A new antifouling metal-organic framework based UF membrane for oil-water separation: A comparative study on the effect of MOF (UiO-66-NH2) ligand modification

Surface-modified metal-organic frameworks (MOFs) were used for the fabrication of polyethersulfone (PES)-based polymeric composite membranes by phase inversion method. Initially, zirconium-based MOF, UiO-66-NH2, was modified with melamine (denoted as UiO-66-NH-Mlm) and ethylenediamine (UiO-66-NH-EtNH2) via a solvothermal post-modification technique. The fabricated polymeric membranes were then employed for oil-water separation and showed satisfactory hydrophilicity and antifouling performance (PWF: 55.38 kg/m(2)center dot h, FRR: 90.67 %, Rr: 46.94%, Rir: 9.33% and >99% rejection to the oil). It was due to the formation of the hydration layer, arising from the available -NH2 groups (providing hydrogen-bonding) on the surface of the modified MOFs (WCA: 51.66 degrees), and the lower surface roughness. Higher hydrophilicity and better antifouling efficiency were obtained for the membranes using UiO-66-NH-Mlm, compared to UiO-66-NH-EtNH2, due to the higher number of -NH2 groups. The membranes also exhibited good thermal stability owing to the fine dispersion of the modified MOFs in the polymeric texture and the presence of metallic cores in the MOFs. The membranes were also applied for frequent filtrations with great performance.

Automated summary

Surface-modified metal-organic frameworks were used to fabricate polyethersulfone-based polymeric composite membranes with satisfactory hydrophilicity and antifouling performance for oil-water separation and frequent filtrations.