Covalent organic framework membrane for efficient removal of emerging trace organic contaminants from water

Emerging trace organic contaminants are harmful pollutants that accumulate over time and pose serious potential hazards to human health and the ecosystem. Membrane technology provides a promising and sustainable method to remove them from the water environment. However, the pore sizes of most commercial membranes are larger than the molecular size of most trace organic contaminants, making it challenging to achieve effective interception. Here,we propose a side-chain engineering strategy to regulate the pore size of covalent organic framework membranes from mesopore to micropore by introducing alkyl chains of varying lengths into their pore surfaces. The alkyl chain-appended covalent organic framework membranes show efficient interception of various organic pollutants, including citrate esters, nitropolycyclic aromatic hydrocarbons, organophosphate esters and pesticides as small as 0.35 nm, with a rejection rate greater than 99% and corresponding flux higher than 110 kg m−2 h−1 MPa−1. This work provides an avenue for effectively removing different types of organic pollutant from water resources to ensure the safety and sustainability of our water supply. Membranes are useful for removing pollutants from water, but the pore size of most commercial membranes is larger than the molecular size of many trace organic contaminants. Here an engineered covalent organic framework allows pore size regulation to efficiently remove organic pollutants.