Separation, as an important production link in the chemical industry, can have many processes and methods. Based on the different physical and chemical properties of the separated objects, there can be many methods such as gel chromatography, ion exchange, crystallization, distillation, centrifugation, extraction, adsorption, etc. The membrane separation technology represented by polymer membranes, as a new and efficient fluid separation, purification, and concentration technology, has been widely applied due to its advantages of mostly no phase changes in the operating process, continuous operation at room temperature, simple and easy amplification, high efficiency, energy conservation, and low pollution.