Coating carboxylic and sulfate functional groups on ZrO2 nanoparticles: Antifouling enhancement of nanocomposite membranes during water treatment

This research proposes a novel method for intensifying the presence of nanoparticles on the top layer of blended nanocomposite membranes. To this end, carboxylic acid and sulfate functional groups were coated on the surface of zirconia nanoparticles. The functionalized nanoparticles were embedded in the matrix of PAN and PSf membranes, and six nanocomposite membrane models were synthesized including (ZrO2)-Zr-m@(n)PAN, (CZrO2)-C-m@(n)PAN, (SZrO2)-S-m@(n)PAN, (ZrO2)-Zr-m@(n)PSf, (CZrO2)-C-m@(n)PSf, and (SZrO2)-S-m@(n)PSf. The aim was to exploit proper arrangement of nanoparticles in the membrane matrix to strengthen the antifouling properties of the membrane. Overall, the change made in the superficial and structural properties of the membrane in response to presence of functional groups caused the internal pore blocking in (CZrO2)-C-2.68@(13)PAN and (SZrO2)-S-2.68@(13)PAN to be 50.9 and 41.8% less than that of the raw membrane, respectively. On the other hand, for the membrane lacking the functional group (ZrO2)-Zr-2.68@(13)PAN, this improvement was calculated to be only 30.9%. In terms of total fouling ratio, (CZrO2)-C-2.68@(11)PAN, (CZrO2)-C-2.68@(33)PAN, and (CZrO2)-C-2.68@(15)PAN membranes had 42.8, 39.3, and 35.6% less total filtration resistance respectively compared to the raw membrane. Considering PWF, (SZrO2)-S-2.68 @(13)PAN and (SZrO2)-S-2.68@(13)PSf had 46.2% and 52.1% more PWF than bare (13)PAN and bare (13)PSf membrane. Regarding the role of functional groups in improving the membrane separation properties, (CZrO2)-C-m@(13)PSf membranes improved dye separation percentage by 20%, compared to the raw membrane. On the other hand, (SZrO2)-S-2.68@(11)PSf membranes managed to separate 100% of Red BRLS dye due to the role of sulfate functional group in reducing the size of the membrane pores.