Silver-containing polyelectrolyte films for biofouling-resistant membranes
- Graduate student: Srividhya Kidambi (Chemistry, MSU)
- Primary Adviser: Dr. Merlin Bruening (Chemistry, MSU)
- PERMEANT collaboration: Dr. Anatoly Burban (UKMA), Dr. Viktoriya Konovalova (UKMA)
One of the ubiquitous challenges in membrane-based, water purification technologies such as reverse osmosis and nanofiltration is minimization of membrane fouling by particles, natural organic matter, and microbes. Biofouling is particularly difficult to control because even a few bacteria on a membrane surface can eventually multiply to form detrimental films. Silver has a long history as an antimicrobial agent and is particularly attractive for membrane modification because it possesses antibacterial properties for a wide spectrum of bacterial strains without being highly toxic to human cells. Ag nanoparticles may provide much greater longevity than Ag + salts for antifouling applications because they dissolve more slowly. This research aims at utilizing the antibacterial properties of Ag nanoparticles to prepare membranes that provide sustained resistance to bacterial growth.
To efficiently deposit Ag nanoparticles at the surface of a membrane, we employ layer-by-layer deposition of a polyimine-Ag + complex and a polyanion such as poly(styrene sulfonate). Reduction of the Ag + with NaBH 4 results in the formation of nanoparticles on the membrane surface. Our current research is examining the rate of leaching of Ag from nanoparticle-modified membranes and the ability of these membranes to resist fouling by bacteria during nanofiltration. SEM images show that the Ag-containing films do not allow bacterial growth, while filtration studies clearly demonstrate a lower fouling rate with modified membranes.