Thermostable nanofiltration membranes enabling superior hot wastewater purification

Abstract

Emerging nanofiltration (NF) separation technology for precision ionic/molecular separation at the nanoscale, which has the advantages of energy conservation, excellent separation and a small footprint, is promising for obtaining sustainable water resources via efficient water treatment and recycling. However, traditional NF membranes are restricted to applications at approximately room temperature because of the sharp deterioration in stability induced by the fragility of the nanopore structure at higher temperatures. Herein, we synthesized an unparalleled nanofiltration (NF) membrane with superior thermal stability up to 90 °C and finely tailored nanopores with 0.3–1.1 nm, via de novo carbon skeleton-mediated polymerization (CSMP). Molecular thermodynamics simulations and experiments demonstrated that C–C skeletons can manipulate the stability of the intrinsic structure and intermolecular gap size, contributing to exceptionally thermostable and well-tailored nanopores. The synthesized membrane exhibited excellent long-term water permeance and high rejection of (sub)nanoscale contaminant molecules at high temperatures, which is far superior to the performance of currently available NF membranes.