Abstract
Achieving a balance between flux and rejection remains a key challenge in nanofiltration membrane design for water treatment. In this study, a bimodal inorganic UiO-66 nanocomposite membrane was fabricated using an ex-situ deposition method and evaluated for filtering organic contaminants from water. Polydispersed UiO-66 nanoparticles (14 and 108 nm) were synthesized by modulating water content (0.2–2.0 mL) during synthesis. Characterization via XRD, TEM, FTIR, and TGA confirmed the structure and distribution of UiO-66. XRD results showed characteristic peaks at 2θ = 7.34° and 8.48°, indicating the formation of a face-centered cubic crystal structure. Peak broadening at 2θ = 8.6° and 10° was observed with increased water addition. TEM analysis revealed the impact of water modulation on nanoparticle size. Unimodal UiO-66 suspensions (14 and 108 nm) were deposited on a microfiltration regenerated cellulose (RC) support via suction filtration (900 mbar, 30 min), forming a bimodal membrane. After partial drying, the membranes were tested for methylene blue rejection. At 99% rejection and 900 mbar pressure, the bimodal UiO-66 membrane achieved a high water permeability of 400 ± 5.33 L/m²/h. These results demonstrate the potential of ex-situ synthesized bimodal UiO-66 membranes for efficient nanofiltration in water treatment.