RO: Abbreviation of Reverse Osmosis, meaning reverse osmosis and reverse osmosis.
The reverse osmosis phenomenon was discovered by Abble Nellet of France in 1748, and the idea of reverse osmosis was proposed by American Hassler in 1950. However, it was not until 1960 that American scientists Loeb and DR.S. Sourirajan used CA to develop the first reverse osmosis membrane with high separation efficiency and high water permeability, and the reverse osmosis membrane separation became a reality.
It is said that in 1950, the American scientist DR.S. Sourirajan unintentionally discovered that a seagull flew a large mouth from the surface of the sea when it was flying at sea, and after a few seconds spit out a small mouth of seawater, there was a problem because the land was caused by Animals that breathe in the lungs are absolutely unable to drink high-salt seawater. After dissection, it is found that a thin film is formed in the seagull’s body. This film is very precise. The seawater is inhaled by the seagull and pressurized. Fresh water, while the seawater containing impurities and highly concentrated salt is spit out of the mouth. This is the basic theoretical framework of the reverse reverse osmosis method (REVERSEMOSOSMOSIS for short); in 1953, the University of Florida applied seawater desalination to remove salt. In 1960, the United States federal government project supported Dr. S. Sidney Lode of the UCLA University School of Medicine in cooperation with Dr. S. Sourirajan to start research on reverse osmosis membranes. About 400 million US dollars were invested in research each year for use in It was used by astronauts to lift space without carrying a large amount of drinking water, and it was not until 1960 that scholars, Home more and more, so that the amount involved is more sophisticated, from the surface to solve the problem of human drinking water. No wonder Dr. Fritsh said: Research and invention of reverse osmosis membrane is a great contribution to human beings, and even deserves the Nobel Prize.
The percolation phenomenon is common in nature. For example, when a cucumber is placed in salt water, the cucumber will become smaller due to dehydration. The process of the water molecules in cucumber entering the saline solution is the infiltration process. As shown in the figure on the right, if a pool is cut into two parts by a membrane that only water molecules can penetrate, pure water and saline are injected on the two sides of the diaphragm to the same height. After a while, you can see that the level of pure water has decreased, while the level of saline has increased. We call the phenomenon that water molecules migrate through this membrane into salt water. The elevation of the salt water level is not endless, and a certain point will reach an equilibrium point. At this time, the pressure represented by the liquid level difference between the two ends of the diaphragm is called osmotic pressure. The osmotic pressure is directly related to the concentration of saline.Booster pump
After the above device reaches equilibrium, if a certain pressure is applied to the liquid surface of the saline end, at this time, the water molecules will migrate from the saline end to the pure water end. The phenomenon that liquid molecules migrate from a dilute solution to a concentrated solution under pressure is called the reverse osmosis phenomenon. If brine is added to one end of the above facility and a pressure exceeding the osmotic pressure of the brine is applied at that end, we can obtain pure water at the other end. This is the principle of reverse osmosis water purification.
The basic working principle of reverse osmosis: using a special booster pump to add raw water to a certain pressure so that the raw water permeates through a reverse osmosis membrane with a pore diameter of only 0.0001um under the action of pressure;
The key to producing pure water in reverse osmosis facilities is two. 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 semi-permeable membrane. The size of these pores is comparable to that of water molecules. Because bacteria, viruses, most organic pollutants and hydrated ions are much larger than water molecules, they are impermeable. It is separated from the water phase passing through the reverse osmosis semi-permeable membrane. Among the many impurities in water, soluble salts are the most difficult to remove. Therefore, the water purification effect of reverse osmosis is often determined according to the level of salt removal. The degree of salt removal of reverse osmosis is mainly determined by the reverse osmosis semi-permeable membrane. Of selectivity. At present, the salt rejection rate of higher selectivity reverse osmosis membrane elements can be as high as 99.7%.