AWWA MTC57560

Nanofiltration (NF) membranes, having properties partially overlapping those of reverse osmosis and ultrafiltration membranes, have the potential capability for removing a broad range of water pollutants including pathogens, organic substances, and inorganic contaminants. Each of these contaminants may pass through a NF membrane by different mechanisms. For example, the permeation of small inorganic molecules could take place by sorption and subsequent diffusion in the membrane active layer, as well as by advection through pores or imperfections produced during membrane manufacturing, installation, or operation. In contrast, the passage of particles including microorganisms through membranes might be mainly the result of advection through larger pores or imperfections. Therefore, an accurate characterization of the pore size distribution (PSD) of the membrane active layer and support layers might assist in elucidating the performance of NF membranes with respect to various types of contaminants. The objective of this study was to elucidate some of the mechanisms responsible for the passage of viruses, organic solutes, and inorganic solutes through nanofiltration (NF) membranes by characterizing the pore size distribution (PSD) of the membranes. Includes 5 references, tables, figures.