Building high-performance mixed matrix membranes from stable COF colloids for CO 2 /N 2 separation

A "retardation & solvation" strategy was developed for synthesizing stable β-ketoenamine-linked covalent organic framework (COF) colloids. Their mixed matrix membranes (MMMs) with a Pebax-1657 matrix exhibited exceptional gas separation performance with a CO₂ permeability up to 322 Barrer and a CO₂/N₂ selectivity over 72.1. These represent improvements of 4.25 and 1.49-fold over the pristine Pebax-1657 membrane under identical conditions, closely approaching the 2019 Robeson upper boundary.