Vacancy Functionalized MoS₂ Nanolaminated Membranes for Efficient Sieving in Forward Osmosis

Area of Science:

• Materials Science
• Nanotechnology
• Environmental Science

Background:

• Two-dimensional transition-metal dichalcogenides (TMDs) show potential for water purification.
• Fabricating nanolaminate membranes with controllable nanochannel dimensions is a significant challenge.

Purpose of the Study:

• To develop a sulfur vacancy functionalization strategy for creating high-performance nanolaminate membranes.
• To investigate the effect of thiol grafting on MoS2 nanosheets for water purification.

Main Methods:

• Functionalization of MoS2 nanosheets with three thiol-containing molecules (Cysteine, 3-Mercapto-1,2-propanediol, 1-Propanethiol).
• Fabrication of nanolaminate membranes using functionalized MoS2.
• Testing membrane performance in forward osmosis for salt rejection and water/salt selectivity.
• Utilizing numerical simulations to understand nanofluidic properties.

Main Results:

• Propanethiol functionalized MoS2 membranes achieved 99.3% salt rejection and 800 bar⁻¹ water/salt selectivity.
• Functionalization increased capillary width from 0.2 Å to approximately 5 Å.
• Simulations indicated that water-nanofluidic interactions and interlayer distance govern membrane properties.
• Grafting molecules repaired sulfur vacancies, enhancing membrane stability and minimizing swelling.

Conclusions:

• Sulfur vacancy functionalization is an effective strategy for fabricating high-performance nanolaminate membranes for water purification.
• The propanethiol functionalized MoS2 membrane demonstrates excellent salt rejection and selectivity.
• Improved membrane stability and tunable nanochannels offer promising prospects for practical water treatment applications.