Membrane is a widely used material that finds application in membrane technology. This material enables the process of selectivity and separation. The process includes the use of semi-permeable membrane to segregate the suspended particles and other similar substances from the liquid. This technology differs from the traditional separation process as it segregates minute molecular range particles. Moreover, this technology works without the use of chemicals or additives and requires low energy.
The Gentle Alternative
Membrane filtration is extensively used in various industries for separating various components in a feed stream. This separation is based on the size and shape of micro particles exist within it. The better filtration process results in the fine quality and value of the end product. Membrane consists of fine pores that are measured in (I/m2-h) that further allows only liquid to pass through and restricts the denser particles. The separation of particles is processed by pumping the feed stream across the surface of the membrane. Membrane filtration technique is an alternative and is an advanced version of the previous processes such as spray drying, evaporation and flocculation.
How membrane filtration works?
The principle behind the membrane filtration is very fundamental that it restricts the flow of salt and larger particles and allows water to flow through semi permeable membrane. The liquid is pumped across the membrane of the filter that consists of the fine pores. Liquid particles smaller than the pores are passed forming the permeate and denser particles are restricted and remained behind forming the retentate. The pores of membrane are kept free from blockage using several cleaning methods such as forward flushing, backward flushing and air flushing.
Microfiltration is widely used across several industries as it consumes low energy and is highly cost effective to operate. Microfiltration has various advantages over other filtration techniques as the required cost, packing density and cleaning opportunities are comparatively less. This filtration technique is widely used in food industry as it enables the treatment of heat sensitive matters such as fat, oil globules and bacteria without affecting composition of the stream.
Ultrafiltration (UF) technique is used in the separation of salts, sugar, organic acids as well as other smaller peptides and restricts the entry of other substances like proteins, fats and other polysaccharides. This technique employs the membrane having pores range from 1000-100,000 molecular weights (MWCO). By utilizing this filtration technique, liquid can be separated into two distinct feed streams having different molecular weights.
As its name suggests, the nanofiltration requires very small pores of the membrane lesser than 600 Daltons. Owing to smaller pores size, large molecules and most organic ions are restricted while the other small ions pass through. Widely used in the removal of salt content of brackish water, this nanofiltration is also used as a softening agent. Additionally, this can be used for the production of low alcohol beverages as it only allows passing the alcohol component and stops the color and aroma as retentate through the membrane. This can also be used in the removal of metal ions from the stream.
The process of reverse osmosis (RO) uses a special kind of filtration membranes with minute pores that only allows very small fractions of salts along with water. Moreover, certain kind of organic compounds having less molecular weight are permeable to be passed through the membrane with limited scope. It completely restricts suspended contaminants to ensure the purity of liquid.