Graphene Oxide Nanofiltration Membranes for Desalination at Realistic Conditions

A new generation of nanofiltration membranes is essential to address the rapidly increasing difficulties in sustainable production and recycle of industrial water. Graphene oxide (GO)-based membranes have shown potential to revolutionize nanofiltration, but sustaining solute rejections at realistic concentrations has been a main challenge. We show that a series of membranes consisting of GO bound with polycyclic π-conjugated cations display dramatically enhanced rejections for salts and neutral solutes over a wide concentration range. Furthermore, we find that the counter-intuitive solute rejection behaviors observed in these π-intercalated GO membranes can be explained by a dual mechanism of interlayer spacing modulation and creation of diffusion barriers in the two dimensional interlayer galleries. These membranes are easily scalable, and display high chemical and mechanical robustness in desalination of a multicomponent industrial stream at elevated pH, temperature, stream velocity, and solids content.