Improving dye removal and antifouling performance of polysulfone nanofiltration membranes by incorporation of UiO-66 metal-organic framework

In the present work, a series of polysulfone (PSf) mixed-matrix nanofiltration membranes containing highly water stable UiO-66 metal-organic framework (MOF) were prepared via a simple phase inversion technique. At first, UiO-66 particles were synthesized via a solvothermal technique, activated via two various activation methods, including Soxhlet extraction and centrifugation methods. Then their adsorption performance was investigated for adsorption of anionic methyl orange (MO)/methyl red (MR) and cationic methylene blue (MB)/malachite green (MG) dyes from water. The activated UiO-66 particles via the Soxhlet extraction method (named S-UiO-66) showed better performance for dye adsorption with an equilibrium adsorption capacity of 15.64, 48.06, 85.48, and 93.51 mg/g for MG, MB, MO, and MR dyes, respectively. Then, the S-UiO-66 particles were incorporated into the PSf matrix in different percentages (up to 12 wt%) to prepare MMMs for dye removal from water. Separation performances of the prepared MMMs were evaluated by pure water flux, organic dye rejection, flux recovery ratio (FRR), and antifouling properties. As a result, the fabricated MMMs showed good hydrophilicity and excellent dye rejection performance. Remarkably, the pure water flux of MMM-12 with 12 wt% S-UiO-66 loading exhibited an increase of 21,495% compared to the pure PSf membrane. Additionally, the prepared MMMs showed good dye rejection and improved antifouling ability, which is attractive for large-scale industrial wastewater treatment applications.