Contrast of reverse osmosis membrane, ultrafiltration membrane and nanofiltration membrane
RO reverse osmosis membrane
It is one of the most refined membrane separation products. It can effectively trap all dissolved salts and organic matter with molecular weight greater than 100, while allowing water molecules to pass through. Reverse osmosis membrane is widely used in seawater and brackish water desalination, boiler recharge water, industrial pure water and electronic grade high pure water preparation, drinking water production, wastewater treatment and special separation processes.
Ultrafiltration membrane
It can trap macromolecular materials and proteins between 0.002 and 0.1 micron. Ultrafiltration membranes allow small molecules and dissolved solids (inorganic salts) to pass through, while trapping colloids, proteins, microorganisms and macromolecular organics. The molecular weight range used to represent the pore size of ultrafiltration membranes is generally between 1000-500000. The operating pressure of ultrafiltration membrane is generally 1-7bar.
Nanofiltration membrane
It can trap materials at the nanometer scale (0.001 micron). Nanofiltration membrane operation interval between ultrafiltration and reverse osmosis, its molecular weight of organic matter interception is about 200-800MW, the interception capacity of dissolved salts is between 20%-98%, the removal rate of soluble univalent ions is lower than that of high ions, nanofiltration is generally used to remove organic matter and pigment in surface water, groundwater hardness and radium, And partial removal of dissolved salt, in food and medicine production of useful substances extraction, concentration. The operating pressure of nanofiltration membrane is generally 3.5-30bar.
The differences between ultrafiltration membranes, nanofiltration and reverse osmosis
Ultrafiltration membrane
Ultrafiltration membrane is a pressurized membrane separation technology, that is, under a certain pressure, the small molecules of solute and solvent through a specific aperture of the membrane, while the large molecules of solute can not penetrate, left on one side of the membrane, so that the macromolecular material has been partially purified.
The advantages of ultrafiltration technology are simple operation, low cost, no need to add any chemical reagents, especially the experimental conditions of ultrafiltration technology is mild, compared with evaporation, freeze drying, no phase change, and does not cause changes in temperature, pH, so it can prevent the denaturation, inactivation and autolysis of biological macromolecules. In the preparation technology of biomacromolecules, ultrafiltration is mainly used for desalination, dehydration and concentration of biomacromolecules.
Ultrafiltration also has some limitations in that it cannot directly produce dry powder preparations. For protein solutions, only 10-50% concentration is usually obtained. It can be used for household and industrial purposes. The key to ultrafiltration is membranes. Membrane has a variety of different types and specifications, can be selected according to the needs of the work.
Nanofiltration membrane
Nanofiltration is a cross between ultrafiltration and reverse osmosis. It is now mainly used in water plants or industrial desalination. The desalting rate reached more than 90 percent. The desalting rate of reverse osmosis is more than 99%. However, if the water quality is not very high, nanofiltration can save a lot of cost.
RO reverse osmosis membrane
Reverse osmosis, is the use of pressure gauge difference as the power of membrane separation and filtration technology, originated from the United States in the 1960s aerospace science and technology research, after gradually transformed into civil, has been widely used in scientific research, medicine, food, beverage, seawater desalination and other fields.
Used as space water, purified water, distilled water and other preparation; Alcohol manufacturing and tempering water; Preliminary preparation of water for pharmaceutical, electronic and other industries; Concentration, separation, purification and water preparation of chemical process; Boiler replenishment water desalt soft water; Desalination of seawater and brackish water; Paper making, electroplating, printing and dyeing industry water and wastewater treatment.
