Improvement of antibiofouling performance of a reverse osmosis membrane through biocide release and adhesion resistance

To improve antibiofouling properties, a commercial reverse osmosis (RO) membrane was modified by surface deposition of a polyelectrolyte multilayers (PEMs) embedded with silver nanoparticles. The modified membrane was further coated with an amphiphilic polyzwitterion, a 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymer with 2-aminoethyl methacrylate (AEMA). Thus, the modified surface layer consisted of PEMs embedded with silver nanoparticles and polyzwitterion as a top layer. Embedding of silver nanoparticles and polyzwitterion coating were confirmed by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The effectiveness of biocide release from the modified membranes was evaluated with Pseudomonas putida (P. putida) and Escherichia coli (E. coli) and the anti-adhesion property was studied using P. putida. The silver nanoparticles embedded within PEMs showed biocidal property because of silver ion release, and polyzwitterion at the top layer showed high anti-adhesion properties because of the high hydrophilicity of surface. Thus, the membrane modified by PEMs embedded with silver nanoparticles and polyzwitterion as a top layer showed a high antibiofouling properties, attributed to the combined effect of biocide release and adhesion resistance.

► Commercial RO membrane was modified with polyelectrolyte multilayers deposition.
► Ag nanoparticles were embedded into multilayers.
► Ag nanoparticles in multilayers enhanced a release killing property for bacteria.
► Polyzwitterion layer was deposited a top coat to enhance anti-adhesion property.
► Anti-biofouling property of membrane was greatly improved by a combination of two effects.