| |
Electromembrane processes generally treat electrolyte solutions between electrodes
separated by ion exchange membranes.
In these processes, the membranes fulfill different functions:
- as separators of the electrodes,
- as selective separators of electrolyte solutions
allowing some ions to pass and block others
according to their charge and size and
- as substitutes for electrolyte in solution (SPE processes).
The selectivity of ion exchange membranes results in a variety of different processes:
- Membrane electrolysis: e.g. caustic/chlorine
production
- Electrodialysis: desalination and concentration
of salt solutions (deutsche Beschreibung,version Francaise )
- Membrane electrolysis: combination of electrode
reactions as a source of hydrogen ions and hydroxide ions with the selectivity
of ion exchange membranes to split neutral salts into their corresponding
acids and bases
- Electrodialysis with bipolar membranes: splitting
of neutral salts into their corresponding acids and bases using bipolar
membranes as a source of protons and hydroxide ions
Salt metathesis: a special electrodialysis process in which two
different diluates (salt ca and salt CA) and two different concentrates (salt Ca and salt cA) are
processes: A change between the salt ions takes place. Example:
Sodium Gluconate + Hydrochloric Acid ----> Sodium Chloride + Gluconic Acid
- Diffusion dialysis
- SPE processes including fuel cell and chemical reactors
The processes are designed for
a concentration and/or dilution of a solution or
a purification and/or isolation of a product from a mixture (removing of salt from sugar solution)
a chemical reaction of salts
the production of new material including hydroxide and protons or other electrode reaction products
|
|
