Thermal-facilitated interfacial polymerization toward high-performance polyester desalination membrane

Abstract

Polyester thin film composite (PE-TFC) membranes featuring excellent chlorine-resistant property hold grand promise in seawater desalination and wastewater treatment. However, the low reactivity of alcohol or phenolic hydroxyl groups with acyl chloride groups usually leads to the formation of a relatively loose PE network, resulting in undesirable salt rejection. Preparing high-performance PE-TFC membranes remains a daunting challenge. In this study, we propose a thermal-facilitated interfacial polymerization (TFIP) approach to fabricate PE-TFC membranes with high desalination performance. The elevated temperature promoted the diffusion of glucose monomers across the water/heptane interface and then facilitated the reaction rate between glucose and TMC during interfacial polymerization (IP), resulting in the formation of PE layer with a higher cross-linking density compared to that fabricated via conventional IP. The PE membrane prepared via TFIP exhibited a superior ion rejection of 99.5% for Na₂SO₄ and high water permeance up to 16.1 L m⁻² h⁻¹ bar⁻¹, outperforming all the polyester membranes with similar rejection in literature. The resultant PE-TFC membrane displayed unprecedented chlorine resistance (960 000 ppm h) and maintained separation efficiency after exposed to sodium hypochlorite solution (1000 ppm) for 36 days. Polyols including sucrose, raffinose and β-CD were also utilized as monomers, confirming the universality of the TFIP approach for facile preparation of high-performance desalination membranes.