Reverse osmosis is the use of pressure difference as the power of membrane separation and filtration technology, originated from the United States in the 1960s aerospace science and technology research, and gradually transformed into civilian, has been widely used in scientific research, medicine, food, beverage, seawater desalination and other fields。Infiltration is a physical phenomenon, when two kinds of water containing different concentrations of salts, such as using a semi-permeable film to separate it will be found that the water on the side with less salt will permeate through the film into the water with a high salt content, and the salt contained in it is not permeable, so that the salt concentration on both sides will gradually melt to equal so far。This process is called natural osmosis。Reverse osmosis is a method of separating the solute from the solvent in the solution by means of the selective interception of the semi-permeable membrane under pressure。
The composition of reverse osmosis equipment is a set of water treatment system organized around the reverse osmosis membrane. A complete reverse osmosis system is composed of a pre-treatment part, a reverse osmosis host (membrane filtration part), a post-treatment part and a system cleaning part:
First, the pretreatment is often composed of quartz sand filter device, activated carbon filter device, precision filter device, the main purpose is to remove the sediment contained in the raw water, rust, colloidal substances, suspended matter, pigment, odor, biochemical organic matter, reduce the residual ammonia value of water and pesticide pollution and other harmful substances。If the content of calcium and magnesium ions in the raw water is high, it is also necessary to increase the water softening device, the main purpose is to protect the reverse osmosis membrane from the damage of large particulate matter, so as to extend the service life of the reverse permeation membrane。
Second, the reverse osmosis main engine is mainly by the booster pump，膜壳，Reverse osmosis membrane，Control circuit and other components，It is the core part of the entire water treatment system，The quality of water production mainly depends on this part as long as the model of the film and the model of the booster pump are properly selected，The filtration capacity of the reverse osmosis host can reach more than 99% of the salt in water,Water discharge conductivity can be guaranteed inWithin 10us/cm (25 degrees)。
Third, the post-treatment part is mainly to further treat the pure water made by the reverse osmosis main machine，If the subsequent process is connected to ion exchange or electrical deionization (EDI) equipment，It can produce ultra-pure water for industrial use，If it is used in the civilian direct drinking water process，It is often connected with a post-sterilization device，For example, it can be connected to the paper outside germicidal lamp or ozone generator，The resulting water is drinkable。
Fourth, in order to ensure the normal operation of the reverse osmosis system and extend the service life of the reverse osmosis membrane elements, when the reverse osmosis system operates for a period of time to remove calcium carbonate scale, metal oxide scale in water, biological growth (bacteria, fungi, mold, etc.) and other substances, the system needs to be cleaned。
Application fields and characteristics of reverse osmosis technology:
1.Under the condition of no phase change at room temperature, the solute and water can be separated, which is suitable for the separation and concentration of heat-sensitive substances, and the energy consumption is lower than that of the separation method with phase change。
2.Reverse osmosis membrane separation technology has a wide range of impurity removal。
3.High desalting rate and water reuse rate can trap solute with a particle size of more than a few nanometers。
4.Using low pressure as the membrane separation power, the separation device is simple, the operation, maintenance and self-control are simple, and the site is safe and hygienic。
