Chemical Engineering Journal Advances 18 (2024) 100601 Available online 18 March 2024 2666-8211/© 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by- nc/4.0/). Carbon dioxide absorption in a gas-liquid membrane contactor: Infuence of membrane properties and absorbent chemistry Nomcebo P. Khumalo, Bhekie B. Mamba, Mxolisi M. Motsa * Institute for Nanotechnology and Water Sustainability (iNanoWS), College of Science, Engineering, and Technology, University of South Africa, Science Campus, Florida 1709, Johannesburg, South Africa A R T I C L E INFO Keywords: Hollow fbre membranes Hydrophobicity Gas liquid membrane contactor Carbon dioxide absorption ABSTRACT The present work demonstrates the performance of hollow fbre membranes fabricated using polyvinyl chloride, polystyrene (EPS) and polydimethylsiloxane (PDMS) coupled with 30% monoethanolamine (MEA) in a gas liquid membrane contactor (GLMC) for the absorption of carbon dioxide. A gas mixture with a composition of (50/50 v/v%) methane (CH 4 ) and (CO 2 ) was used to assess the effciency of the prepared membranes in the removal of carbon dioxide. Then HFM 3 which showed high CO 2 removal was used to separate a mixture of nitrogen (N 2 )/ oxygen(O 2 )/carbon dioxide (CO 2 ) with a composition of (73/18/9 v/v%), respectively. Four different absorption liquids: 30 % MEA solution, 30 % EDA solution, 30 % MEA – graphene oxide (GO) and 30 % EDA-GO nanofuids were coupled with HFM3 to analyse the effciency of the different amine liquids in CO 2 absorption in GLMC. The 30 % EDA-GO solution showed an increase in the effciency of CO 2 absorption. The nanofuids showed an enhancement factor for CO 2 absorption in the nanofuid was 121 % and 117 % for MEA-GO and EDA-GO, respectively. This enhancement was attributed to the hydrodynamic effects and Brownian motion of graphene oxide in the amine liquids. 30 % EDA solution infused with 0.2 mg/ml graphene oxide nanoparticles achieved the highest loading of carbon dioxide 0.25 mol/ cm 3 . 1. Introduction Carbon dioxide gas emissions into the atmosphere from industrial activities such as electricity generation in coal-fred power plants, nat- ural gas production, petroleum refning processes, etc., are of great concern due to their contribution to global warming and, subsequently, climate change [1]. Therefore, carbon dioxide capture and storage (CCS) has been recommended by the Intergovernmental Panel on Climate Change (IPCC) as a mitigation strategy to reduce CO 2 concentrations in the atmosphere. Implementing CCS in carbon dioxide emitting processes can reduce its emissions into the atmosphere by 14 to 17 % [2]. Con- ventional technology widely used in industries to absorb CO 2 is based on chemical absorption, where CO 2 is absorbed by amine liquids [3]. Monoethanolamine (MEA) is currently the most widely used amine-based absorption liquid during CO 2 absorption in industrial practices due to its high reaction rate [4]. However, in order to advance technology, researchers have introduced ionic liquids as an environ- mentally friendly option for CO 2 absorption [5–7]. Benign absorption liquids, such as ionic liquids, have lower carbon dioxide absorption capacities due to the slow hydration kinetics of CO2 [8]. The introduction of nanoparticles in absorbents to increase the absorption rate has also been investigated by several studies to enhance CO 2 ab- sorption [9–11]. Recently, research on gas-liquid membrane contactors has gained traction in the purifcation and separation of gases. A gas liquid mem- brane contractor is a gas separation/purifcation technique that in- tegrates membrane technology and chemical absorption [12–14]. The role of the microporous membrane is to create a barrier between the two fowing streams, while permeating the gas into the liquid stream to allow increased contact area, thus increasing CO 2 absorption [15]. The presence of an absorption liquid eliminates the dependence on the membrane for selectivity because the liquid provides high affnity to carbon dioxide. During carbon dioxide absorption, CO 2 permeates into the liquid stream, whereby the absorption liquid (amine, ionic/nano- fuid) absorbs the permeated gas. Hollow fbre membranes have a high surface contact area when densely packed in a GLMC module [16,17]. Therefore, the gas liquid membrane contactor technique boasts of a high surface area to low volume ratio, compact size with high selectivity and independent control of fow rates for the liquid and gas streams, as well as ease of down/up scaling to retroft at desired processes [14,18]. * Corresponding author. E-mail address: motsamm@unisa.ac.za (M.M. Motsa). Contents lists available at ScienceDirect Chemical Engineering Journal Advances journal homepage: www.sciencedirect.com/journal/chemical-engineering-journal-advances https://doi.org/10.1016/j.ceja.2024.100601