Applications
Distinct features of membranes are responsible for the interest in using
them as additional unit operation for separation processes in fluid processes.
Some advantages noted include:
· Less energy-intensive, since they do not require major phase changes
· Do not demand adsorbents or solvents, which may be expensive or difficult to handle
· Equipment simplicity and modularity, which facilitates the incorporation of more efficient membranes
Membranes are used with pressure as the driving processes in membrane filtration of solutes and in reverse osmosis.
In dialysis and pervaporation the chemical potential along a concentration gradient is the driving force.
Also pertraction as a membrane assisted extraction process relies on the gradient in chemical potential.
However, their overwhelming success in biological systems is not matched by their application. The main reasons for this are named
· Fouling - the decrease of function with use
· Prohibitive cost per membrane area
· Lack of solvent resistant materials
· Scale up risks