Facile fabrication of COF-LZU1/PES composite membrane via interfacial polymerization on microfiltration substrate for dye/salt separation

Covalent organic frameworks (COFs) have attracted great interest as advanced membrane materials due to their uniform channel structure and high porosity. In this work, COF-LZU1/PES composite membranes were prepared via interfacial polymerization (IP) process, and the thin and defectless COFs active layers were successfully grown on poly (ether sulfone) (PES) microfiltration substrates with 1,3,5-triformylbenzene (TFB) and p-phenylenediamine (PDA) as precursors. The prepared COF-LZU1/PES composite membranes exhibit a high rejection rate (>99.0%) for the dyes with molecular size above 1.5 nm and nonselective permeation for inorganic salts (<12.0%). At the same time, a water permeance above 80.0 L m(-2) h(-1).bar(-1) is achieved, which is much higher than many other membranes with similar rejections. Long-term filtration demonstrates that COF-LZU1/PES membranes have good water stability. The excellent water permeance, high dyes separation performance and great stability endow COF-LZU1/PES membranes the performance of removing dyes from saline wastewater.

Automated summary

Covalent organic frameworks (COFs) have been researched for their advanced membrane materials potential due to their uniform channel structure and high porosity. COF-LZU1/PES composite membranes prepared via interfacial polymerization (IP) process exhibit high rejection rates (>99.0%) for dyes, with nonselective permeation for inorganic salts (<12.0%) and a water permeance above 80.0 L m(-2) h(-1).bar(-1). The membranes show good water stability and are effective for removing dyes from saline wastewater.