Research on the modification of thin-film composite membrane by silica nanoparticles and antifouling performance

In this study, we developed a facile strategy to modify a forward osmosis thin-film composite (TFC) membrane via surface grafting of silica nanoparticles (SiNPs), which was functionalized with amine moieties (3-Aminopropyl trimethoxysilane, APTMS). The APTMS functionalized SiNPs were grafted on the negatively charged TFC membrane via electrostatic interactions during a dip-coating process, to enhance membrane hydrophilicity and impart fouling resistance. After modification process, dense nanoparticles were found grafted on membrane surface. Compared to the pristine membrane, contact angle of the modified membranes significantly reduced by 54%, while surface zeta potential and roughness presented negligible changes. For dynamic fouling tests using sodium alginate as a model foulant, flux behavior and fouling layer characterizations revealed that the modified membranes exhibited notably fouling resistance than the pristine membrane during later period, with flux decline remarkably reduced by 28% and deposited foulants decreased by 35%. The antifouling property of the membrane was mainly attributed to substantial hydrophilicity enhancement due to APTMS-SiNPs functionalization. © 2020, Editorial Board of China Environmental Science. All right reserved.