Antifouling polyethersulfone composite ultrafiltration membrane fabricated with SiO2-g-PAA as additive and its application in oil-in-water emulsion

In order to reduce silica nanoparticles (SiO 2 NPs) agglomeration, improve the dispersity of SiO 2 NPs in the matrix of polyethersulfone (PES) composite membrane, the poly (acrylic acid) grafted SiO 2 NPs (SiO 2 -g-PAA NPs) are beforehand synthesized via surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). PES/SiO 2 -g-PAA organic-inorganic composite membranes are convenient fabricated by blending PES matrix with the as-synthesized SiO 2 -g-PAA NPs via the non-solvent induced phase separation (NIPS) process. The attenuated total reflectance Fourier-transform infrared spectroscopy and surface scanning electron microscope (SEM) results confirm that the well dispersed SiO 2 -g-PAA NPs tend to migrate toward the membrane top surfaces. As a result, the composite membrane exhibited the highest pure water flux and oil flux around 233.72 and 97.29 L/m 2 h, which equal to 3.6 times and 8.8 times of unmodified PES membrane respectively. The flux recovery rate increased from 45.74% to 77.12%, suggesting the fouling-resistance of the composite membranes was greatly improved. Furthermore, the SiO 2 -g-PAA NPs exhibit excellent stability in the membrane matrix benefit from the interaction between PAA polymer chains and PES. In addition, the reactive PAA chains on the membrane surface provide a platform for further functionalization.