Ultrafast seawater desalination with covalent organic framework membranes

The lack of access to clean water for billions of people represents a fundamental global sustainability challenge that must be addressed. Seawater desalination using membrane technologies provides a promising solution; however, the dominating desalination membranes often show low permeation flux and deficient fouling resistance. Here we achieve ultrafast desalination by taking advantage of covalent organic framework (COF) membranes where TaPa-SO3H nanosheets are linked by TpTTPA nanoribbons through electrostatic and pi-pi interactions to form an ordered and robust structure. The optimum COF membrane exhibits excellent rejection of NaCl (99.91%) and more importantly an ultrafast water flux of 267 kg m(-2) h(-1), which outperforms the state-of-the-art designs and is 4-10 times higher than conventional membranes. Furthermore, the desired fouling resistance underpins superior operational stability (108 h) and high salinity (7.5 wt%) tolerance, offering great potential in practical applications.

Automated summary

The lack of access to clean water for billions of people is a global sustainability challenge, which can be addressed by membrane technologies. The use of covalent organic framework (COF) membranes can achieve ultrafast desalination and excellent fouling resistance, offering great potential in practical applications.