Membranes around us

Membranes can be used to satisfy many of the separation requirements in all segments of human life. A membrane is a permeable or semi-permeable phase, organic or inorganic., which restricts the motion of certain species. Membrane separation processes are based on filtration methods found all around us in nature. The technology incorporates microscopic pores that are much smaller in size than common contaminants, minerals, bacteria and viruses. This physical barrier only allows pure solvent to pass through and has revolutionized the way in which the world treats and manages its liquid and gaseous streams. Membranes are used for various separations: the separation of mixtures of gases and vapors, dissolved solids and solutes from liquids, and miscible liquids. Membrane separation processes are widely used in environment protection, mainly in water and wastewater treatment. At present most of desalination units all over the world use reverse osmosis process for production of desalted water. In gas separation technology membranes are involved in separation of noncondensable gases: nitrogen from air; carbon dioxide from rnethane; and hydrogen from nitrogen, argon, or methane. In almost all industries we can find membrane systems. They are used in substrates preparation or in actual production line. At present membranes squeezed out conventional separation processes in food (dairy industry, beverage production). Membranes are also commonly used in medical therapy, for example as artificial organs (well known artificial kidney). The large market of membranes is connected with non-separation applications like drug delivery systems, disposal diapers, waterproof clothing, and artificial organs.