ABSTRACT
Membranes have been employed for the treatment of a diversity of fl uids ranging from gases, wastewater, seawater, milk, yeast suspensions, and others [1-22]. Membrane development started with liquid-phase separation processes. In this regard, Nollet carried out the fi rst documented membrane experiment in 1748, using a section of a pig’s bladder as the membrane. As a result of this experiment, he introduced the term “osmosis” [10]. However, the manufacture of asymmetric cellulose acetate membranes in the early 1960s by Loeb and Sourirajan is normally accepted as the fi rst milestone for membrane technology [2]. However, the earliest large-scale gas separation membrane procedure was carried out in the mid-1940s by the U.S. government to separate the different isotopic compositions of UF6 for nuclear fuel enrichment [6]. Nevertheless, commercially important gas separation membrane processes were introduced only in late 1970s and early 1980s [10].
