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Membrane is a thin physical wall which
can be defined as an interface between two adjacent phases
functioning as a selective barrier and regulating the transportation
between them. A thin sheet of natural or synthetic material that is
permeable to substances in solution depends on their physical or
chemical properties. Polymeric-inorganic composite membranes are now
one of the most important classes of engineered materials which
offer several outstanding properties as compared to conventional
membranes. They can be produced from polymers such as PVC,
Polystyrene, and PVA and inorganic materials such as metal
phosphate, tungstate, arsenate, and many metallic oxides are also
used to make the synthetic membrane. The most of commercially
utilized synthetic membranes in separation industries are made of
polymeric and inorganic composites. They can be classified, based on
their surface chemistry, bulk structure, morphology, and the
production method. The chemical and physical properties of synthetic
membranes and a choice of driving force define the membrane
separation processes. Synthetic membranes can be divided into the
categories such as organic (polymeric or liquid), inorganic (ceramic
or metallic), composites (organic inorganic). These composites can
be homogeneous films (polymers), heterogeneous solids (polymeric
mixes and mixed glasses), and liquids. Homogenous membranes are
coherent ion-exchanger gels in the shape of disks, ribbons, etc. The
heterogeneous membranes consist of colloidal ion-exchanger particles
embedded in an inert binder. Membrane based technologies witnessed
much potential to impact multimillion dollar industries in various
sectors such as food/drug production, separation of pollutants,
water purification, textile, biotechnology and to fuel cell markets. |
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Key words: Polymeric-inorganic composite,
Membrane characteristics, Membrane classification, Membrane
applications, Water purification process. |
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