Membrane Filtration Technologies In The Laboratory And Beyond

One of the most commonly used types of filtration in the laboratory (and everywhere else as well) is membrane filtration.

Generally speaking, filtration using a membrane is performed by forcing a liquid through a membrane with very small apertures which permit the liquid itself to flow through while trapping particulates. Depending on the size of these apertures, filtration from the very coarse to the extremely fine is possible.

The basic technology is used for everything from small-scale filtration as used in a syringe filter all the way up to membranes which are massive in scale, such as those used in some municipal water filtration systems.

In the laboratory setting, the applications for membrane filtration include barrier separations, where molecules are prevented from passing from one side to the other by means of a membrane of varying size. Ultra filtration methods work much in the same way, with the addition of pressure being introduced to force the liquid from one side of the barrier to the other while straining out any particulates too large to fit through the fine apertures of the semi-permeable membrane being employed in the filtration process.

Barrier separation is used for separation and purification applications in chemistry and life sciences laboratories, as well as in quality control processes in the production environment. A syringe filter works on much the same principle, with the pressure being supplied by the user as the plunger of the syringe is depressed.

Membrane filtration is also used in electrodialysis and reverse osmosis filtration procedures, such as are used in laboratories where very thorough filtration and purification of samples is required; these technologies are also used in water filtration in everything from small home water purification systems to large scale municipal water filtration and desalination plants. In desalination procedures, the membranes used are made from plastics with fine apertures which permit the passage of water while preventing molecules of salt dissolved in the water from passing through, resulting in fresh water on the other side of the filtration system's membrane.

A syringe filter is a common form of membrane filtration in the pharmaceutical and biotechnology laboratory as well as in the clinical research setting; these filters provide a very efficient filtration method for organic solutions and aqueous suspensions where larger scale filtration of these materials would be impractical. These filters may be composed of a variety of different materials, with the membrane filters being housed in heat sealed polycarbonate or polypropylene which is designed to fit onto a specific size of syringe to provide a simple but effective on-board filtration system which is designed to be used for filtration of small quantities of materials in a variety of laboratory applications.

Whether in the form of membrane filtration in barrier separation for chemistry lab applications, large scale filtration for desalination plants or as a syringe filter for use in small scale benchtop applications in the chemistry, life sciences, pharmaceutical or medical research environment, filtration technologies are essential to a variety of scientific and industrial processes.

The technologies used in laboratory and civil engineering filtration have made great advances, with filtration capabilities down to the nanometer now available; and work continues into advancing the state of the art in filtration.