High-performance nanofiltration membranes enhanced by bis(4-aminophenyl) phenylphosphonate for improved thermal stability and antibacterial properties

Abstract

The increasing demands of modern industrialization underscore the need for efficient separation and purification technologies. Multifunctional nanofiltration (NF) membranes are gaining prominence as a means to lower energy consumption, enhance efficiency, and increase process flexibility. This study explores the development of thermally stable NF membranes through interfacial polymerization (IP), employing organophosphorus bis(4-aminophenyl) phenylphosphonate (BAPP) and trimesoyl chloride (TMC) as monomers in the aqueous and organic phase, respectively. The optimized BAPP-4 membrane (containing 0.1550 w/v% BAPP), which presented a nodular buried structure, exhibited exceptional water permeability (9.23 L m⁻²h⁻¹ bar ⁻¹) and high Na₂SO₄ rejection (98.52 %). Furthermore, the membrane exhibited enhanced antibacterial properties, achieving 98.00 % Escherichia coli removal, attributed to hydrogen bonding and electrostatic interactions involving amide and phosphorus groups. The BAPP-4 membrane also showed rapid flux recovery in antifouling tests, primarily due to its surface hydrophilicity. Notably, the utilization of BAPP increased the rigidity of the cross-linked polyamide network, leading to improved thermal stability. This research presents a facile and effective approach for developing high-performance and multifunctional NF membranes.