Potential of silver nanoparticle‐coated polyurethane foam as an antibacterial water filter

TLDR

The low‑cost, effective silver‑nanoparticle polyurethane foam filter could have significant impact in developing countries. Silver nanoparticles are coated onto polyurethane foam by overnight immersion, binding through nitrogen atoms, and evaluated in a prototype filter. The coated foam remains uniform, retains its morphology, and eliminates E. coli at 0.5 L/min flow, with nanoparticles stable and not leaching.

Abstract

Abstract Silver nanoparticles can be coated on common polyurethane (PU) foams by overnight exposure of the foams to nanoparticle solutions. Repeated washing and air‐drying yields uniformly coated PU foam, which can be used as a drinking water filter where bacterial contamination of the surface water is a health risk. Nanoparticles are stable on the foam and are not washed away by water. Morphology of the foam was retained after coating. The nanoparticle binding is due to its interaction with the nitrogen atom of the PU. Online tests were conducted with a prototypical water filter. At a flow rate of 0.5 L/min, in which contact time was of the order of a second, the output count of Escherichia coli was nil when the input water had a bacterial load of 10 5 colony‐forming units (CFU) per mL. Combined with the low cost and effectiveness in its applications, the technology may have large implications to developing countries. © 2005 Wiley Periodicals, Inc.