Exfoliation-free layered double hydroxides laminates intercalated with amino acids for enhanced CO2 separation of mixed matrix membrane

Harvesting energy from biogas is a potential way to retard the depletion of fossil fuels and fight against global warming simultaneously. Membrane technology holds great promise to achieve cost-effective biogas upgrading, along with advantages of low energy consumption and environmental friendliness, which leads to extensive exploration in fabricating CO 2 membranes with high separation performance. In this study, mixed matrix membranes are fabricated by incorporating exfoliation-free layered double hydroxides laminates intercalated with amino acids (Phe with hydrophobic side chains and Glu with hydrophilic side chains) into a low-cost commercial Pebax (poly (amide-b-ethylene oxide)) polymer. Both amino and carboxyl groups can facilitate the transport of CO 2 through quadrupole moment interaction, enlarged interlayer spacing and reversible reaction. Particularly, MMM containing 5 wt% AA-LDH exhibits an optimal permeability of 790 Barrer and a promising CO 2 /CH 4 selectivity of 31, which is 64.6% and 83.9% higher than the pristine Pebax membrane, respectively. The distinct advantages in terms of facile fabrication and processability confer the LDH-based membrane with great potential for large-scale CO 2 capture and separation.