Working principle analysis of industrial reverse osmosis equipment

Infiltration is common in nature. For example, if a cucumber is put into salt water, it will lose water and become smaller. The process of water molecules in Cucumber entering saline solution is osmotic process. If a pool is divided into two parts by a membrane through which only water molecules can penetrate, pure water and salt water are injected into both sides of the membrane to the same height. After a period of time, it can be found that the level of pure water decreased, while the level of brine increased. We call the phenomenon that water molecules migrate into brine through this diaphragm osmotic phenomenon. Salt water level rise is not endless, to a certain height will reach an equilibrium point. At this time, the pressure represented by the liquid level difference at both ends of the diaphragm is called osmotic pressure. The osmotic pressure is directly related to the concentration of brine.

After the above device reaches equilibrium, if a certain pressure is applied on the liquid surface of the brine end, the water molecules will migrate from the brine end to the pure water end. The migration of liquid agent molecules from dilute solution to concentrated solution under pressure is called reverse osmosis phenomenon. If salt water is added to one end of the above facility and a pressure greater than the osmotic pressure of the salt water is applied at that end, we can get pure water at the other end. This is the principle of reverse osmosis water purification. There are two keys to producing pure water in reverse osmosis facilities. One is a selective membrane, which we call semi permeable membrane, and the other is a certain pressure.

In short, there are many pores on the reverse osmosis semi permeable membrane, and the size of these pores is equivalent to that of water molecules. Because bacteria, viruses, most organic pollutants and hydrated ions are much larger than water molecules, they can not be separated from water through the reverse osmosis semi permeable membrane. Among all kinds of impurities in water, soluble salts are difficult to remove. Therefore, the water purification effect of reverse osmosis is often determined according to the desalination rate. The desalination rate of reverse osmosis is mainly determined by the selectivity of reverse osmosis semi permeable membrane. At present, the desalination rate of reverse osmosis membrane with high selectivity can be as high as 99.7%.