title: In Situ Reduction of Silver by Polydopamine: A Novel Antimicrobial Modification of a Thin-Film Composite Polyamide Membrane.
abstract: We report a facile method for the antimicrobial modification of a thin-film composite polyamide reverse osmosis (RO) membrane. The membrane surface was first coated with polydopamine (PDA), whose reducing catechol groups subsequently immobilized silver ions in situ to form uniformly dispersed silver nanoparticles (AgNPs) inside the coating layer. Agglomeration of AgNPs was not observed despite a high silver loading of 13.3 ± 0.3 μg/cm(2) (corresponding to a surface coverage of 18.5% by the nanoparticles). Both diffusion inhibition zone tests and colony formation unit tests showed clear antimicrobial effects of the silver loaded membranes on model bacteria Bacillus subtilis and Escherichia coli. Furthermore, the silver immobilized membrane had significantly enhanced salt rejection compared to the control PDA coated membrane, which is attributed to the preferential formation of AgNPs at defect sides within the PDA layer. This self-healing mechanism can be used to prepare antimicrobial RO membranes with improved salt rejection without scarifying the membrane permeability, which provides a new dimension for membrane surface modification.
authors.affiliation: Department of Civil Engineering, The University of Hong Kong , Pokfulam, Hong Kong.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Yang
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798.|Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University , 60 Nanyang Avenue, Singapore 637551.
authors.forename: Yichao
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Civil Engineering, The University of Hong Kong , Pokfulam, Hong Kong.
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Wang
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798.|Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University , 60 Nanyang Avenue, Singapore 637551.
authors.forename: Bin
authors.initials: B
authors.lastname: Cao
authors.affiliation: Department of Civil Engineering, The University of Hong Kong , Pokfulam, Hong Kong.
authors.forename: Chuyang Y
authors.initials: CY
authors.lastname: Tang
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D005374:Filtration; D008567:Membranes, Artificial; D009757:Nylons; D012834:Silver / Q000494:pharmacology*
chemical_list: D000890:Anti-Infective Agents; D008567:Membranes, Artificial; D009757:Nylons; D012834:Silver