Enhanced antipressure ability through graphene oxide membrane by intercalating g‐C₃N₄ nanosheets for water purification

Abstract

Graphene oxide (GO) membranes have shown great potential for water purification, but their permeability and antipressure ability are poor, which limits their practical applications. In this study, two‐dimensional graphitic carbon nitride (g‐C3N4) nanosheet‐intercalated GO (GOCN) membranes were developed to improve the separation performance of GO membranes, especially under high operating pressure. After incorporation of the g‐C3N4 nanosheets, the amount of permeable nanochannels (wrinkles or corrugation) in the membrane increased; hence, the water permeance was effectively improved (twice as high as that of GO membranes). Moreover, the antipressure performance of the GOCN membranes was significantly enhanced (even below 0.5 MPa pressure) as the nanochannels in the composite membranes become stable and rigid due to the support of the pressure‐resistant g‐C3N4 nanosheets. The good separation performance demonstrates that the intercalation of g‐C3N4 is an effective strategy to improve the GO‐based membrane properties, which can promote their application in water purification.

Confined assembly of ultrathin nanoporous nitrogen-doped graphene nanofilms with dual metal coordination chemistry

“…Among these membranes, the ultrathin GCN-3 membrane (53 nm) displayed a significantly high water permeance of 210 L m −2 h −1 bar −1 together with satisfactory rejection of 99.8% for NgB, surpassing most previously reported GO-based and polymeric ultrathin membranes with thickness lower than 100 nm for water purification ( Figure 4 A and Table S2 ) ( Yang et al. 2019a , 2019b ; Morelos et al., 2017 ; Xu et al., 2019 ; Wang et al., 2019b ; Nam et al., 2019 ; Liu et al., 2019 ; Soyekwo et al., 2017 ; Lin et al., 2018 ; Shen et al., 2019 ; You et al., 2019 ). To further determine the ultrafast molecular sieving properties of ultrathin nanofiltration membranes, dye molecules with different sizes and charges were used as molecular probes to characterize the selectivity owing to their easy detection, good solubility, and broad choice.…”

The stability of a graphene oxide (GO) nanofiltration (NF) membrane in an aqueous environment: progress and challenges

“…the GO selective layer can be precisely modulated by adjusting the interlayer spacing between the GO layers. [23][24][25][26][27] The nanochannels in the ultrathin selective layer, as well as the nanopores on the GO sheets, can endow the GO-based NF membrane with ultrahigh water permeation flux that is orders of magnitude higher than that of traditional polymer-based NF membranes. [28][29][30][31] The precisely adjustable nanochannels of the GO-based selective layer can realize precise molecular sieving as needed.…”

Dehydration of C2–C4 alcohol/water mixtures via electrostatically enhanced graphene oxide laminar membranes

“…Inorganic materials such as zeolites 8 and metal–organic frameworks 9 have shown excellent separation performance for solvent dehydration, and the large‐scale fabrication of defect‐free membranes would further promote the use of inorganic membranes in the chemical industry 10 . As an emerging alternative membrane material, graphene oxide (GO), which has a single‐layer structure offers great potential to minimize the membrane thickness and, thus, maximize the permeance 1,11‐13 . Moreover, the functional groups (e.g., epoxy groups, hydroxyl groups, and carboxyl groups) of GO can be chemically modified 14 during membrane fabrication, thus forming water transport channels between the GO nanosheets 15 …”

“…Various strategies have been proposed to regulate the interlayer structure of GO membranes to achieve selective water transport 1,12 and improve their structural stability 13 in water. Among them, crosslinking is the most widely studied approach 22 .…”

“…18 Thus, precision assembling and tuning of the interlayer structure of GO membranes are critical to improve the membrane stability and separation performance. [19][20][21] Various strategies have been proposed to regulate the interlayer structure of GO membranes to achieve selective water transport 1,12 and improve their structural stability 13 in water. Among them, crosslinking is the most widely studied approach.…”