Reverse Osmosis (RO) technology is a membrane separation and filtration technology that uses pressure difference as a power source. It originated from the research of aerospace technology in the 1960s in the United States and gradually transformed into civilian use. Currently, it has been widely used in scientific research, medicine, food, beverage, seawater desalination and other fields.

RO reverse osmosis membranes have pore sizes as small as nanometers (1 nanometer=10)^{-9 (1 billionth of a meter)}Under certain pressure, rice, H2O molecules can pass through the RO membrane, while impurities such as inorganic salts, heavy metal ions, organic matter, colloids, bacteria, viruses, etc. in raw water cannot pass through the RO membrane, thus strictly distinguishing permeable pure water from impermeable concentrated water.

General tap water passes throughThe conductivity of pure water after RO membrane filtration can reach 5 μ s/cm (effluent conductivity after RO membrane filtration=influent conductivity x (1-desalination rate)). Generally, the desalination rate of imported reverse osmosis membranes can reach over 99%, and it can guarantee over 97% within 5 years of operation. For those with high requirements for effluent conductivity, two-stage reverse osmosis can be used, and after simple treatment, the effluent conductivity can be less than 2 μ s/cm, which meets the laboratory's third level water standard. After passing through atomic level ion exchange column circulation filtration or EDI equipment, the effluent resistivity can reach 18.2 M Ω• cm, exceeding the laboratory's first level water standard (GB6682-2008).