RO (Reverse Osmosis) reverse osmosis technology is a membrane separation and filtration technology that uses pressure gauge differences as power. It originated from the research of aerospace science and technology in the United States in the 1960s, and then gradually transformed into civilian use. Food, beverage, seawater desalination and other fields.
RO reverse osmosis membrane has a pore size as small as nanometers (1 nanometer = 10-9 meters). Under a certain pressure, H2O molecules can pass through the RO membrane, while the source water contains inorganic salts, heavy metal ions, organic matter, colloids, bacteria, viruses, etc. Impurities cannot pass through the RO membrane, so that pure water that is permeable and concentrated water that is impermeable are strictly distinguished.
The conductivity of pure water filtered by RO membrane is 5 s/cm, which meets the third-grade water standard of the national laboratory. After circulating and filtering through an atomic-grade ion exchange column, the effluent resistivity can reach 18.2M.cm, which exceeds the national laboratory water standard (GB682-92).
To be precise, reverse osmosis technology, because the particle size of its own membrane is small enough, can only pass water molecules in the solution, and other substances are throttled, so heavy metal ions can be intercepted.
(1) Nickel-plated wastewater: reverse osmosis treatment of nickel-plated wastewater has been widely used in my country, and dozens of devices are currently in operation. The separation rate of divalent nickel ions is 97.2%-97.7%, the water flux is 0.4 ton/m²*day, and the nickel recovery rate is greater than 99%.
(2) Chromium plating wastewater: reverse osmosis treatment of chromium plating wastewater is widely used in my country. Reverse osmosis membranes mostly use polysulfone amide membranes with excellent acid and oxidation resistance developed by our country. When the concentration of butyric anhydride in chromium-containing wastewater is 5000 mg/L and the operating pressure is 4 MPa, the water flux is 0.16 to 0.2 tons/m 2 *day, and the chromium removal rate is 93% to 97%.