Basic Knowledge Instruction Of Nanofiltration Membrane


The molecular weight cut-off of nanofiltration membrane is between reverse osmosis membrane and Ultrafiltration Membrane, about 200-800 Daltons. Retention characteristics: preferential retention of divalent and multivalent anions, and the retention rate of monovalent ions is related to the concentration and composition of the feed liquid. Nanofiltration is generally used to remove organic matter and pigments in surface water, hardness in groundwater and partially remove dissolved salts, and is used for extraction and concentration of substances in food and biomedical production. The operating pressure of the nanofiltration membrane is generally 3.5-30 bar.

The separation skin layer on the membrane surface may have a nano-scale microporous structure.

Compared with the reverse osmosis membrane, the NaCI removal rate is above 95%. Generally, a membrane with a NaCI removal rate below 90% can be called a Nanofiltration Membrane Manufacturer.

The reverse osmosis membrane has a high removal rate for almost all solutes, while the nanofiltration membrane only has a removal rate for specific solutes.

The pore size of nanofiltration membrane is more than 1nm, generally 1-2nm.

Mainly remove solute particles of about one nanometer, and the molecular weight cut off is 200-1000 Daltons.

Almost all reverse osmosis membranes are made of polyamide, while nanofiltration membrane materials can be made of various materials, such as cellulose acetate, cellulose acetate-triacetate, sulfonated polysulfone, sulfonated polyethersulfone, and aromatic polyamide composite materials and inorganic materials.

Generally, the surface of the nanofiltration membrane forms a polymer electrolyte, so it often has a strong negative charge.


The principle of nanofiltration is the same as that of membrane separation processes such as ultrafiltration and reverse osmosis. Nanofiltration Membrane 8040 is also a membrane separation process driven by pressure difference, which is an irreversible process. The separation mechanism can be described by the charge model (space charge model and fixed charge model), pore model, and electrostatic repulsion and steric hindrance models that have only been proposed in recent years. Compared with other membrane separation processes, an advantage of nanofiltration is that it can retain small molecular weight organics that pass through the ultrafiltration membrane, and can dialyze some of the inorganic salts retained by the reverse osmosis membranethat is, it can synchronize "concentration" and desalination.

Product advantages:

1. Accurate molecular weight cut-off

2. The membrane module is easy to replace

3. No dead angle design, not easy to pollute

4. Imported high-quality membrane materials, large flux and high stability

5. Various specifications of membrane elements are available for selection

6. The packing density of the membrane core is high, and the cost per unit membrane area is low

Scope of application:

1. Demineralized water treatment

2. Chemical wastewater treatment

3. Recycling of precious metals

4. Removal of harmful substances in drinking water

5. Dye decolorization or concentration, heavy metal removal, acid purification

6. Concentration and refining of various proteins, amino acids and vitamins in the fields of food, beverages, and pharmaceuticals