Desalination

Desalination of water is the process of reducing the salt content in it to the required standards. Depending on the purpose and scope of the purified water, 50 to 90 percent or more of the salts are removed during the desalination process. Completely desalted, distilled water is not suitable for human consumption, but it is used in various industries.

Several basic methods are used to desalinate water on an industrial scale:

  • reverse osmosis

  • electro-dialysis

  • ion exchange

  • electric deionization.

Reverse osmosis is mainly used in two ways:

  • for the purpose of desalination of brackish or sea water to produce drinking water (softening);

  • at one of the stages of purification to obtain ultrapure distilled water (desalination).

In the process of desalination by the reverse osmosis method, purified water (permeate) is passed under pressure through special membranes, the pores of which are impermeable to salts and other impurities dissolved in water. The method allows you to purify water from regular solution: The method allows you to purify water from true solutions: membranes of reverse osmosis plants trap substances represented in the form of molecules and ions (cations and anions). High-pressure reverse osmosis (hyperfiltration) allows to remove up to 99% of salts from the water.

Electrodialysis makes it possible to extract salts dissolved in the water under the influence of an electric current. The principle of operation of the electrodialysis installation is as follows. Two types of membranes are alternately arranged in the solution to be treated: some pass cations, but retain anions, the others - vice versa. Under the action of an electric current, cations and anions of salts dissolved in water begin to move in the opposite direction from each other. In this stream, cations are trapped in the anion exchange membrane, and anions in the cation exchange membrane. As a result, between one pair of membranes, the salt concentration increases, between the next pair - decreases. The solution to be purified is divided into concentrate and diluent.

Ion exchange is the most often used method in water desalination processes. The removal of anions and cations salts out of the solution is carried out by adding special chemicals - ion exchangers. Ionites or ion-exchange sorbents, have the ability to exchange their ions for ions contained in the surrounding solution. Reacting with ions of salts contained in water, ion exchangers "collect" them, increasing in size and bonding, and then being removed.

The electrodeionization method combines the advantages of ion exchange and electrodialysis. The technology is applied to obtain a high degree of purification (distilled water).

The Mirrico Group Water Technologies and Service division supplies equipment based on ion exchange and reverse osmosis technologies for desalination and water treatment at enterprises in various industries and utilities.

The equipment of Mirrico Group has the following advantages:

  • High purification speed, which allows to process large volumes of water with less equipment and reagent requirements.

  • High purification quality (removal of salts to the required levels).

  • Long service life of the equipment.

  • Profitability - applied desalination technologies can reduce the cost of feed materials and reagents.

  • Maneuverability (the ability to use a different degree of equipment performance).

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