Enhanced covalent p-phenylenediamine crosslinked graphene oxide membranes: Towards superior contaminant removal from wastewaters and improved membrane reusability

Abstract

Dip coating and Layer-by-layer have been proven as effective deposition methods. Uncrosslinked and PPD crosslinked GO membranes have been successfully fabricated. Crosslinker impact is significant in enhanced membrane separation performance. Up to 100% MB contaminant removal was achieved for crosslinked membranes. PPD-GO crosslinked membranes are suitable to reuse for multiple cycles.

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

“…3B). [49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66] Furthermore, glutaraldehyde 67 and 1-allyl-3-vinylimidazolium chloride 68 have also been utilized as cross-linking agents to improve the stability of the GO membrane in water. Although covalent cross-linking can endow the GO membranes with enough stability in water, the excessive cross-linking will disturb and block water transport within the GO nanochannels, leading to the decrease of the water flux of the membrane.…”

Interfacial crosslinked controlled thickness graphene oxide thin-films through dip-assisted layer-by-layer assembly means

“…The positively charged glass slides were then rinsed in deionized water and then dried before dip-assisted layer-by-layer assembly, which commenced with immersion in the negatively GO dispersion (Figure 1 Table 1). Based on previous experience [15,22], other dip-assisted layer by layer operating conditions like the immersion and withdrawal speeds were kept constant at…”

“…Although its mechanical and electrical properties are not as outstanding as those of graphene, in some applications like sensors and separation membranes the properties of GO are sufficient. This makes it a notable graphene substitute pertaining to these applications [22][23][24][25][26][27]. Another key advantage of GO is its containment of oxygenated functional groups; the epoxy, hydroxyl and carboxylic groups, which make the material chemically active [28,29].…”

Influence of graphene oxide's characteristics on the fabrication and performance of crosslinked nanofiltration membranes

“…In this context, graphene oxide (GO) arises as a very promising graphene substitute due to its ability to be cost effectively fabricated from graphite [16][17][18]. Though not mechanically as strong as graphene, the presence of oxygenated functional groups on its surface lends hydrophilicity, which strengthen its potential use as a water purification membrane material [19][20][21]. Moreover, thin GO films advantageously offer a unique tortuous water flow channel that is responsible for a faster water flow relative to other nanomaterials [22].…”

“…However, the loss of membrane hydrophilicity comes with the need of a higher operation pressure and increased membrane susceptibility to fouling [27][28][29]. Other approaches, such as the incorporation of crosslinkers, have been also explored to control the inter-flake gap and in this way optimising permeation abilities [19].…”