1. The first methods to separate salt from water are freezing, electrodialysis, distillation, reverse osmosis and ammonium carbonate ion exchange.
2. Secondly, if only the salt is kept, the salt water is directly heated by an alcohol lamp, so that the water evaporates, the temperature is lowered, and the solubility of the salt is reduced, so that the salt water enters a supersaturated state, and salt crystals can be precipitated from the salt water.
Then, if you want to keep the water, separate the salt from the water by distillation.
Finally, pay attention to the burning matches when lighting the alcohol lamp, and don't use the burning alcohol lamp to light it. Don't blow with your mouth, in case the alcohol in the lamp burns and causes an explosion.
Freezing method, a construction method, was first used for gold mining in Russia and then used by German engineers for coal mine construction. Patented technology has matured and has been widely used in subway, deep foundation pit, mine construction and other projects.
Electrodialysis is to make use of the selective permeability of ion exchange membrane under the action of external DC electric field to make anion and cation in solution migrate, and then pass through anion exchange membrane and cation exchange membrane respectively to achieve the purpose of desalination or concentration.
Distillation is a common method for separating and purifying liquid mixtures, and it can also determine the boiling point of liquid compounds, so it is of certain significance for the identification of pure liquid compounds. Reverse osmosis refers to the process of applying an external pressure higher than the osmotic pressure of the solution on the raw water side of the semi-permeable membrane. When raw water passes through the semi-permeable membrane, only water is allowed to pass through, and other substances cannot pass through and are trapped on the membrane surface.
Preparation of pure water by ion exchange, preparation of ion exchange resin, preparation of catalyst by ion exchange, preparation of cation exchange resin, preparation of anion exchange resin and ammonium carbonate ion exchange method.