Various polymer separation membranes are widely used in nuclear fuel and metal refining, gas and hydrocarbon separation, desalination of seawater and brackish water, preparation of pure water and ultrapure water, environmental protection and sewage treatment.
For mixture systems that are difficult to separate, such as near boiling point mixture, * * boiling point mixture, isomer mixture and some heat-sensitive substances, effective separation can be realized. The energy required for seawater desalination by reverse osmosis is only 1/2 of that by freezing method and117 of that by evaporation method, which is simple in operation and low in cost. Therefore, reverse osmosis tends to gradually replace multi-stage flash evaporation. Membrane separation is used in concentrated natural fruit juice, dairy processing, wine making and other food industries, because it does not need heating, it can maintain the original flavor of food. Oxygen-enriched air can be easily obtained by medical polymer oxygen-enriched membrane. It can also be used to prepare ultra-pure water for electronic industry and aseptic medicine. Artificial kidney and artificial lung assembled with separation membrane can purify blood and treat patients with renal insufficiency. Oxygenator is used in artificial heart-lung machine for operation. Since 1980s, polymer separation membranes have developed in the direction of high efficiency, high selectivity, complex functions and various forms. The preparation of asymmetric composite films and ultra-thin films of polymer materials is very active. Membrane separation technology shows great potential in the fields of new energy, bioengineering and new chemical technology.