2D Nanosheets and Their Composite Membranes for Water, Gas, and Ion Separation

Abstract

Two‐dimensional nanosheets have shown great potential for separation applications because of their exceptional molecular transport properties. Nanosheet materials such as graphene oxides, metal–organic frameworks, and covalent organic frameworks display unique, precise, and fast molecular transport through nanopores and/or nanochannels. However, the dimensional instability of nanosheets in harsh environments diminishes the membrane performance and hinders their long‐term operation in various applications such as gas separation, water desalination, and ion separation. Recent progress in nanosheet membranes has included modification by crosslinking and functionalization that has improved the stability of the membranes, their separation functionality, and the scalability of membrane formation while the membranes’ excellent molecular transport properties are retained. These improvements have enhanced the potential of nanosheet membranes in practical applications such as separation processes.

Ion Transport in Nanofluidic Devices for Energy Harvesting

“…provide the possibility to enhance both power density and membrane size for practical applications. [45][46][47] 2D materials have been widely used as building blocks for separation membranes, 48 in which efficient rejection by steric effects occurs, as well as electrochemical capacitors. In this way, the enhancement of ion transport is achieved in slit-shaped 2D nanochannels.…”

2D nanosheet enabled thin film nanocomposite membranes for freshwater production – a review

“…[19][20][21][22] Challenges associated with the fabrication, scale-up and commercialization of some of these materials have been discussed. [23][24][25] Laminar membranes, assembled solely by stacking 2D nanosheets, 26 exhibit similar performance profiles as TFN membranes, and several reviews on laminar and 2D-enabled mixed matrix membranes have also broadly focused on advanced synthetic pathways and their applications for liquid, gas and ion separation. 25,27 Yet, despite the potential of laminar membranes, TFN membranes appear currently better suited in the short term to serve commercial needs and tackle current separation challenges, since they offer more scalable and cost-effective solutions compared to laminar membranes.…”

“…[23][24][25] Laminar membranes, assembled solely by stacking 2D nanosheets, 26 exhibit similar performance profiles as TFN membranes, and several reviews on laminar and 2D-enabled mixed matrix membranes have also broadly focused on advanced synthetic pathways and their applications for liquid, gas and ion separation. 25,27 Yet, despite the potential of laminar membranes, TFN membranes appear currently better suited in the short term to serve commercial needs and tackle current separation challenges, since they offer more scalable and cost-effective solutions compared to laminar membranes. 25,28 The composition, structure and selection criteria of nanomaterial based fillers for TFN membranes was briefly discussed along with its application in gas and liquid separation.…”

“…25,27 Yet, despite the potential of laminar membranes, TFN membranes appear currently better suited in the short term to serve commercial needs and tackle current separation challenges, since they offer more scalable and cost-effective solutions compared to laminar membranes. 25,28 The composition, structure and selection criteria of nanomaterial based fillers for TFN membranes was briefly discussed along with its application in gas and liquid separation. 29 A recent review paper put together a discussion on different nanosheet embedding strategies and the impact of the processes on the performance of the membranes.…”

2D Nanocomposite Membranes: Water Purification and Fouling Mitigation

“…Such 2D nanomaterials are so-called nanosheets and they are characterized by their high surface areas and an atomic thickness that exposes all of the ions to the surface, thus enabling electronic coupling [ 25 ]. Their fabrication methods, performances, and separation mechanisms as membrane materials have been thoroughly surveyed [ 26 , 27 ]. In general, the behavior of nanomaterials differs from that of bulk materials and depends on the particular nanostructure [ 28 ].…”