Preparation and performance of antibacterial layer-by-layer polyelectrolyte nanofiltration membranes based on metal–ligand coordination interactions

Abstract

Coordination interaction between transition metal Cu 2+ ions and polyelectrolyte (PE) ligand is studied to prepare (PEI/PSS(Cu)1/2)n layer-by-layer (LBL) self-assembly (SA) nanofiltration (NF) membranes with unique antibacterial property. The coordination interaction mechanism has been clearly illustrated by X-ray photoelectron spectroscopy (XPS) analysis of the chemical composition of the active skin layer, the result reveals that about one third of the Cu 2+ ions is involved in the interaction. The prepared (PEI/PSS(Cu)1/2)5 LBL membrane owns relative smooth surface morphology and good separation performance, with permeation flux of 65 L m −2 h −1 and rejection of about 84% for SO4 2− at 1.0 MPa. It has excellent antibacterial rate up to 94.2%. The performance of the LBL membranes could be improved, after cross-linking by glutaraldehyde (GA). This kind of LBL NF membrane shows potential application in the separation of monovalent and divalent anions.The influence of bilayer number on the performance of LBL membranes was carried out with five different bilayers (1, 2, 3, 4, 5) prepared using anionic PE solution of 0.4 M CuCl 2 and 0.4% PSS, and cationic PE solution of 0.5 M NaCl and 0.3% PEI. CharacterizationFig.3 The effect of number of bilayers (n=1-5) on rejection (a) and flux (b) of the prepared LBL (PEI/PSS(Cu) 1/2 ) n membranes with different substrates and deposition sequences Fig.7 SEM images of H-PAN substrate and the prepared LBL (PEI/PSS(Cu) 1/2 ) 5 membrane (surface: substrate (a) and (PEI/PSS(Cu) 1/2 ) 5 (b); cross-section: substrate (c) and (PEI/PSS(Cu) 1/2 ) 5 (d)) Fig.8 AFM images of H-PAN substrate (2D images (a) (c) and 3D image (e)) and the prepared LBL (PEI/PSS(Cu) 1/2 ) 5 membrane (2D images (b) (d) and 3D image (f))

Manipulating the multifunctionalities of polydopamine to prepare high-flux anti-biofouling composite nanofiltration membranes

“…Another alternative strategy is to construct antimicrobial membrane surfaces by introducing antimicrobial agents, either organic or inorganic, which could inhibit microbial colonization and prevent biolm formation. [13][14][15][16][17][18][19][20][21][22][23] Silver nanoparticles (AgNPs) have drawn much attention due to the broad-spectrum, long-lasting antimicrobial activity, and in recent years numerous approaches have been explored to fabricate anti-biofouling membranes with presynthesized or in situ generated AgNPs. 20,[24][25][26][27][28][29][30][31][32][33][34][35] Polydopamine (PDA), which can be generated under mild conditions by in situ spontaneous oxidative self-polymerization of dopamine, has been evolved as an emerging material in surface modication, because of its unique multifunctionalities and wide-applicability.…”