Bottom-up Synthesis for Fabricating Defect-free Two-Dimensional MoS₂ Sieving Membranes

Advancing membrane technology is essential for tackling water scarcity and reducing the energy consumption associated with water treatment, thereby supporting environmental sustainability. Two-dimensional materials, particularly MoS₂, have emerged as promising candidates for high-performance desalination membranes [1,2] due to their superior stability and resistance to swelling compared to graphene oxide [3,4]. However, current fabrication methods for MoS₂ membranes face challenges such as defect formation, scalability issues, and time-consuming functionalization processes. Our study [5] introduces a novel, scalable, and efficient bottom-up synthesis for fabricating functionalized defect-free MoS₂ membranes. The single-step wet chemistry approach produces monolayer MoS₂ nanosheets with a uniform lateral size (~4 nm), ensuring perfect laminar stacking. This process eliminates the need for excessive exfoliation or centrifugation steps. The synthesized MoS₂ nanosheets were deposited on poly(ether sulfone) supports to form selective layers with controllable thickness. The membranes achieved excellent rejection (>99%) for various salts (NaCl, KCl, MgSO₄) in osmotic pressure experiments. The membranes were also stable and maintained >99% salt rejection over six days of continuous operation and remained intact after three months of water immersion. This performance was superior in terms of rejection and permeance compared to state-of-the-art MoS₂ membranes reported in the literature. Hence, this synthesis method addresses key limitations of existing MoS₂ membrane fabrication techniques, offering an efficient route to produce high-performance membranes.

[1] O. Opetubo, et al. , A mini-review on MoS₂ membrane for water desalination: Recent development and challenges, Nanotech. Reviews 12 (2023).

[2] Y. Liu, et al. , MoS₂-based membranes in water treatment and purification, Chem. Eng. J. 422 (2021) 130082.

[3] P. Oviroh, et al., Towards the realisation of high permi-selective MoS₂ membrane for water desalination, npj Clean Water 6 (2023) 14.

[4] S. Zheng, et al., Swelling of Graphene Oxide Membranes in Aqueous Solution: Characterization of Interlayer Spacing and Insight into Water Transport Mechanisms, ACS Nano 11 (2017) 6440–6450.

[5] S. Al-Nahari, et al. , Bottom-Up Synthesis for Defect-Free Two-Dimensional MoS₂ Sieving Membranes, ACS Applied Nano Materials 8 (2025) 5894–5899.