Carboxymethyl chitosan/carbon nanotubes mixed matrix membranes for CO2 separation

The separation of CO2 using membranes has grabbed vast attention of researchers in the recent years. In this study, a thermally stable carboxymethyl chitosan (CMC)/multiwalled carbon nanotubes (CNTs) mixed matrix membrane (MMM) has been proposed for separation of CO2 from CO2/N2 gas mixture. Herein, the amine groups present in CMC serve as CO2 carrier and CNTs provide alternate pathway to the gas molecules. Various spectroscopic and microscopic analyses have been performed to confirm the successful wrapping of CNTs. Further, the prepared mixed matrix membranes were characterized using field emission scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and dynamic mechanical analyzer. The wrapping of CNT improves the dispersion of CNT in CMC matrix. The moisture holding ability of the membranes which is essential for the facilitated transport reaction has been measured at different humid conditions. The CMC/CNTs MMM exhibited CO2 permeance and CO2/N2 selectivity of 43 GPU and 45, respectively, at sweep/feed water supply ratio of 3 and at 80 °C temperature.