Recent Advances in Graphene Oxide Membranes for Nanofiltration

Abstract

Advanced membrane separation technology plays an important role in achieving excellent water treatment, which can help solve the freshwater crisis. However, there remains a trade-off between membrane permeability and selectivity. An emerging candidate to address this issue is graphene oxide (GO), a two-dimensional (2D) laminated graphene derivative with abundant oxygen functional groups. Furthermore, the transport channels of GO-based membranes can be artificially modified and manipulated, exhibiting great promise for GO in the field of water purification and molecular separation. This review comprehensively summarizes the research advances on 2D GO-based membranes for high-performance nanofiltration (NF). It begins with an elaboration on the preparation methods of GO-based membranes, followed by a detailed summary of the chemical modification and physical manipulation of transport channels. Then we reviewed the current research progress of theoretical calculation and molecular dynamics simulation. Also, the high NF performance of GO-based membranes is presented. Finally, the remaining challenges and future prospects in order to develop advances in membrane technology are provided.

Graphene Oxide Nanofiltration Membrane Based on Three-Dimensional Size-Controllable Metal–Organic Frameworks for Water Treatment

“…Graphene oxide (GO), an important derivative of the graphene family, is of particular interest for water treatment due to its ultrathin structure, large specific surface area, and abundant oxygen-containing functional groups. 17,18 The basic mechanisms of GO nanofiltration membranes, including sieving effects, surface effects, electrical effects, and channel− guest interactions, rely on confined mass transport at the nanoscale, especially below 10 nm. 19−22 Typically, the interlayer empty spacing of 2D channels formed by stacking GO layers is ∼5.6 Å in a dry state, only allowing the transport of one or two layers of water molecules.…”

“…Two-dimensional (2D) materials based ultrathin membrane composed of two-dimensional (2D) materials with molecular selective nanochannels are one of the most promising candidates for water treatment. Graphene oxide (GO), an important derivative of the graphene family, is of particular interest for water treatment due to its ultrathin structure, large specific surface area, and abundant oxygen-containing functional groups. , The basic mechanisms of GO nanofiltration membranes, including sieving effects, surface effects, electrical effects, and channel–guest interactions, rely on confined mass transport at the nanoscale, especially below 10 nm. − Typically, the interlayer empty spacing of 2D channels formed by stacking GO layers is ∼5.6 Å in a dry state, only allowing the transport of one or two layers of water molecules. Under wet conditions, the swelling effect of GO channels increases the interlayer spacing, which limits high selectivity because spacing will be sufficient to block the precise separation of small ions or molecules.…”

Review of 2D Graphitic Carbon Nitride-Based Membranes: Principles, Syntheses, and Applications

“…Widely investigated 2D materials for membrane separation include graphene oxide (GO), transition metal carbides and nitrides (MXenes), metal–organic frameworks (MOFs), covalent organic frameworks (COFs), and graphitic carbon nitride (g-C 3 N 4 ). Among them, GO has gained considerable attention in membrane filtration and water treatment. − However, the pore structures on GO surfaces are nonuniform because they are defects introduced by chemical treatments of graphite using strong oxidants and acids. The high adsorption capacity of GO nanosheets for organic contaminants also causes fouling.…”

Advances in Bioinspired Triboelectric Nanogenerators

“…[180][181][182][183][184][185][186][187][188] For example, nanostructures can affect a material's mechanical or steric properties, thermal and electrical conductivity, optical absorption, and melting point. [189][190][191][192][193][194][195][196][197] In addition, macrostructures such as the morphologies of hummingbird wings, [30] fish gills, [198] and fish scales [199] can inspire the organization of a TENG's electrodes. Although mimicking these structures in a TENG may not provide the same unique characteristics like breathing underwater or hovering in the air, these structures can provide valuable inspiration for unique electrode configurations that can widen the scope of energies that TENGs can harvest and increase their output parameters.…”