Polyamide Thin Films Grown on PD/SWCNT-Interlayered-PTFE Microfiltration Membranes for High-Permeance Organic Solvent Nanofiltration

Porous polymeric support membranes with outstanding organic solvent resistance are highly required for fabricating thin-film composite (TFC) organic solvent nanofiltration (OSN) membranes. In this work, we report the fabrication of a high-permeance TFC-OSN membrane by the use of a polytetrafluoroethylene (PTFE) microfiltration membrane loaded with single-walled carbon nanotubes coated by a polydopamine (PD/SWCNT) network film (named the PD/SWCNT/PTFE composite membrane) as the support. Through interfacial polymerization between m-phenylenediamine and trimesoyl chloride, a polyamide (PA) thin film has successfully grown on the surface of the PD/SWCNT/PTFE composite membrane. The resulting PA TFC-OSN membrane exhibits a high methanol permeance up to 13.2 L m–2 h–1 bar–1 with a rejection rate of 89.6% to 6-hydroxy-2-naphthalenesulfonic acid sodium salt (HNSA, Mw = 246.21). Moreover, the rejection rates of the PA TFC-OSN membrane to various dyes remain unchanged before and after DMF activation, indicating that it possesses an excellent resistance to organic solvents.