Tailoring high-performance polyesteramide NF membranes for purifying natural surface water: Enhanced minerals preservation, chlorine resistance, and mechanisms

Abstract

Nanofiltration membranes (NF) possessing high flux, excellent selectivity, and chlorine resistance are urgently required for healthy drinking water treatment. In this work, we prepared a high-performance polyesteramide (PEA) nanofiltration membrane featuring polyester and polyamide composite structures using piperazine (PIP) and polyvinyl alcohol (PVA) as co-monomers via sodium hydroxide catalyzing interfacial polymerization. The resultant NF membranes' surface morphology, chemical structure, filtration performance, and chlorine stability were systematically evaluated. The optimized PEA membrane (PEA-TFC) possessed a terraced morphology and relatively high roughness (23.9 nm). During purifying real surface water, a high flux (20.29 LMH bar⁻¹) with <50 % mineral rejection and over 70 % organic matter removal was achieved for PEA-TFC, demonstrating excellent organic/mineral selectivity. In addition, the polyamide and polyester structures provided uniform pore size distribution and fewer chlorine-active sites, granting PEA-TFC excellent chlorine resistance and stability. The exceptional organic/mineral selective separations and remarkable chlorine resistance endow the PEA-TFC as a promising candidate for healthy drinking water NF.