Controlled fabrication and optimisation of crosslinked graphene oxide membranes for enhanced water purification performance

Kandjou, Vepika (2020) Controlled fabrication and optimisation of crosslinked graphene oxide membranes for enhanced water purification performance. Doctoral thesis, University of East Anglia.

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Abstract

Graphene Oxide (GO) is an equitable next generation membrane material and significant graphene alternative owing to its large-scale production scalability specifically and physicochemical characteristics. The use of GO as a water purification and desalination membrane was first demonstrated by Nair et al in 2012. As such, its feasibility as a nanofiltration separation membrane material is still in its primary usage hence the need for optimisations, modifications and understanding of its permeation mechanisms.

Major limitations in the use of GO as a separation membrane material include the widening of the membrane interlayer spacing (pore-gap) during operation and poor membrane stability. This doctoral research in consequence looked into the use of different crosslinkers to enhance the performance and stability of GO membranes through both inter and intralayer crosslinking. Successively, p-Phenylenediamine, 1,3,5–triazine – 2,4,6 triamine (melamine) and polyethyleneimine were systematically introduced onto the GO nanosheets via the dip-assisted layer-by-layer method to fabricate crosslinked GO membranes.

Principally, the feasibility of the use of the aforementioned crosslinkers in interconnecting GO nanosheets and fabricating thin-films/membranes via the layer by layer assembly method was explored. The nature of interaction between GO and the crosslinkers was analysed and subsequently crosslinked thin films were fabricated to demonstrate the control of key characteristics like thickness. Respective characterizations were undertaken, proving successful thin-film assembly. Following thin film fabrication, the thesis goes on to look into the nanofiltration performance of respective membranes assembled on poly (acrylonitrile) and polycarbonate substrates. The impact of crosslinking in enhancing performance was apparent. Successively, the impact of the physicochemical properties of GO, specifically its lateral size and surface chemistry onto the nanofiltration performance of the crosslinked membranes was studied. Ultimately, GO and crosslinker concentration alteration on membrane nanofiltration performance was analysed. These were optimisation stages where the aim was to determine the optimum lateral-size of GO nanosheets and concentration effects in membrane stability and performance.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science
Depositing User: Chris White
Date Deposited: 14 Apr 2021 10:14
Last Modified: 14 Apr 2021 10:14
URI: https://ueaeprints.uea.ac.uk/id/eprint/79741
DOI:

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