Reverse osmosis (RO) is a membrane separation technology that uses pressure difference to drive a solution through a polymer semi-permeable membrane to achieve solvent selective separation. It is widely used in seawater desalination, wastewater reuse, medical dialysis, food processing, and industrial pure water production. The technology originated from biomimetic research on the throat mucosa of American seagulls in the 1950s, was later validated by the Apollo program's water circulation system, and has gradually expanded to military ships and civilian water purification equipment.
The system consists of a pretreatment unit, a high-pressure pump, membrane modules, and a cleaning module. The core reverse osmosis membrane has a pore size of 0.0001 micrometers and a desalination rate of up to 99.5%. Operation requires controlling the influent pH to 3-10, residual chlorine <0.1 mg/L, and water temperature <45℃, and using multi-stage filtration to reduce impurity load. A spiral wound composite membrane module achieves 70% water utilization, operates at a pressure of 6-20 kg, and is equipped with an automatic regulating valve to control the recovery rate. Membrane fouling manifests as a decrease in permeate flow or a reduction in desalination rate, requiring chemical cleaning and pretreatment optimization maintenance. The separation mechanism includes dissolution-diffusion, capillary flow, and hydrogen bonding theories, which explain the adsorption and migration of water molecules within the membrane.