History of Nanofiltration Membranes from 1960 to 1990

The history of nanofiltration (NF) development is unique and began in the 1960s based on the realization that membrane selectivity in the region between those of reverse osmosis (RO) and ultrafiltration (UF) membranes, under active development at that time, can be viewed as a distinct and unique discipline as many practical applications within this range of selectivities were beginning to be recognized. Thus, NF membrane technology was developed through the initial phases of 1960-1990 for use in many industrial applications. For example, developments in product purification during chemical manufacturing, with concurrent waste stream minimization, and recycling of environmentally damaging caustic and acid solutions were used for vessel cleaning in the chemical and food industries. Solvent-stable and oxidant-stable NF membrane development also began in this period, with many potential applications. For these and other NF membrane applications, we describe the developments in the 1960s-1990s of integrally skinned asymmetric membranes from different polymeric materials, composites such as polymeric coatings and interfacial polymerization of submicron selective coatings on UF supports, and the development of NF ceramic and inorganic membranes. These developments in NF were the basis of subsequent developments in NF technology as described in subsequent chapters of this book.