Preparation of dioxime-modified sodium alginate/MXene composite membrane with different carbon chain backbone and study on separation performance for organic dyes and oily wastewater

To regulate the interlayer spacing, composite membranes with distinct spatial structures were prepared by modifying sodium alginate using three hydrazides with varying carbon chain lengths (AAD, TPDH, and BDD). The layered MXene nanosheets were crosslinked with KH550, and hydrophilic-oleophobic composite membranes were fabricated on PVDF substrates. The membrane prepared with 0.2 vol% KH550 exhibited optimal pollutant rejection performance, achieving >99 % rejection rates for Congo Red (CR) and oil-in-water emulsions, and >96 % for Methylene Blue (MB). Among these, DSA-AAD/MXene featured the smallest interlayer spacing and the lowest pure water flux (957.96 L m -2 h −1 ). Furthermore, the study systematically investigated the effects of pH, salt ion concentration, and suspended substances on membrane performance, demonstrating excellent resistance to acids, alkalis, fouling, and salts. This work underscores the significant potential of novel MXene-based membranes for efficient dye/mixture separation in the textile industry, offering a promising strategy for developing high-performance separation membranes.