Tailoring Thin-Film Nanocomposite Membrane Properties through Rational Design and Incorporation of Biomineral Nanofillers

Textile wastewater, characterized by a complex composition and high pollutant load, has become a significant global environmental challenge. Nanofiltration (NF) membranes, leveraging size exclusion and electrostatic repulsion mechanisms, can efficiently enable molecular sieving and the reuse of wastewater. Introducing an interlayer effectively optimizes the transport path of the solvent, thereby enhancing membrane permeability. This study proposes a strategy to improve NF membrane performance by depositing hydroxyapatite (HAP) nanowires as an interlayer on the substrate. HAP nanowires regulate the diffusion of amine monomers by adsorption, controlling the interfacial polymerization reaction rate and resulting in the formation of a typical Turing-structured selective layer. Moreover, the HAP nanowires significantly minimize the penetration of the selective layer into the substrate while shortening the transport path within the selective layer. Experimental results show that NF membranes with HAP intermediate layers achieve a permeation flux increase from 12.3 L·m –2 ·h –1 ·bar –1 to 22.1 L·m –2 ·h –1 ·bar –1 while maintaining excellent rejection performance. Herein, this study offers an innovative approach for designing and fabricating high-performance NF membranes and provides new insights into the application of biomaterials in separation membranes. It not only addresses technical challenges in dyeing wastewater treatment but also supports the sustainable utilization of water resources.