High Performance Nanofiltration Membranes and Hybrid Processes.

Nanofiltration (NF) is a pressure driven membrane process which falls between reverse osmosis and ultrafiltration. In the early 1980's, several thin-film composite type of NF membranes were developed. Since then NF technology has been widely applied in a variety of applications including municipal and industrial water treatment and food processing.NF membrane performance is characterized from its fundamental characteristics such as charge, charge density, molecular-weight cutoff, and pure water permeability coefficient. NF membrane performance can be improved or specialized by adjusting these parameters. Another way to improve membrane processes is to combine NF with any other separation processes which is referred to as hybrid process. In this article the hybrid NF processes are reviewed and their potential benefits are demonstrated in more detail.