Fabrication of Hollow Fiber Membranes: Effect of Process Parameters (Review)

Hollow fiber membranes originally developed in the 1960s for the reverse osmosis process have since then become widely used for diverse separation processes. The advantages of hollow fiber membranes include the low energy consumption, ease of operation and, among the most important ones, highly efficient operation in a small footprint (a large membrane area can be packed into a module unit). The production of hollow fiber membranes involves many spinning parameters to be controlled. The list of these parameters, in particular, includes the viscosity of the spinning solution, the design and geometric parameters of the spinneret, the extrusion speed of the polymer solution, the composition and temperature of the bore fluid, the type of external coagulant, the air gap distance, the draw ratio, etc. The effect of these parameters on the properties of hollow fiber membranes is reviewed. Research data pertaining to the modification of polymers, both commercially available and at the stage of their synthesis, are also presented in the context of membrane applications. In addition, the preparation of membranes using non-toxic or less toxic solvents is discussed.