Enhanced nanofiltration performance of thin film nanocomposite membranes incorporating polydopamine modified UiO-66 for water treatment

In recent years, metal–organic frameworks (MOFs) have proven to be effective nanofillers for fabricating thin-film nanocomposite (TFN) membranes for dye wastewater treatment. In this study, University of Oslo-66 (UiO-66) was modified with polydopamine (PDA) to synthesize PDA@UiO-66 nanoparticles, aiming to overcome their inherent dispersion and compatibility limitations. Subsequently, TFN membranes incorporating PDA@UiO-66 (denoted as TFN-PDU) were fabricated via interfacial polymerization using an aqueous piperazine (PIP) solution containing well-dispersed PDA@UiO-66 and an organic trimesoyl chloride (TMC) solution. Owing to the suitable pore size, improved hydrophilicity, and enhanced compatibility of PDA@UiO-66, the prepared TFN-PDU membranes exhibited elevated water permeability, salt rejection, and dye desalination performance compared to the pristine thin-film composite (TFC) membrane and the TFN membrane containing unmodified UiO-66. The effects of different PDA@UiO-66 loadings on membrane morphology, structure, and performance were systematically investigated. Compared to the conventional UiO-66-incorporated TFN membrane (water permeability: 5.21 L·m −2 ·h −1 ·bar −1 ), the optimal TFN-PDU2 membrane (with 0.10 wt% PDA@UiO-66 loading) exhibited a higher water permeability of 6.85 L·m −2 ·h −1 ·bar −1 , an increased Na 2 SO 4 rejection (from 87.6% to 89.4%), and an enhanced methylene blue (MB) rejection (from 93.4% to 95.6%). This study provides a feasible strategy for designing high-performance TFN membranes using hydrophilic MOFs for efficient dye wastewater treatment.