Porous vermiculite membrane with high permeance for carbon capture

Two-dimensional (2D) membranes with interlayer nanochannels hold great promise for CO 2 capture. However, the permeance is often limited by the high transmembrane resistance primarily caused by the tortuous interlayer diffusion pathway. Here, a facile method for preparing 2D porous vermiculite (PVMT) membranes is presented to boost CO 2 transport by increasing the number of additional through-plane channels. The pristine vermiculite (VMT) nanosheets were treated with acid etching to generate nanopores by dissolving metal cations thereon. The resulting porous nanosheets were co-assembled with polyethyleneimine (PEI) molecules by vacuum-assisted self-assembly to fabricate PVMT-PEI membranes. The PEI molecules regulate the channel size to elevate the diffusion of CO 2 and their amino groups afford affinity toward CO 2 to increase its dissolution, thus intensifying the facilitated transport mechanism. The optimized PVMT-PEI membrane shows high performance with CO 2 permeance of 568 GPU and CO 2 /CH 4 selectivity of 27.6, which is 165% and 94% higher than pristine VMT membrane. In addition, the PVMT-PEI membranes exhibit good long-term operation stability.