The novel Elvaloy4170/functionalized multi-walled carbon nanotubes mixed matrix membranes: Fabrication, characterization and gas separation study

This is the first report of gas transport properties of polymer Elvaloy4170. Elvaloy4170 is a commercially available polymer, which has very low price and good mechanical properties. In this work, mixed matrix membranes (MMMs) were fabricated by embedding the multi-walled carbon nanotubes (MWNTs) into Elvaloy4170. Additionally, the effects of functionalization of the nanotubes with acid treatment and their loadings were evaluated on morphology and gas permeation properties of the membranes. The fabricated membranes were characterized by Raman spectroscopy, field emission scanning electron microscopy (FESEM) and differential scanning calorimeter (DSC). Moreover, the effects of filler loading and feed pressure (from 2 to 6 bar) on CO2/CH4 transport properties were considered in pure gas experiment. The gas permeability results of Elvaloy4170 membrane revealed that with increasing the pressure from 2 to 6 bar, CO2 permeability and CO2/CH4 selectivity increased 30% and 14%, respectively. Furthermore, compared to neat membrane, the MMM with 1 wt.% of f-MWNTs increased CO2 and CH4 permeabilities by 30% and 40%, respectively. In addition, it was found that the CO2/CH4 selectivity increased as the content of f-MWNTs increased from 1 wt.% to 4 wt.% in the polymer matrix. Finally, this study reveals that membranes fabricated from commercial polymer Elvaloy4170 were permeable and have the great potential to be applied for other gas separation membrane applications. Besides, due to the considerable reactivity of the epoxide group of Elvaloy4170, it tends to take part in chemical reactions and form covalent bond with functionalized groups to construct more efficient MMMs.