(398ad) Coordinate Immobilization of Silver Nanoparticles on Aminenated Polyethersulfone (AgNPs-APES) Composite Membrane for Prolong and Constant Silver (Ag+) Release

Improving the life time of water treatment membranes can be achieved through exquisite control of active disinfectant release. The present study demonstrates a controllable and systematic novel approach to coordinately immobilize silver nanoparticles (AgNPs) on the surface of aminenated polyethersulfone (APES) composite membrane for prolonged silver (Ag⁺) release to enhance the life of water treatment membrane. Aminenated-polyethersulfone was prepared by nitration of the polyethersulfone (PES) by acid treatment. The obtained nitrated polyethersulfone (NO₂-PES) was subsequently reduced using tin (II) chloride dihydrate (SnCl₂.2H₂O) and sodium iodide (NaI) to form aminenated-polyethersulfone APES or (NH₂-PES). AgNPs were coordinately attached on the surface of APES (AgNPs-APES) by reduction of silver nitrate (AgNO₃)with sodium borohydride (NaBH₄). The physicochemical properties of the as-synthesized membrane were examined by FT-IR, XPS, XRD, TGA, ICP-OES and SEM-EDAX analyses. It was confirmed that the AgNPs ranging from 5-40 nm were immobilized on the surface of polymer membrane. The evaluation of Ag⁺leaching over time of the obtained samples indicated that ~30% of AgNPs could be retained after 12 days from operation of 1cm × 3cm membrane strip. The extrapolation of the data curves confirmed that the membrane can be used up to 25 days. Antibacterial activities of the samples were also carried out to investigate the disinfection performance of the samples on the Gram negative bacteria (Escherichia coli). Generally, the as-synthesized membrane revealed 4 times longer life than AgNPs embedded polymer membranes.