Nanoparticle-templated nanofiltration membranes for ultrahigh performance desalination

TLDR

Nanofiltration membranes with high permeance and rejection are essential for efficient desalination, yet improving permeance while maintaining rejection remains a challenge. This study aims to fabricate a thin‑film composite nanofiltration membrane with a crumpled polyamide layer using nanoparticle templating. The membrane is produced by interfacial polymerization on a single‑walled carbon nanotube/polyether sulfone support loaded with ZIF‑8 nanoparticles that are later dissolved, creating a rough, crumpled polyamide active layer. The resulting membrane achieves 53.5 l m⁻² h⁻¹ bar⁻¹ permeance with >95 % Na₂SO₄ rejection, outperforming state‑of‑the‑art nanofiltration membranes.

Abstract

Abstract Nanofiltration (NF) membranes with ultrahigh permeance and high rejection are highly beneficial for efficient desalination and wastewater treatment. Improving water permeance while maintaining the high rejection of state-of-the-art thin film composite (TFC) NF membranes remains a great challenge. Herein, we report the fabrication of a TFC NF membrane with a crumpled polyamide (PA) layer via interfacial polymerization on a single-walled carbon nanotubes/polyether sulfone composite support loaded with nanoparticles as a sacrificial templating material, using metal-organic framework nanoparticles (ZIF-8) as an example. The nanoparticles, which can be removed by water dissolution after interfacial polymerization, facilitate the formation of a rough PA active layer with crumpled nanostructure. The NF membrane obtained thereby exhibits high permeance up to 53.5 l m −2 h −1 bar −1 with a rejection above 95% for Na 2 SO 4 , yielding an overall desalination performance superior to state-of-the-art NF membranes reported so far. Our work provides a simple avenue to fabricate advanced PA NF membranes with outstanding performance.