Compared with the two-layer composite membrane, the mechanical strength and chemical stability are obviously improved. Different from common water treatment applications, the feed liquid used in special separation is generally a highly polluted and concentrated organic solution or wastewater. High cross flow rate, high pressure, high cleaning frequency and corrosive operating/cleaning conditions (acid, alkali and high temperature, etc.). ) is a common operating condition in special separation process. It is this three-layer membrane structure that ensures the reliability and economy of membrane separation process.
The smoothness of the surface composite film increases, the adhesion of pollutants on the surface film is obviously reduced, the film is not easy to be polluted, and it is easy to clean after being polluted, thus improving the anti-pollution ability of the membrane element and reducing the requirements of the membrane system for fine pretreatment. The latest research of Yale University in the United States proves that the rougher the membrane surface, the easier it is to be polluted. AFM images of atomic force microscope show that colloidal particles will form adsorption accumulation on the rough surface of the traditional two-layer reverse osmosis membrane, which will increase the osmotic resistance of water and reduce the membrane flux, thus blocking the water supply channel and making it difficult to recover after cleaning. The three-layer composite membrane with smooth surface overcomes this shortcoming.
Compared with Dow, Hanshi and Huitong:
Dow Jones > General Electric > General Electric; Han Shi, Huitong, etc