Question

Write a note on Ultrafiltration method for purification of water.

Answer 1

      Ultrafiltration is a variety of membrane filtration in which forces like pressure or concentration gradients lead to a separation through a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained in the so-called retentate, while water and low molecular weight solutes pass through the membrane in the permeate{filtrate). This separation process is used in industry and research for purifying and concentrating macromolecular solutions, especially protein solutions. Ultrafiltration is not fundamentally different from micro filtration. Both of these separate based on size exclusion or particle capture. It is fundamentally different from membrane gas separation, which separate based on different amounts of absorption and different rates of diffusion. Ultrafiltration membranes are defined by the molecular weight cut off of the membrane used. Ultrafiltration is applied in cross-flow or dead-end mode.

Applications:
1. Filtration of effluent from paper pulp mill
2. Cheese manufacture, see ultra filtered milk.
3. Removal of pathogens from milk
4. Process and waste water treatment
5. Enzyme recovery.