The commercialization of nitrocellulose microfiltration membranes in the 1830s.
In 1953, Reid of the University of Florida and others first proposed reverse osmosis seawater desalination.
In 1960, the University of California in the United States invented the first generation of high-performance asymmetric Cellulose acetate membrane, and reverse osmosis (RO) was first used for sea wave and brackish water desalination.
In 1961, Hevens Corporation of the United States first proposed the manufacturing method for tubular membrane components.
In 1965, the University of California in the United States produced a tubular reverse osmosis device for brackish water desalination.
In 1970, high-efficiency Aramid hollow fiber reverse osmosis membrane was successfully developed, which further improved the performance of RO membrane.
After the 1980s, membranes that entered industrial applications used pervaporation for dehydration of azeotropic substances such as alcohols.
In the 1990s, low-pressure reverse osmosis composite technology emerged, which greatly improved the performance of the third-generation RO membrane and opened up broad prospects for the development of RO technology
The development history of reverse osmosis membranes:
In 1748, Nollet discovered the phenomenon of infiltration.
In 1920, a complete theory of dilute solutions was established.
In 1953, it was found that Cellulose acetate had good semi permeability.
In 1960, Cellulose acetate reverse osmosis membrane was made for the first time.
In 1970, DuPont invented the aromatic polyamide hollow fiber reverse osmosis device.
In 1980, fully aromatic polyamide composite films and their roll components were introduced.
In 1990, medium pressure, low pressure, and ultra-low pressure high desalination polyamide composite membranes entered the market, opening up broad prospects for the development of reverse osmosis technology.
In 1998, the successful development of low-pollution membranes further expanded the application scope of reverse osmosis. Operating principle of reverse osmosis membrane The membrane that is selective to the substances it penetrates is called Semipermeable membrane. Generally, the membrane that can only penetrate solvent but not solute is called ideal Semipermeable membrane. When the same volume of dilute solution (such as fresh water) and concentrated solution (such as salt water) are placed on both sides of the Semipermeable membrane respectively, the solvent in the dilute solution will naturally pass through the Semipermeable membrane and flow spontaneously to the side of the concentrated solution. This phenomenon is called osmosis. When the permeation reaches equilibrium, the liquid level at the concentrated solution side will be higher than that of the dilute solution by a certain height, which forms a pressure difference, which is called Osmotic pressure. The size of Osmotic pressure depends on the inherent properties of the solution, that is, it is related to the type, concentration and temperature of the concentrated solution, but not to the properties of the Semipermeable membrane. If a pressure greater than Osmotic pressure is applied to one side of the concentrated solution, the flow direction of the solvent will be opposite to the original seepage direction, and the solvent will start to flow from the concentrated solution to the dilute solution. This process is called reverse osmosis. Reverse osmosis is a reverse migration movement of osmosis. It is a separation method that separates solute and solvent in solution by means of selective interception of Semipermeable membrane under pressure. It has been widely used in the purification and concentration of various liquids. The most common application example is that in water treatment process, the impurities such as inorganic ions, bacteria, viruses, organics and colloids in raw water are removed by reverse osmosis technology, To obtain high-quality purified water.
Fundamentals of Reverse Osmosis Technology - What is Reverse Osmosis Membrane
Permeable membranes have long existed in nature, but it was not until 1748 that Nollet discovered the natural diffusion of water into germanium bladder containing alcohol solution that humans discovered the phenomenon of permeation.
In the natural permeation process, the solvent diffuses from low concentration to high concentration through the permeation membrane; Reverse osmosis refers to the diffusion of solvent in concentrated solution to dilute solution through the membrane under external pressure. The Semipermeable membrane with this function is called reverse osmosis membrane, also called RO (Reverse Osmoses) membrane.