Sustainable Co2 Capture by Constructing Poly (Vinyl Alcohol)/Polyethyleneimine Facilitated Transport Barrier on Commercial Polyamide Membrane Platform

Abstract

Facilitated transport membranes (FTMs) have been widely acknowledged to overcome the trade-off limit between permeability and selectivity in CO2 separation membranes. Until now, most CO2-FTMs still face challenges in industrial application due to the expensive manufacturing cost and insufficient stability. In this work, a cost-effective method was proposed to prepare permeable and sustainable CO2-FTMs through direct surface construction of poly (vinyl alcohol) (PVA) and polyethyleneimine (PEI) composite barriers on commercial polyamide membrane platforms. As a crucial improvement, PVA was introduced to provide double functions. Firstly, it significantly increases the loading density of PEI carriers on membrane surface by almost 6 times due to its excellent affinity to both PEI and PA matrix. Secondly, PVA integration made membrane hydrophilic enough to maintain a moist state, ensuring the sustainability of CO2 transport with a constant operation over 70 hours compared to 10 hours when using PEI alone. SEM, XPS and FTIR measurements were employed to determine the adsorption and distribution of PEI and PVA on membrane surface. A satisfactory CO2 permeability (102 GPU) and CO2/N2 selectivity (92.7) were achieved at an optimum modification condition. This PVA enhanced CO2-FTM developed in this work has great potential in large-scale CO2 capture.

Keywords: CO2 facilitated transport, Surface construction, Polyvinyl alcohol, Polyethyleneimine, Polyamide membrane