ABSTRACT
Studies on membrane technology and its applications started in the eighteenth century.1 The word osmosis was introduced by Abbé Nolet in 1748 to describe permeation of water through a diaphragm. During the nineteenth century, membranes were used only as laboratory tools to develop physical/chemical theories. For example, the measurements of solution osmotic pressure made with membranes by Traube and Pfeffer were used by van’t Hoff in 1887 to develop the limit law, which explains the behavior of ideal dilute solutions. The work led to the van’t Hoff equation. Around the same time, the concept of a perfectly selective semipermeable membrane was used by Maxwell and others in developing the kinetic theory of gases. Different types of diaphragm such as bladders of pigs, cattle, or sh and sausage casings made of animal gut were investigated by early membrane research workers. Later, nitrocellulose membranes were preferred due to reproducibility. Bechhold devised a technique in 1907 to prepare nitrocellulose membranes of graded pore size. Other workers such as Elford,2 Zsigmondy and Bachmann,3 and Ferry4 improved Bechhold’s technique to prepare nitrocellulose membranes. By the early 1930s, microporous membranes were commercially available. During the next 20 years, this microltration (MF) membrane technology was expanded to other polymers, such as cellulose acetate. Membranes found their rst signicant application in the testing of drinking water during the end of World War II when drinking water supplies in Germany and other parts of Europe were broken down, and lters were needed to test for water quality and safety. The research effort to develop these lters, sponsored by the U.S. Army, was later utilized by the Millipore Corporation (Billerica, MA).
