Resumen:
|
Consulta en la Biblioteca ETSI Industriales (8332)
[eng+ A membrane is a layer of material which serves as a selective barrier between
two phases and remains impermeable to specific particles, molecules, or substances
when exposed to the action of a driving force. Some ...[+]
[eng+ A membrane is a layer of material which serves as a selective barrier between
two phases and remains impermeable to specific particles, molecules, or substances
when exposed to the action of a driving force. Some components are allowed
passage by the membrane into a permeate stream, whereas others are retained by it
and accumulate in the retentate stream.
According to their size, membranes can be of various thickness, with
homogeneous or heterogeneous structure. They can also be classified according to
their pore diameter. According to IUPAC, there are three different types of pore size
(dp) classifications:
- Microporous ¿ dp < 2nm
- Mesoporous ¿ 2nm < dp < 50nm
- Macroporous ¿ dp > 50nm
Referring to membrane¿s history, they have two basic and independent histories:
- Microporous membranes became commercial in Germany in small quantities
prior to WW II.
- Reverse Osmosis membranas were originally developed, from cellulose
acetate, in the early 1960's at the University of California as a means to
desalinate seawater. The late 1960's and 70's saw the formation of most of
today's best-known and largest membrane manufacturing companies.
Membranes can be neutral or charged, and particles transport can be active or
passive. The latter can be facilitated by pressure, concentration, chemical or
electrical gradients of the membrane process. Membranes can be generally
classified into three groups: inorganic, polymeric or biological membranes. These
three types of membranes differ significantly in their structure, but what it is studied in
this project are the polymeric membranes.
[-]
|