The working principle of

Nanofiltration (NF) is a pressure-driven membrane separation process between reverse osmosis and ultrafiltration. The pore size of nanofiltration membrane is within a few nanometers.

Nanofiltration is a kind of green water treatment technology, which is the latest development of membrane separation technology in the world. In some aspects, it can replace the traditional wastewater treatment method with high cost and complicated process.

Nanofiltration (NF) is used to separate substances with relatively low molecular weight, such as inorganic salts or small organic molecules such as glucose and sucrose, from solvents. Nanofiltration, also known as low pressure reverse osmosis, is an emerging field of membrane separation technology. Its separation performance is between reverse osmosis and ultrafiltration, allowing some inorganic salts and some solvents to pass through the membrane, so as to achieve the separation effect.

Nanofiltration membrane is a charged membrane, which can carry out electrical adsorption. In the same water quality and environment, the pressure required by nanofiltration membrane is less than that of reverse osmosis membrane. So in terms of separation principle, nanofiltration and reverse osmosis are both similar and different. The separation mechanism of nanofiltration membrane is sieving, dissolution and diffusion coexist, and it has charge repulsion effect at the same time. It can effectively remove divalent and polyvalent ions, various substances with molecular weight greater than 200, and partially remove monovalent ions and substances with molecular weight less than 200.