Polysulfone Membranes Modified with Bioinspired Polydopamine and Silver Nanoparticles Formed in Situ To Mitigate Biofouling

The surface of a polysulfone membrane was modified with a bioinspired polydopamine (PDA) film followed by the in situ formation of silver nanoparticles (AgNPs) to mitigate membrane biofouling. The PDA modification enhanced the membrane's bacterial anti-adhesive properties by increasing the surface hydrophilicity, while AgNPs imparted strong antimicrobial properties to the membrane. The AgNPs could be generated on the membrane surface by simply exposing the membrane to AgNO3 solutions. Ag+ ions were reduced by the catechol groups in PDA; the AgNP mass loading increased with exposure time, and the AgNPs were firmly immobilized on the membrane through metal coordination. During leaching tests, the concentrations of Ag+ ions released were 2–3 orders of magnitude lower than the established contaminant limit for drinking water, thereby providing a safe antimicrobial technology. This novel membrane surface modification technique paves a way to mitigating biofouling by enhancing the membrane's anti-adhesive and antimicrobial properties, simultaneously.