Microfiltration System

Share  | 

Microfiltration uses microporous membrane to remove contaminants from a fluid. The function of microfiltration in principle is as same as that of reverse osmosis, ultrafiltration and nanofiltration. The difference lies in terms of retention of the size of molecules. The pore size of microfiltration membrane range from 0.1 to 10 µm.

Through microfiltration, suspended solids, bacteria or other impurities can be easily removed. The membrane used in microfiltration is porous enough to pass molecules of true solutions, even if they are large. Due to the small pores used in microfiltration, it can be used for sterilizing solutions.

Mechanism and Properties of Microfiltration
Adsorption and entrapment are the mechanism used for the conventional depth filtration whereas, microfiltration uses sieving mechanism. The filter with different pore sizes are used for retaining larger size particles than the pore diameter. This technology therefore can be used for various critical operations like sterile filtration of parental fluids, free-water for the electronics industry etc.

The materials used for making microfiltration membranes are natural or synthetic polymers like cellulose nitrate or acetate, polyvinylidene difluoride (PVDF), polyamides, polysulfone, polycarbonate, polypropylene etc. Apart from this some inorganic materials like alumina, glass, zirconia coated carbon etc. are also used for manufacturing the MF membranes.

Selection Criteria of Microfiltration membrane
Microfiltration membrane should be selected keeping following aspects in mind:

• Mechanical strength of the membrane
• Their resistance to temperature
• Chemical compatibility of the membrane
• Hydrophobility, Hydrophilicity and Permeability of the membrane
• Cost and the manufacturing process of the membrane material.

Applications of Microfiltration
Microfiltration produces of high purity and quality. The applications include:

Water Treatment and production

• Prior to other membrane treatment they are used for the pretreatment of surface water, seawater and municipal effluent.
• They are useful for producing

Drinking water
Irrigation
Industrial water reuse and makeup water

Dairy industry

• Microfiltration is used for removing bacteria and spores from cheese milk, milk for powder production and market milk
• They also serve the same functions for whey
• They help in the fractionation of milk proteins
• For high protein WPC they serve the purpose of defatting the whey
• For sanitation of cheese brine, they remove bacteria, spores, yeast and mould.

Others

• In chemical industry
• Microelectronics industry
• Fermentation
• producing sterile water for pharmaceutical industry
• Food & beverages industry where the process is used for concentrating fruit juices and alcoholic beverages.
• For biomass concentration and separations of soluble products
• Separates solvents from pigments in paints.