Ethylene vinyl acetate copolymer/Mg-Al-layered double hydroxide nanocomposite membranes applied in CO2/N2 gas separation

Series of ethylene vinyl acetate (EVA) copolymer/layered double hydroxide (LDH) nanocomposite membranes with 40 wt% vinyl acetate content (EVA/12AA-LDH) were prepared by solution blending and casting, and applied in membrane gas separation. The organically modification of LDH nanolayers (12AA-LDH) was manufactured by using 12-aminododecanoic acid (12AA) as an intercalation agent via co-precipitation method. The distance between the 12AA-LDH nanolayers was approximately 2.10 nm from calculation of the XRD diffraction pattern, which resulted from the successful intercalation of 12AA within the LDH. The result of CO2 adsorption isotherms shows that 12AA-LDH is much more attractive than the neat LDH, which enhances the performance in membrane separation. Furthermore, the exfoliated/intercalated morphology of 12AA-LDH/LDH structures within EVA matrix was prepared successfully and can be observed clearly by transmission electron microscopy micrographs. The gas permeation performance of the EVA/12AA-LDH nanocomposite membranes was measured, and the results show that the best selectivity of CO2/N-2 increased to 20 with a CO2 permeability of 119.21 barrer for the composite membrane containing 1.0 wt% 12AA-LDH. This result not only attributed to the exfoliation of the 12AA-LDH nanolayers within the EVA matrix, but also the amino group of 12AA interacted more with CO2 compared with N-2 and O-2. This result illustrated that 12AA-LDH shows highly potential for use as an additive in CO2 capture membranes.

Automated summary

By synthesizing and characterizing nanocomposite membranes of ethylene vinyl acetate (EVA) and layered double hydroxide (LDH), it was found that 12AA-LDH has better adsorption performance for CO2 than neat LDH, enhancing membrane separation performance. Additionally, 12AA-LDH shows high potential for use as an additive in CO2 capture membranes.