Synergetic effect of physicochemical and electrostatic strategies on ion sieving for polymer cross-linked graphene oxide membranes

Abstract

Layered-stacked graphene oxide (GO) membranes have shown ultrafast water permeability and ion selectivity by virtue of well-defined nanochannels and intrinsic surface charge properties; however, accumulating water molecules in GO capillaries...

Horizontally Asymmetric Nanochannels of Graphene Oxide Membranes for Efficient Osmotic Energy Harvesting

“…The N 1s spectra of the EGO membranes parallel these results (Figure S4). − For the wide channel on EGO-5 and EGO-10 membranes, the amount of nitrogen is estimated as 2.46 and 3.91 at. %, respectively, whereas nitrogen is rarely detected on the narrow side, which implies that the EDA vapor does not penetrate the entire channel.…”

“…This indicates that the vapor reaction on the wide channel side chemically reduces the channel. 24,25 EGO-10-N shows a significantly decreased C=O ratio compared to EGO-5-N, possibly due to the increased vapor reaction time. EGO-10-W exhibits a substantially increased C−OH, C−O−C, C−N bonding ratio, suggesting that EDA molecules are successfully functionalized to the GO layer via a nucleophilic reaction.…”

Interfacially designed magnetic nanoparticles as Fenton-like catalyst for efficient chemical cleaning of polyamide nanofiltration membranes

“…Nanofiltration (NF) has been widely used in wastewater treatment, food processing, and resource recovery attributed to its low energy consumption and environmentally friendliness. [1][2][3][4][5] During the separation process, however, foulants easily adsorb/deposit on/into the membrane, resulting in severe flux decline and selectivity alteration. [6][7][8][9] Membrane fouling mainly includes three categories: foulant adsorption, cake layer formation, and pore blocking.…”

Facile Fabrication of Defect-Controlled Graphene Oxide Membrane through Shear-Induced Alignment for Regulating Ion Transport

“… 13 , 14 Although most studies have focused on the physicochemical modification of GO sheets by introducing additional functional groups or electrostatic moieties, the separation performance of the GO membrane is highly affected by the layer-stacked structures. 15 , 16 Therefore, it is imperative to develop stacking methods for the well-aligned laminated structure without nanopores and wrinkles that can deteriorate the membrane selectivity.…”

“…Although it is difficult for a conventional membrane with nanoscale-pores to control the transport of angstrom-scale species such as monovalent ions, the development of two-dimensional (2D) material-based assembly methods makes it possible to effectively manipulate the penetration of such small atomic and ionic species through subnanometer interlayer channels. − Graphene oxide (GO), one of the 2D building blocks, is widely utilized for the membrane separation process due to the structural versatility as well as subnanoscale interlayer channels. , In addition, as the GO layer has a high surface area with flexible 2D graphitic structures, the GO membrane can be easily fabricated by simple filtration methods via self-assembly. , For the application in desalination and water purification, the GO membrane allows water molecules to be easily agglomerated in the hydrophilic region via hydrogen bonding with oxygen functional groups, while simultaneously they can rapidly pass through the hydrophobic region with almost no friction, resulting in superior water permeability. , Although most studies have focused on the physicochemical modification of GO sheets by introducing additional functional groups or electrostatic moieties, the separation performance of the GO membrane is highly affected by the layer-stacked structures. , Therefore, it is imperative to develop stacking methods for the well-aligned laminated structure without nanopores and wrinkles that can deteriorate the membrane selectivity.…”