9 maja 2017

Microfiltration, Ultrafiltration, Nanofiltration

Microfiltration, Ultrafiltration, Nanofiltration

Microfiltration (MF) is a filtration method using membranes of 0.2 - 10 μm pores. The membrane is a semi-permeable barrier that allows some molecules to pass through and stops others - depending on their size (particles smaller than the membrane's pore diameter can pass). Microfiltration membranes are permeable to ions and nonionic chemicals (some vitamins and dissolved proteins) and retain colloids, suspensions and bacteria.

Exemplary applications:microfiltration
- biomass extraction
- sterilization of culture media
- sterile filtration of milk and brine
- production of unpasteurised beer
- clarification of juices, wine and beer
- wastewater treatment
- pre-filtration of water before reverse osmosis


Ultrafiltration (UF) is also a membrane process, but in this case the membrane pores diameter is usually of several, up to dozens of nanometers, so their size is similar to the size of individual molecules. Ultrafiltration membranes enable molecules of sugars, salts and water to pass through and they retain proteins and larger particles.

Exemplary applications:ultrafiltration
- hemodialysis
- milk and whey production
- starch production
- recovery of dyes in the textile industry
- antibiotic purification
- preparation of water for RO process



Nanofiltration (NF) is a membrane process in which organic compounds with molecular mass above 200-300 u, as well as divalent and higher valent ions, are retained. Asymmetric membranes with pore size of about 1 nm are used. Nanofiltration enables almost complete removal of microbial contaminants.

Exemplary applications:nanofiltration
- technological water sterilization and softening
- water recovery from sewage
- removal of lactose and protein from whey
- surface water and groundwater treatment
- partial desalination of water