Fabrication of advanced nanofiltration membranes with nanostrand hybrid morphology mediated by ultrafast Noria–polyethyleneimine codeposition

Abstract

Polyphenol chemistry-based surface modification has received extensive attention in membrane science for its simplicity and low-cost. However, the limited molecular structures combined with the generally time-consuming process have largely restricted their further applications. Herein, we report an ultrafast and universal surface modification strategy based on the co-deposition of a macrocycle polyphenol molecule, Noria, and polyethyleneimine (PEI), for which only several seconds are required to obtain a uniform coating. Moreover, nanofiltration membranes were fabricated by traditional interfacial polymerization (IP) using the Noria–PEI co-deposited coating as the interlayer. Interestingly, the host–guest heterogeneous interaction between anchored Noria on the support surface and amine monomers in the aqueous phase could significantly alter the IP process and contribute to a unique nanostrand-hybrid morphology for piperazine and trimesoyl chloride-based membranes. Consequently, such novel morphology-based nanofiltration membranes exhibited a high permeance of up to 28 L m⁻² h⁻¹ bar⁻¹ while still maintaining comparable divalent salt (Na₂SO₄, MgSO₄, MgCl₂ and CaCl₂) rejections of above 96.0%, which are among the best performances for nanofiltration membranes. In addition to membrane science, this ultrafast surface modification strategy could arouse intense interest in host–guest chemistry at interfaces for fabricating multifunctional materials.