(2) Water softening equipment
(1) Ion exchanger
The ion exchanger is a device commonly used in water treatment at present. It can soften or demineralize water by selecting a certain process. It mainly uses some ion exchangers to temporarily fix the unwanted ions in the raw water, so that the content of these ions in the water is reduced to the required level. The ions fixed by the exchanger are released in the regeneration solution, and the exchanger can be reused. That is to say, its essence is the physicochemical reaction between the insoluble electrolyte (resin) and another electrolyte in the solution, that is, the exchange reaction between the exchangeable ions on the resin and other ions of the same nature in the solution.
(2) Electrodialyzer
Electrodialysis is a new technology of separation, concentration, purification and recovery process in industry, and is widely used in chemical, pharmaceutical, food and other industries. The application in the food industry is currently mainly focused on the purification of soda water and beer water, and is used to soften (desalinate) water in soft drink factories. Electrodialysis technology is through an ion exchange membrane with selective permeability and good conductivity, under the action of an external DC electric field, according to the principle of opposite sex attracting and same sex repulsion, the anions and cations in the raw water pass through the anion exchange membrane and the anion exchange membrane respectively. A technology that achieves purification by cation exchange membrane.
(3) Reverse osmosis equipment
Reverse osmosis is a membrane technology with relatively large application scale and relatively mature technology. Its application accounts for about half of the entire membrane separation field, which is a major breakthrough in the development of membrane technology. Reverse osmosis is to separate the solvent from the solution through the reverse osmosis membrane. The application of reverse osmosis has developed from seawater desalination, hard water softening, etc. to the concentration of vitamins, antibiotics, hormones, etc., the separation of bacteria and viruses, and the concentration of fruit juice, milk, coffee, etc. It is widely used. The advantages of reverse osmosis equipment are continuous operation, stable product water quality; no need for acid-base regeneration; no shutdown due to regeneration; saving backflushing and cleaning water; producing ultrapure water with high yield (the yield can be as high as 95%); regeneration Sewage does not require water treatment facilities; low operation and maintenance costs; simple installation and low cost.
There are two keys to the production of pure water in reverse osmosis facilities: one is a selective membrane, which we call a semi-permeable membrane, and the other is a certain pressure. Simply put, there are numerous pores on the reverse osmosis semipermeable membrane, and the size of these pores is equivalent to the size of water molecules. Since bacteria, viruses, most organic pollutants and hydrated ions are much larger than water molecules, they cannot penetrate. It is separated from the water phase of the reverse osmosis membrane through the reverse osmosis semipermeable membrane. Among the many impurities in water, soluble salts are more difficult to remove. Therefore, the water purification effect of reverse osmosis is often determined according to the level of salt removal rate, and the level of reverse osmosis salt removal rate is mainly determined by the selectivity of reverse osmosis semipermeable membrane. At present, the salt removal rate of the highly selective reverse osmosis membrane element can be as high as 99.7%.
For reverse osmosis separation, a preferential adsorption layer must first be formed at the membrane-solution interface. The degree of preferential adsorption depends on the chemical properties of the solution and the chemical properties of the membrane surface. As long as the appropriate membrane material is selected, and the microstructure of the membrane surface is simply changed. Pore structure and operating conditions, reverse osmosis technology can be applied to any degree of separation of solute separation.
