Polyamide membranes with nanoscale ordered structures for fast permeation and highly selective ion-ion separation.

ABSTRACT: Fast permeation and effective solute-solute separation provide the opportunities for sustainable water treatment, but they are hindered by ineffective membranes. We present here the construction of a nanofiltration membrane with fast permeation, high rejection, and precise Cl^-/SO₄^2- separation by spatial and temporal control of interfacial polymerization via graphitic carbon nitride (g-C₃N₄). The g-C₃N₄ nanosheet binds preferentially with piperazine and tiles the water-hexane interface as revealed by molecular dynamics studies, thus lowering the diffusion rate of PIP by one order of magnitude and restricting its diffusion pathways towards the hexane phase. As a result, membranes with nanoscale ordered hollow structure are created. Transport mechanism across the structure is clarified using computational fluid dynamics simulation. Increased surface area, lower thickness, and a hollow ordered structure are identified as the key contributors to the water permeance of 105 L m²·h^-1·bar^-1 with a Na₂SO₄ rejection of 99.4% and a Cl^-/SO₄^2- selectivity of 130, which is superior to state-of-the-art NF membranes. Our approach for tuning the membrane microstructure enables the development of ultra-permeability and excellent selectivity for ion-ion separation, water purification, desalination, and organics removal.

SUBMITTER: Zhao C 

PROVIDER: S-EPMC9971196 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature