x) MXene membranes show promise for separation technologies due to tunable interlayer channels.
• Reported water permeability varies widely, indicating unaddressed factors influencing transport.

Purpose of the Study:

• To investigate the roles of dynamic MXene membrane microstructure under pressure and MXene flake size in water transport.
• To understand the factors affecting water flux in MXene-based separation membranes.

Main Methods:

• Fabrication of Ti₃C₂T_x MXene membranes with varying flake sizes.
• In-situ observation and analysis of membrane microstructure changes under applied pressure during filtration.
• Measurement of water permeability across membranes with different flake sizes and microstructures.

Main Results:

• Water permeability significantly declines under pressure due to membrane compaction, from tens to below 5 L/m²·bar·h.
• The observed microstructural changes are reversible upon drying.
• Smaller MXene flake sizes lead to higher water permeability by reducing pathway tortuosity.

Conclusions:

• Both dynamic microstructural evolution under pressure and MXene flake size are critical determinants of water flux.
• Rational design of MXene membranes for separation requires consideration of these microstructural and dimensional factors.
• Findings provide insights for optimizing MXene membrane performance in liquid separation applications.