Definition and production method of desalinated water

Desalinated water is water that removes or reduces strong electrolytes that are easy to remove to a certain extent. The remaining salt content in the desalinated water should be between 1-5 milligrams per liter.

Method for preparing desalinated water:

① Distillation method involves heating and evaporating saline water, condensing the vapor to obtain desalinated water. Distillation method is commonly used in laboratories to clean containers or prepare solutions, and is suitable for places with high purity requirements in small quantities.

② Ion exchange method allows saline water to pass through an exchange column containing zeolite or ion exchange agent (see ion exchange), while calcium and magnesium ions remain on the exchange column, and the filtered water is desalinated water;

③ Electrodialysis method utilizes the selective permeability of ion exchange membrane to ions, and under the action of an external electric field, the cation and anion in the water between the two ion exchange membranes are respectively concentrated towards the anode and cathode through the exchange membrane.

So the inter membrane zone becomes the freshwater zone, and the outer membrane is the concentrated water zone. The water drawn out from the freshwater area is called desalinated water.

Ion exchange method and electrodialysis method are commonly used in the chemical industry, such as boiler water, to reduce scaling and corrosion, and are suitable for places with large quantities and low purity requirements.