Enhanced Fouling Resistance and Antimicrobial Property of Ultrafiltration Membranes Via Polyelectrolyte-Assisted Silver Phosphate Nanoparticle Immobilization

Abstract

Ultrafiltration (UF) is a low-pressure membrane that yields higher permeate flux and saves significant operating costs compared to high-pressure membranes; however, studies addressing the combined improvement of anti-organic and biofouling properties of UF membranes are lacking. This study investigated the fouling resistance and antimicrobial property of a UF membrane via silver phosphate nanoparticle (AgPNP) embedded polyelectrolyte (PE) functionalization. Negatively charged polyacrylic acid (PAA) and positively charged polyallylamine hydrochloride (PAH) were deposited on the membrane using a fluidic layer-by-layer assembly technique. AgPNPs were immobilized within the crosslinked “bilayers” (BL) of PAH/PAA. The effectiveness of AgPNP immobilization was confirmed by microprofile measurements on membrane surfaces using a solid contact Ag micro-ion-selective electrode. Upon stable and uniform BL formation on the membrane surface, the permeate flux was governed by a combined effect of PAH/PAA-derived hydrophilicity and surface/pore coverage by the BLs “tightening” of the membrane. When fouled by a model organic foulant (humic acid), the functionalized membrane exhibited a lower flux decline and a greater flux recovery due to the electrostatic repulsion imparted by PAA when compared to the unmodified membrane. The functionalization rendered antimicrobial property, as indicated by fewer attachments of bacteria that initiate the formation of biofilms leading to biofouling.

Nanoparticle-Embedded Polymers and Their Applications: A Review

“…The use of this technology under certain conditions enhances a membrane's resistance to fouling since, under regular use, membranes are susceptible to fouling, Membranes 2023, 13, 537 2 of 26 causing their performance to degrade over time. Significant improvements and modifications should be made to polymeric membranes before they can be used sustainably [7]. The incorporation of nanoparticles into polymeric membranes, when using different types of materials, has the potential to cause a synergistic effect [8].…”

Advanced Polymeric Nanocomposite Membranes for Water and Wastewater Treatment: A Comprehensive Review

“…This paved the way for the exploration of nanomaterials to generate unique morphologies for preferential water flow and excellent salt rejection. Incorporation of NPs in TFNC contributes to the enhancement of membrane properties such as enhanced hydrophilicity, water permeability/flux, excellent salt rejection, removal of organic and inorganic contaminants, and enhanced resistance to chlorine and fouling [ 41 , 115 , 116 , 117 , 118 ]. TFNC polymeric membranes have drawn considerable attention in the past decade (as shown in Figure 3 ).…”

Application of Cyclized Polyacrylonitrile for Ultrafiltration Membrane Fouling Mitigation

“…Membrane contaminants such as proteins, microorganisms, and colloidal solids can deposit on a membrane surface and block pores, which has an adverse effect on membrane performance as a result of reduced fluxes, changing membrane selectivity, increased operating costs, and shortened membrane life cycles [ 12 , 13 ]. Therefore, a highly relevant step is to modify UF membranes to overcome membrane fouling and enhance water fluxes [ 14 , 15 , 16 ]. Common methods include coating and grafting on the membrane surface [ 17 , 18 ].…”