MXene Nanosheet Templated Nanofiltration Membranes toward Ultrahigh Water Transport

Abstract

The demand for thin-film composite (TFC) nanofiltration membranes with superior permeance and high rejection is gradually increasing for seawater desalination and brackish water softening. However, improving the membrane permeance remains a great challenge due to the formation of excrescent polyamide in the substrate pores and thick polyamide film. Herein, we fabricated a highperformance TFC nanofiltration membrane via a classical interfacial polymerization reaction on a two-dimensional lamellar layer of transition-metal carbides (MXene). The MXene layer promoted the absorption of the reactive monomer, and higher amine monomer concentration facilitated the self-sealing and self-termination of interfacial polymerization to generate a thinner outer polyamide film from 68 to 20 nm. The almost nonporous lamellar interface inhibited the formation of inner polyamide in the substrate pores. In addition, the MXene lamellar layer could be eliminated by mild oxidation after interfacial polymerization to avoid imparted additional hydraulic resistance. The resulting TFC membrane conferred a high rejection above 96% for Na 2 SO 4 and excellent permeance of 45.7 L•m −2 •h −1 •bar −1 , which was almost 4.5 times higher than that of the control membrane (10.2 L•m −2 •h −1 •bar −1 ). This research provides a feasible strategy for fabricating a high-performance nanofiltration membrane using two-dimensional nanosheets as a templated interface.

Recent Progress in Emerging Two-Dimensional Transition Metal Carbides

“…Recently, TMCs have also been used to fabricate nanofiltration membranes due to its uniform nanopores. The TMCs-based nanofiltration membranes show extraordinary [218]. Due to its high electrical conductivity and high light adsorption, TMCs have also been used in electromagnetic shielding.…”

Two-Dimensional Transition Metal Carbides and Nitrides (MXenes) for Water Purification and Antibacterial Applications

“…Therefore, researchers focus on introducing novel materials to enhance the antifouling property of the membrane to save energy and the operational cost. Recently, MXene-based membranes have been widely used for wastewater treatment, water purification, and desalination applications, as shown in Table 1 [71][72][73][74][75][76][77][78][79][80][81][82]. Initial work by Gogotsi et al [63] demonstrated 2D MXene-based membranes with PVDF supported particular ion separations; for instance, Mg 2+ , Ca 2+ , Li + , Al 3+ , Ni 2+ , Na + , and K + .…”

CNTs Intercalated LDH Composite Membrane for Water Purification with High Permeance

“…However, the separation performance of these polymeric membranes, and especially their permeance, needs to be further improved [ 26 ]. Two-dimensional (2D) materials—e.g., graphene oxide (GO) [ 27 ], molybdenum disulfide (MoS 2 ) [ 28 ], layered double hydroxide (LDH) [ 29 ], and MXene [ 30 ]—are thus widely employed in membrane fabrication considering their superior water transport and ion selectivity properties. Among all these 2D materials, LDH possesses the advantages of tunable layer spacing and versatile surface properties and microstructures via its combinations of positively charged laminates and interlayer anions [ 31 , 32 ].…”