§16§Ultrafiltration first appeared at the end of the 19th century and was used for a long time as a concentration and purification technique in laboratory preparations. Studies have been carried out to improve the properties of ultrafiltration polymeric membranes; most of them are related to flat sheet membranes prepared by the dry/wet phase inversion process. On the other hand, less researches has been done on the preparation and characterization of hollow fiber membranes. This is due to the fact that the preparation of hollow fiber membranes is much more complex than the former which involves various factors such as the rapid phase inversion kinetics and the interfacial mass transfer during the spinning process, as well as the large number of spinning parameters, for example, the structure and dimension of the spinneret, the flow rate of the bore fluid, the composition and temperature of both the bore fluid and external coagulant, the temperature difference between the dope and quen §16§ch medium, polymer dope viscosity, the dope extrusion rate, the fiber wind-up speed, the air gap distance, etc. Nowadays hollow fiber membrane configuration is the preferred option in membrane application
