Dilute CO2 Effluents Capture Strategies with Membranes

Abstract

The increasing concentration of carbon dioxide (CO2) in the atmosphere is a significant driver of global warming and climate change, necessitating effective strategies to capture and reduce CO2 emissions, even from dilute sources. This thesis, titled "Dilute CO2 Effluents Capture Strategies with Membranes," investigates advanced membrane-based technologies for capturing CO2 from low-concentration sources (≤10%v/v CO2 ), e.g. flue gases from Biomass powerplants, residual gas of post-combustion plants, and air, to name few. Traditional carbon capture methods, such as amine-based absorption, are effective but come with significant drawbacks, including high energy consumption, increased costs, and substantial water usage. Membrane gas separation offers a promising alternative due to its process simplicity, and lower energy demands. This thesis explores the development of highly selective and permeable polymeric asymmetric membranes for capturing CO2 from low concentration sources. The membranes were synthesized by forming Pebax -MH1657 films, which were incorporated with Graphene Oxide (GO) to improve permeability and selectivity, on a macroporous support made of poly(sulfone) (PSF) using phase inversion method to provide the mechanical support necessary for the active layer to stand. Further amine functionalization to the GO was also investigated to study the impact of amine group attachment to the matrix in the performance, and two types of amines were used, Primary amine (NH3) and Polyethylenimine (PEI). Chemical, physical, and morphological analysis to investigate the nature and compatibility of produced membranes to the desired application were done. As well as Pure gas and mixed gas (low CO2 content in N2) permeance tests were performed to study the performance of the membranes by obtaining the permeance and selectivity of the membranes at different loadings of GO in the matrix. The MMMs prepared in this research were able to achieve selectivity and permeability of 52 and 23.9 GPU with the unmodified GO MMM (0.3 wt.% loading), and 54 and 25.6 GPU with the primary amine GO modified MMM for the same loading. The findings demonstrate the potential of membrane technology in efficiently capturing CO2 from dilute sources, paving the way for more sustainable and cost-effective solutions to mitigate climate change.

Date of Award	28 Jun 2024
Original language	American English
Supervisor	Ludo Dumee (Supervisor)