Effect of Composite Multi-Walled Carbon Nanotube and Zeolitic Imidazolate Framework-8 on the Performance and Fouling of PVDF Membranes

The incorporation of nanoparticles into a polymer membrane has been an attractive option to minimize the membrane fouling. Polyvinylidene fluoride (PVDF) nanocomposite membranes incorporated with multi-walled carbon nanotubes (MWCNTs) and zeolitic imidazolate framework-8 (ZIF-8) was prepared in this work via the blending method. The impact of the concentration of inorganic additives (0.1 wt.%, 0.3 wt.% and 0.5 wt.%) on the membrane properties was studied. The prepared membranes were characterized using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and goniometer to investigate changes in membrane properties. Water permeability and filtration performance test were performed using pure water, bovine serum albumin (BSA) and humic acid (HA) solution to evaluate the fouling resistance of the prepared membranes. Even though the permeate fluxes decreased over time, it was found that 0.5 wt.% of ZIF-8 in PVDF membrane produced the highest solute rejection for both HA (>94%) and BSA (>92%) as compared with PVDF/MWCNT membranes and pure PVDF membrane. It is concluded that the nanocomposite membranes showed improvement in the membrane hydrophilicity, permeability, and solute rejection as compared to the pure PVDF membrane. The anti-fouling properties of nanocomposite membranes was enhanced with higher flux recovery rate and lower flux declining rate compared to the pristine PVDF membrane.