We study the adsorption of oppositely charged silica nanoparticles (nominal diameter ranging from (7 to 30) nm) onto porous membrane supports as scaffolding for water purification.  Nanoparticle films of varying thickness, controlled by the number of deposition cycles, were deposited onto the surface of several ultrafiltration membranes of varying molecular-weight cutoffs (i.e. pore sizes).  We characterized the surfaces before and after adsorption of the nanoparticles via optical microscopy, atomic force microscopy and scanning electron microscopy.  The separation performance of the modified membranes was measured using a dead-end filtration cell using concentrated sodium chloride solutions, as captured by the water flux and salt rejection.  We found that the nanoparticle films significantly improve the ability of the membrane to separate dissolved salt from water, even at low numbers of deposition cycles.  Potential mechanisms for the observed separation performance (e.g., pore-blocking and charge repulsion) will be discussed.

Layer-by-layer nanoparticle assemblies as membranes for water purification

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.