When choosing a water purifier, the reverse osmosis membrane is key

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I. The moon landing plan was thwarted by water In 1968, the technical preparations for America’s Apollo moon landing were in full swing, yet the most troublesome obstacle turned out to be something as ordinary as water. At that time, it was calculated that the entire moon landing mission required as much as 6 tons of water, including that needed for equipment and the astronauts. If this water could be reused, only a small amount would be necessary. Therefore, finding ways to recycle and purify industrial wastewater, water used for personal hygiene, and urine became the biggest challenge to overcome. Billions of dollars in investment yielded fruitful results – this is reverse osmosis technology, commonly referred to as RO water, which was a top-secret patent of NASA at that time. 　　II. Decoding Reverse Osmosis (RO) The basic working principle of reverse osmosis is as follows: A specially designed high-pressure water pump is used to increase the pressure of the raw water to 6–9 kilograms per square centimeter, forcing the water to pass through a reverse osmosis membrane with a pore size of only 0.0001 micrometers. Chemical ions, as well as bacteria, fungi, and viruses, cannot pass through and are discharged along with the wastewater; only water molecules and oxygen molecules with a size of less than 0.0001 micrometers are allowed to pass through. This principle achieves water purification without altering the properties of the water or its oxygen content, and it has been hailed by experts as the “Rolls-Royce” among water treatment technologies. 　　Reverse osmosis technology has been used in American submarines, aircraft carriers, and combat ships since the 1970s to convert seawater directly into potable water; currently, 80% of the drinking water in the United States is produced using this technology. In the U.S., reverse osmosis is aptly compared to a \"kidney outside the body.\" 　　In the early 1990s, China began to introduce reverse osmosis technology for use on submarines and warships. In 1992, the central government agencies established an reverse osmosis water plant in Zhongnanhai to supply drinking water specifically for foreign guests and **leaders. It is the core component for achieving reverse osmosis; it is an artificial semipermeable membrane made by mimicking biological semipermeable membranes and possessing certain characteristics. They are generally made of polymer materials. Such as cellulose acetate membranes, aromatic polyhydrazide membranes, and aromatic polyamide membranes. The diameter of surface micropores is generally between 0.5 and 10 nm, and the degree of permeability is related to the chemical structure of the membrane itself. Some polymer materials have a good resistance to salts, but their water permeation rate is not good. Some polymer materials have a chemical structure with numerous hydrophilic groups, resulting in a relatively fast water permeation rate. Therefore, a satisfactory reverse osmosis membrane should have an appropriate permeation rate or desalination efficiency. Reverse osmosis membranes should possess the following characteristics: (1) an efficient desalination rate at high flow rates; (2) high mechanical strength and a long service life; (3) the ability to function at low operating pressures; (4) resistance to chemical or biochemical effects; (5) minimal sensitivity to factors such as pH value and temperature; (6) readily available raw materials for production, simple processing, and low costs. The structures of reverse osmosis membranes are divided into two types: asymmetric membranes and homogeneous membranes. The membrane materials currently in use are mainly cellulose acetate and aromatic polyamides. Its components include hollow fiber type, spiral wound type, plate and frame type, and tubular type. It can be used for chemical unit operations such as separation, concentration, and purification, and is mainly applied in the fields of pure water production and water treatment. Original source of this article: Water treatment equipment http://www.aoliyuan.cn