PrestructuredMXenefillers with uniform channels to enhanceCO₂selective permeation in mixed matrix membranes

Abstract

The packing pattern of two-dimensional (2D) sheet-like fillers in membranes is relatively random, leading to the unfavorable permeability from tortuous diffusion pathway. A new strategy that using prestructured materials with uniform channels as fillers was proposed. In this work, Ti 3 AlC 2 is etched to prepare multilayered MXene (m-MXene), the channels aggregate as a whole unit, ensure the impossibility of ineffective packing compared with traditional individual sheets, largely facilitating the selective permeation. Then, the m-MXene/Poly (amide-6-b-ethylene oxide) (Pebax) MMMs are synthesized. SEM images demonstrate the accordion shaped structure of filler, which is the multi-channels laminates. Furthermore, the results of gas permeation test exhibit enhanced performance of m-MXene/Pebax MMMs. MMM with 0.5 wt.% m-MXene behaved best, CO 2 permeability of 86.22 Barrer as well as CO 2 /N 2 selectivity of 104.85, transcending the Robeson upper bound (2008). Having distinct enhancement for CO 2 separation, the m-MXene/Pebax MMMs in this work offer prospective practical applications. K E Y W O R D S CO 2 separation, Pebax, Mixed matrix membranes and MXene Weixin Guan and Xiaochen Yang contributed equally to this work

Preparation ofAl2O3/PDA/Pebax membrane modified by (C3NH2MIm)(PF6) for improvingCO2separation performance

“…This was mainly caused by two factors. On the one hand, the wrinkle phenomenon caused by the stacking of the chain segments during the evaporation of the solvent for preparing the membrane 45 . On the other hand, more Al 2 O 3 /PDA‐TIL nanosized particles were exposed due to the interaction between the particles and the Pebax segment with the increase of Al 2 O 3 /PDA‐TIL loadings 46 .…”

“…82,83 However, these factors mentioned above have no effect on N 2 . What is more, due to the Al 2 O 3 /PDA-TIL fillers overlapping in a limited space, the partial pore-blocking effect was more serious, 84 so that the permeability of larger molecules N 2 decreased with the increase of Al 2 O 3 /PDA-TIL in MMMs. Therefore, CO 2 /N 2 selectivity was significantly improved.…”

Fabrication of Pebax/SAPO mixed matrix membranes for CO2/N2 separation

“…The increased permeability is ascribed to the improvement of proportion of permeable amorphous phase, interfacial microvoids in membrane matrix as well as the porosity of zeolite 44,48 . However, the adverse effects of pore‐blocking and tortuosity‐prolonging of diffusion path would be more serious due to the overlapping and agglomeration of fillers at high‐loading amount 14,49 . Anyhow, the handsome selectivity proves the good compatibility of adopted SAPO zeolite with Pebax‐1074.…”

MXene‐Based Membranes for Separation Applications

“…[35] More recently, the permeance of CO 2 and the selectivity of CO 2 /N 2 gas pair both have been greatly improved by Guan et al, given that the resulting permeability of CO 2 was %86 Barrer and the CO 2 / N 2 selectivity was over 104. [36]…”