Durable TiO2@Cu-alginate hydrogel membrane with rapid in-situ cleaning for high-performance dye desalination applications

Abstract

Nanofiltration (NF) membrane filtration has garnered significant attention for the desalination of high-value-added molecules due to its exceptional selective separation performance. In this study, CuCaAlg/TiO₂ membranes were synthesized by physically incorporating nanoparticles into the natural alginate polymer network through dual cross-linking. The synthesis process was rapid, straightforward, and environmentally friendly, with no organic waste discharge. The interaction between rigid inorganic nanofillers and polymer networks not only enhances the mechanical strength of the hydrogel but also modulates the degree of topological defects within the membrane structure. This modulation facilitates overcoming the selective separation-permeation trade-off effect in the separation process. The resulting membrane exhibited outstanding dye/salt separation performance, including high permeability and efficient dye/salt selectivity separation. Additionally, the membrane demonstrated excellent hydrophilicity, swelling resistance, and anti-fouling properties. Furthermore, combined with a simple cleaning strategy (UV-H₂O₂-cross flow filtration), this composite functional membrane enabled rapid in-situ cleaning in high-concentration dye application scenarios. Such cleaning procedures contribute to maintaining the stability of the hydrogel membrane during dye desalination and separation applications. We anticipate that this composite membrane holds great promise for resource treatment of dye wastewater across various scenarios.