Incorporating one-dimensional aminated titania nanotubes into sulfonated poly(ether ether ketone) membrane to construct CO2-facilitated transport pathways for enhanced CO2 separation

One-dimensional aminated titania nanotubes were prepared by a facile distillation-precipitation polymerization method and were incorporated into sulfonated poly(ether ether ketone) (SPEEK) to fabricate mixed matrix membranes (MMMs). The aminated titania nanotubes (TNT-IM) with abundant amine groups increased the CO 2 -facilitated transport sites in MMMs. Moreover, the CO 2 -facilitated transport pathways (CO 2 -FTP) were constructed from aminated titania nanotubes in polymer matrix , and acted as the fast CO 2 transport channels to transfer CO 2 molecules continuously and smoothly. Water uptake and water state in MMMs also played an important role in the gas separation performance. The relationship between the water content and CO 2 separation performance was investigated. Nanotubes as fillers showed water retention properties during water evaporation from the MMMs at low humidity. The highest ideal selectivities of the SPEEK/TNT-IM MMMs for CO 2 /CH 4 and CO 2 /N 2 were 56.8 and 62.0, respectively, with a CO 2 permeability of 2090   Barrer.