Effect of multicomponent fouling during microfiltration of natural surface waters containing nC₆₀ fullerene nanoparticles

To understand and mitigate the role of surface water composition and associated membrane fouling in the removal of nC₆₀ nanoparticles by low-pressure membranes, experiments were carried out with microfiltration membranes using natural feed waters, mimicking separation in real industrial water treatment plants. The effects of water composition, the presence of nanoparticles, and membrane fouling were investigated with a dead-end bench-scale system operated under constant flux conditions including a hydraulic backwash cleaning procedure. nC₆₀ nanoparticles can be efficiently removed by microfiltration and the removal efficiency is found to be independent of the water surface composition. However, the water composition controls the extent of fouling occurring during filtration. A synergistic effect on membrane fouling between nC₆₀ and surface water constituents such as natural organic matter (NOM) and its fractions is observed: the synergistic effect resulted in a transmembrane pressure (TMP) increase always higher than the sum of the TMP increase due to the filtration of nC₆₀ in ultrapure water and the TMP increase due to the surface water without nC₆₀.