Fabrication and aplications of graphene hollow fibre membranes
File(s)
Author(s)
Chi, Yunsi
Type
Thesis or dissertation
Abstract
Graphene has attracted vast amount of research in the last decade. Attributed to its sp2 hybridisation, graphene is chemically inert, making it an ideal material to be used in extremely harsh conditions. Graphene’s ultra-thin property also makes it an ideal material for membrane separation because permeation is inversely proportional to membrane thickness. While many studies have been carried out on graphene membranes, scaling up remains a key challenge, designing graphene membrane in a geometry which favours module assembly is strongly desired. Furthermore, chemical resistance of metallic membrane can be improved by integrating graphene as a protective barrier. In this thesis, the fabrication and applications of the prepared graphene hollow fibre membranes are explored.
Firstly, graphene protected nickel hollow fibre membrane was developed and demonstrated improved chemical resistance compared to the non-protected membrane. Its application was further explored in the production of nanoparticles. Pristine graphene membranes supported on porous ceramic hollow fibre was successfully prepared via the sacrificial layer assisted chemical vapour deposition (CVD) approach. A dense metal sacrificial layer was deposited on the hollow fibre support using electroless plating. After successful graphene growth, this sacrificial layer was removed while the ceramic hollow fibre remained intact to act as the support. Both copper and nickel sacrificial layers were explored. When copper was used, copper dewetting on ceramic surface was observed during high temperature synthesis, which hindered good quality graphene growth. The membrane showed compaction where the permeation flux declined during filtration. Nickel was then investigated to prevent metal dewetting. A dense and continuous nickel sacrificial layer was formed, which was suitable for high-quality CVD graphene synthesis. Finally, pristine graphene membrane supported on ceramic hollow fibre was realised after metal etching, demonstrating reasonable flux and rejection. This study thus presents the successful engineering of graphene hollow fibre membranes suitable for industry scale-up.
Firstly, graphene protected nickel hollow fibre membrane was developed and demonstrated improved chemical resistance compared to the non-protected membrane. Its application was further explored in the production of nanoparticles. Pristine graphene membranes supported on porous ceramic hollow fibre was successfully prepared via the sacrificial layer assisted chemical vapour deposition (CVD) approach. A dense metal sacrificial layer was deposited on the hollow fibre support using electroless plating. After successful graphene growth, this sacrificial layer was removed while the ceramic hollow fibre remained intact to act as the support. Both copper and nickel sacrificial layers were explored. When copper was used, copper dewetting on ceramic surface was observed during high temperature synthesis, which hindered good quality graphene growth. The membrane showed compaction where the permeation flux declined during filtration. Nickel was then investigated to prevent metal dewetting. A dense and continuous nickel sacrificial layer was formed, which was suitable for high-quality CVD graphene synthesis. Finally, pristine graphene membrane supported on ceramic hollow fibre was realised after metal etching, demonstrating reasonable flux and rejection. This study thus presents the successful engineering of graphene hollow fibre membranes suitable for industry scale-up.
Version
Open Access
Date Issued
2019-09
Date Awarded
2020-02
Copyright Statement
Creative Commons Attribution NonCommercial Licence
Advisor
Li, Kang
Livingston, Andrew Guy
Sponsor
Engineering and Physical Sciences Research Council
Grant Number
EP/M022250/1
1649713
Publisher Department
Chemical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)