Multi-dimensional Cooperative Channel GO/CNT/UiO-66-NH2 nanofiltration Membrane for Efficient Dye/Salt Separation

Efficient separation of organic dyes from inorganic salts in high-salinity textile wastewater remains a major challenge for resource recovery. Although graphene oxide (GO) membranes show promise for ion-sieving applications, their practical use is hindered by interlayer swelling, pore compaction, and the inherent permeability–selectivity trade-off. Here, a synergistic interlayer-engineering strategy based on a “skeleton–filler” architecture is proposed using CNT/UiO-66-NH 2 to regulate the GO/substrate interface. In this architecture, carboxylated multi-walled carbon nanotube (MWCNT-COOH) scaffolds, together with metal–organic framework (MOF) particles, effectively mask the macroporous defects of the substrate and suppress sagging of the flexible GO nanosheets. Meanwhile, the hierarchical interlayer creates low-resistance transport pathways, thereby generating a gutter effect and reducing mass-transfer resistance. Consequently, the optimized GCU-27 membrane delivers a high water permeance of 105.14 L·m ‒2 ·h ‒1 ·bar ‒1 , together with a high Congo red rejection of 99.91% and a low MgCl 2 rejection of 3.60%. As a result, a high separation factor $$ of 1071.11 is achieved. In addition, GCU-27 shows good antifouling performance ( $$ = 88.16%) and stable separation performance during 100 h of continuous operation at 70 °C. This work provides an effective interfacial-engineering strategy and mechanistic insight for the rational design of high-performance GO-based membranes for dye/salt fractionation.