【Introduction】

Between ultrafiltration and reverse osmosis nanofiltration is between a membrane separation technology, nano-particles larger than 1 retention rate of more than 95%. So it was named "nanofiltration ."
Nanofiltration thin surface layer of a uniform layer of desalination, it is much more than the reverse osmosis membrane to be loose, and the lower operating pressure than RO, it is also called loose-type reverse osmosis nanofiltration or low pressure reverse osmosis.

【Technical requirements and performance indicators】

① For the anion, increasing retention rates in the following order NO3-, Cl-, OH-, SO42-, CO32-;
② For the cations, the order of increasing retention rate of H +, Na +, K +, Ca2 +, Mg2 +, Cu2 +;
③ a price of ion penetration, retention of multivalent ions;
④ between molecular weight cutoff in the 100-1000.
⑤Desalination rate:50-90%

【Applications】
Mainly used in water purification，pharmaceutical, bio-chemical。food industry and other industries。Nanofiltration membranes have higher flux of organic and inorganic pollutants can be retained, and some ions on the human body must have a larger transmission, therefore, the nanofiltration membrane used in deep purification of drinking water than other Membrane separation technology has a greater advantage。