Laminar Graphene Oxide Membranes Towards Selective Ionic and Molecular Separations: Challenges and Progress

Abstract

Resolution of resources and environmental crises requires an efficient separation technologies, consequently, scientists and engineers are working vigorously for ideal separation materials. Laminar graphene oxide (GO) is a two-dimensional (2D) material offers considerable interest in this field due to its single atomic layer thickness, good stability, chemical inertness, and variety of functional groups. Recently, GO have emerged as a novel membrane material for molecular and ionic separation of gases, solvent, water, and desalination applications. This tutorial review aims to discuss the various approaches used to control the stacking of GO-based membrane with emphasis of advantages and drawbacks associated with each approach. Further, attention will also be given to describe the recent progress in GO based membranes for ionic and molecular separations. Meanwhile, challenges and opportunities will also be discussed in detail. We hope this review expected to provide a compact source of information that will be of great interest to chemists, material scientists, physicists, and engineers working or planning to work in GO based membranes for separation applications.

Smart Two‐Dimensional Membranes for Molecular Separations

“…Some 2D membranes tend to fail under high pressures, temperatures, or in aqueous solutions. [38] Most of the previous investigations occur at low pressures and temperatures to prevent the membranes from deteriorating. Moreover, smart 2D membranes may be exposed to acidic gases such as H 2 S/SO 2 / NO 2 in industrial cryogenic or aromatic recovery systems.…”

Recent Advances in MXene‐based Separation Membranes

“…From these studies, it is clear that Mxene‐based membranes are mostly prepared through vacuum filtration assembly. Beside several advantages the vacuum filtration method requires large volumes of liquid, long duration, and is difficult to scale up 15. Therefore, the fabrication of large‐area, defect‐free, and pore‐size controlled Mxene‐based membranes is of most importance for large scale applications with superior separation performance.…”

“…Carbon nanotubes (CNTs) have been widely studied for NF applications with high separation efficiency due to their tunable microstructural properties, but unfortunately such membranes cannot gain more attention for large scale applications due to lower permeability and stability 5. Additionally, 2D materials such as graphene, GO, h‐BN, TMDCs, COFs, and MOFs have been widely investigated for water purification, desalination, gas separation, and pervaporation applications due to their exceptional properties 10–18. Among these, GO is considered as effective material for membrane technology and most efforts have been devoted to improve the separation efficiency and permeability along with stability 19.…”

Advantages, limitations, and future suggestions in studying graphene-based desalination membranes

“…Many different production methods for small samples are proposed, for example. [73][74][75][76] Recent reviews on GO membranes 77,78 describe their fabrication methods such as vacuum/pressure ltration method, drop-cast, spin-coating, layer by layer (LBL) assembly. One of the most scalable methods is the shear alignment of discotic liquid crystals of GO.…”