Reverse osmosis membrane is the core component for achieving reverse osmosis, and is an artificial semi permeable membrane made by simulating biological semi permeable membranes with certain characteristics. Generally made of polymer materials. Such as cellulose acetate film, aromatic polyhydrazide film, and aromatic polyamide film. The diameter of surface micropores is generally between 0.5 and 10nm, and the size of permeability is related to the chemical structure of the membrane itself. Some polymer materials have good salt repellency, while the penetration rate of water is not good. Some polymer materials have a large number of hydrophilic groups in their chemical structure, resulting in a relatively fast water penetration rate. Therefore, a satisfactory reverse osmosis membrane should have an appropriate penetration rate or desalination rate.

There are two types of structures for reverse osmosis membranes: asymmetric membranes and homogeneous membranes. The main membrane materials currently used are cellulose acetate and aromatic polyamides. Its components include hollow fiber type, roll type, plate frame type, and tube type. It can be used in chemical unit operation such as separation, concentration and purification, and is mainly used in pure water preparation and water treatment industries.

1. It should have an efficient desalination rate at high flow rates;

2. Having high mechanical strength and service life;

3. Able to function under low operating pressure;

4. Capable of withstanding the effects of chemical or biochemical processes;

5. Less affected by factors such as pH value and temperature;

6. The source of raw materials for film making is easy, the processing is simple, and the cost is low.