Novel PVA/PEG nano-composite membranes tethered with surface engineered multi-walled carbon nanotubes for carbon dioxide separation

摘要

Cross-linked polyvinyl alcohol/polyethylene glycol membranes tethered with surface engineered multi-walled carbon nanotubes (SE-MWCNTs) were prepared and characterized by FT-IR, TGA, SEM, DMA and AFM analysis. The membranes were then analyzed for permeation testing with CO2, methane and nitrogen gases. 0.5 wt. % SE-MWCNT tethered membrane was proved to be the best performing membrane. Effect of feed gas pressure was also studied for the best performing membrane in order to check the effect of plasticization. It has been found that the gas permeation properties decrease slightly by increasing pressure up to 20 bar which is an indication that the membrane does not suffer from plasticization at high pressure. The long term stability of the best performing membrane was checked by giving it exposure to each gas at 20 bar for 96 h and taking the permeation readings after every 12 h. The best performing membrane was then tested at high pressure under mixed gas conditions (50:50) as well. Finally, the gas permeation results were plotted on 2008 Robeson plot and was found that 0.5 wt. % SE-MWCNT tethered membrane crossed the trade-off lines for both CO2/N-2 and CO2/CH4 separation under pure as well as mixed gas conditions at high pressure.