Boehmite nanoparticles as a new nanofiller for preparation of antifouling mixed matrix membranes

The influences of boehmite nanoparticles as innovative nanofiller on fabrication of polyethersulfone (PES) blended membranes were investigated in terms of hydrophilicity, permeation performance, membrane morphology and antifouling property. Boehmite is an aluminum oxide hydroxide (γ-AlOOH) particle, containing extra hydroxyl groups on its surface. The hydrophilicity and pure water flux of the membranes were improved by incorporating of boehmite nanoparticles. Scanning electron microscopic (SEM) images showed that the nanoboehmite embedded membranes possessed a typical asymmetric structure similar with the bare PES membrane. In other words, embedding of the nanoboehmite did not change the finger-like structure of the membranes. Moreover, the high resolution SEM images revealed agglomeration of the nanoparticles at high concentrations. This reduced the pure water flux and increased the membrane resistances. The whey filtration results indicated that by addition of the low quantity of nanoboehmite, the fouling resistance parameters were significantly declined due to lower roughness and higher hydrophilicity of the surface of the modified membranes. These changes in the membrane characteristics improved the flux recovery ratio (FRR). Comparison of the nanoboehmite embedded membranes with the γ-Al2O3/PES membranes demonstrated superior characteristics and antifouling properties of the nanoboehmite mixed matrix membrane. The 1 wt.% nanoboehmite/PES membrane exhibited the highest FRR value of 96.1% and the lowest irreversible fouling resistance (Rir) value of 3.9%.

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► Effect of mixing nanoboehmite on fouling mitigation of PES membrane was examined.
► Extra hydroxyl groups of nanoboehmite improved hydrophilicity of blend membranes.
► SEM images revealed agglomeration of the nanoparticles at high concentrations.
► Addition of low quantity of nanoboehmite decreased fouling resistance parameters.
► Effect of surface roughness in fouling mitigation was higher than hydrophilicity.