Novel thin film nanocomposite membranes developed via polydopamine nanoparticles, Halloysite nanotubes and Cu-MOF nanosheets for dye removal

High water flux and dye rejection are crucial for effective textile wastewater treatment. In this study, novel two-dimensional (2D) metal-organic frameworks (MOFs) were synthesized and combined with one-dimensional (1D) halloysite nanotubes (HNTs) and polydopamine (PDA) to fabricate the thin-film nanocomposite (TFN) membranes. The surface morphology, chemical composition, and separation performance of resultant membranes were systematically characterized to illustrate their structure-property-performance relationships. Introducing hydrophilic 1D HNTs enhanced membrane hydrophilicity and bridged large gaps between the 2D MOF nanosheets. Under optimized conditions, the PDA-HNTs/MOFs membrane achieved a water permeance of 362.1 LMH·bar⁻¹ and 99.9 % rejection of Congo Red. PDA acted as a “bridge” linking HNTs and MOFs to the membrane substrate, thereby providing excellent antifouling performance and long-term stability. After 72 h of continuous operation, this membrane maintained a 99.1 % rejection of Congo Red, greatly surpassing both pure MOFs and HNTs/MOFs membranes. These findings highlight the superior filtration capabilities and promising potential of PDA-HNTs/MOFs membranes for dye wastewater treatment.