The advantages and disadvantages of water treatment membrane technology
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Update time : 2023-04-14 11:23:59
The advantages and disadvantages of water treatment membrane technology (ultrafiltration, nanofiltration, reverse osmosis) are deeply analyzed
Comparison of nanofiltration membrane, reverse osmosis membrane and ultrafiltration membrane
Nanofiltration membrane: can trap nanometer scale (0.001 micron) material. The operation interval of nanofiltration membrane is between ultrafiltration and reverse osmosis, its molecular weight of organic matter interception is about 200-800, the interception capacity of dissolved salts is between 20%-98%, the removal rate of soluble univalent ions is lower than that of high-priced ions, nanofiltration is generally used to remove organic matter and pigment in surface water, hardness and radium in groundwater, and partial removal of dissolved salt. Extraction and concentration of useful substances in food and medicine production. The operating pressure of nanofiltration membrane is generally 3.5-30bar.
Reverse osmosis membrane: It is one of the most refined membrane separation products, which can effectively trap all dissolved salts and organic matter with molecular weight greater than 100, while allowing water molecules 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 1 and 20nm. Ultrafiltration membrane allows small molecules and dissolved solids (inorganic salts) to pass through, while trapping colloids, proteins, microorganisms and macromolecular organics. The operating pressure of ultrafiltration membrane is generally 1-5bar.
Ultrafiltration membranes and differences between 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 pass through, left on one side of the membrane, so that the macromolecular material has been partially purified.
Nanofiltration: Nanofiltration, 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%, but if the water quality is not very high, the use of nanofiltration can save a lot of cost.
Reverse osmosis: Reverse osmosis, is the use of pressure gauge difference as the power of membrane separation and filtration technology, 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.
The advantages and disadvantages of reverse osmosis membrane and ultrafiltration membrane
The aperture of reverse osmosis membrane is only 1/100 of the proportion of ultrafiltration membrane size, so reverse osmosis water treatment equipment can effectively remove heavy metals, pesticides, trichloromethane and other chemical pollutants in the water quality, ultrafiltration water purifier is powerless to this. And ultrafiltration water purifier can remove particulate pollutants and bacteria, reverse osmosis all-around removal.
The core components of reverse osmosis and ultrafiltration are both membrane components, and there are two main differences:
1. The effluent water quality is different from the testing standards of the health department. Give you an example to illustrate that the effluent bacteria index, ultrafiltration according to the "general water quality processor", the total number of colonies is 100 / ml; And reverse osmosis water treatment equipment is 20 / ml, the requirements are more strict, of course, reverse osmosis water treatment equipment effluent water quality is much better than ultrafiltration.
2. reverse osmosis water treatment equipment is divided water supply, pure water for drinking, concentrated water for washing; Ultrafiltration is generally used for washing water; When the quality of tap water is relatively high, it can also be used as drinking water equipment.
Advantages of ultrafiltration: generally no pump, no power consumption, no electrical safety problems; Fewer joints, low water, failure rate and water leakage probability is relatively low; Simple structure, cheap price; The operation is simple, the cost is low, does not 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 the change of 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.
The advantages of reverse osmosis water treatment equipment: water quality safety, can effectively remove all kinds of harmful impurities in water quality; The effect is better for water supply special occurrence; The outlet taste is better; It can effectively reduce the hardness of water, and the boiling water container is not easy to scale
Application of different membranes in water treatment
Nanofiltration membrane is the preparation of drinking water and deep purification, the application in wastewater treatment A, domestic sewage B, textile, printing and dyeing wastewater C, tannery wastewater D, electroplating wastewater E, papermaking wastewater.
Application of forward osmosis (FO) : seawater desalination, industrial wastewater treatment, landfill leachate treatment
Reverse osmosis membrane: routine application of water purification, application of urban sewage, application of heavy metal wastewater treatment, oily wastewater application, etc.
Comparison of nanofiltration membrane, reverse osmosis membrane and ultrafiltration membrane
Nanofiltration membrane: can trap nanometer scale (0.001 micron) material. The operation interval of nanofiltration membrane is between ultrafiltration and reverse osmosis, its molecular weight of organic matter interception is about 200-800, the interception capacity of dissolved salts is between 20%-98%, the removal rate of soluble univalent ions is lower than that of high-priced ions, nanofiltration is generally used to remove organic matter and pigment in surface water, hardness and radium in groundwater, and partial removal of dissolved salt. Extraction and concentration of useful substances in food and medicine production. The operating pressure of nanofiltration membrane is generally 3.5-30bar.
Reverse osmosis membrane: It is one of the most refined membrane separation products, which can effectively trap all dissolved salts and organic matter with molecular weight greater than 100, while allowing water molecules 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 1 and 20nm. Ultrafiltration membrane allows small molecules and dissolved solids (inorganic salts) to pass through, while trapping colloids, proteins, microorganisms and macromolecular organics. The operating pressure of ultrafiltration membrane is generally 1-5bar.
Ultrafiltration membranes and differences between 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 pass through, left on one side of the membrane, so that the macromolecular material has been partially purified.
Nanofiltration: Nanofiltration, 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%, but if the water quality is not very high, the use of nanofiltration can save a lot of cost.
Reverse osmosis: Reverse osmosis, is the use of pressure gauge difference as the power of membrane separation and filtration technology, 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.
The advantages and disadvantages of reverse osmosis membrane and ultrafiltration membrane
The aperture of reverse osmosis membrane is only 1/100 of the proportion of ultrafiltration membrane size, so reverse osmosis water treatment equipment can effectively remove heavy metals, pesticides, trichloromethane and other chemical pollutants in the water quality, ultrafiltration water purifier is powerless to this. And ultrafiltration water purifier can remove particulate pollutants and bacteria, reverse osmosis all-around removal.
The core components of reverse osmosis and ultrafiltration are both membrane components, and there are two main differences:
1. The effluent water quality is different from the testing standards of the health department. Give you an example to illustrate that the effluent bacteria index, ultrafiltration according to the "general water quality processor", the total number of colonies is 100 / ml; And reverse osmosis water treatment equipment is 20 / ml, the requirements are more strict, of course, reverse osmosis water treatment equipment effluent water quality is much better than ultrafiltration.
2. reverse osmosis water treatment equipment is divided water supply, pure water for drinking, concentrated water for washing; Ultrafiltration is generally used for washing water; When the quality of tap water is relatively high, it can also be used as drinking water equipment.
Advantages of ultrafiltration: generally no pump, no power consumption, no electrical safety problems; Fewer joints, low water, failure rate and water leakage probability is relatively low; Simple structure, cheap price; The operation is simple, the cost is low, does not 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 the change of 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.
The advantages of reverse osmosis water treatment equipment: water quality safety, can effectively remove all kinds of harmful impurities in water quality; The effect is better for water supply special occurrence; The outlet taste is better; It can effectively reduce the hardness of water, and the boiling water container is not easy to scale
Application of different membranes in water treatment
Nanofiltration membrane is the preparation of drinking water and deep purification, the application in wastewater treatment A, domestic sewage B, textile, printing and dyeing wastewater C, tannery wastewater D, electroplating wastewater E, papermaking wastewater.
Application of forward osmosis (FO) : seawater desalination, industrial wastewater treatment, landfill leachate treatment
Reverse osmosis membrane: routine application of water purification, application of urban sewage, application of heavy metal wastewater treatment, oily wastewater application, etc
