Facile fabrication of ceramic-based highly permeable composite nanofiltration membranes by in-situ interfacial polymerization

The preparation of thin-film composite (TFC) membranes with both extraordinary permeance and excellent rejection performance are still a challenge due to the irreversible and rapid interfacial polymerization (IP). The high reactivity of amine monomers helps to form a defect-free membrane instantaneously during the IP process, but also ultimately leads to low water permeance. Here, a facile strategy was proposed to improve the performance of TFC membrane by conducting in-situ IP on the nanoporous ceramic membranes. First, it was confirmed that the hydrophilic ceramic membrane, which serves as an oil-water interface, can provide a uniform aqueous layer. The free-like interface is conductive to the formation of defect less polyamide layer even at ultra-low monomer concentrations and very short reaction times. Then, the performance of TFC membranes using ceramic membranes with different pore sizes as supports was systematically investigated. The result indicates that supports with smaller pore size and narrower distribution enable facilitate the formation of a thinner membrane. Moreover, the nanofiltration membrane exhibited ultra-high pure water permeances of 42.9 LMH/bar and a rejection of 93.4 % to Na₂SO₄, utilizing a ceramic membrane with a pore size of 10 nm as support under PIP of 0.025 wt% and reaction times of 10 s.