Three-Dimensional Stable Cation-Exchange Membrane with Enhanced Mechanical, Electrochemical, and Antibacterial Performance by in Situ Synthesis of Silver Nanoparticles

In this study, a simple and facile approach was proposed to synthesize silver nanoparticles (AgNPs) loaded cation-exchange membranes (CEMs). A wide analytical study involving scanning electronic microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy was accomplished to corroborate that the in situ generated AgNPs were uniformly dispersed in the polymer matrix. In addition, as a result of the proposed synthesis strategy, the cross-linking structure inside the membrane was formed. The proper particle size and dispersibility of the AgNPs improved the mechanical properties of the membranes. Besides, the optimal AgNP-loaded CEM exhibited excellent bacterial killing activities against Gram-negative bacteria and showed a controlled improvement in the electrochemical performance of the prepared membranes. These effects were caused by the obtained distribution of AgNPs near ion-exchange groups that increased the aggregation of water molecules around them, improving the efficiency of ion transport due the formation of array broad ion-transport channels. The optimized CEM [sulfonated polysulfone (60SPSF)-C3#-Ag-2] exhibited an enhanced NaCl removal ratio of 67.5% with a high current efficiency (96.9%) and a low energy consumption (5.84 kWh kg–1). The distance of the inhibition zone from the boundary of the membrane of SPSF-C3#-Ag-2 reached 4.8 mm. These results led us to suggest that the proposed synthesis strategy may have potential applications in the field of antibacterial and desalting ion-exchange membranes.