How to systematically maintain and maintain the waterproof and breathable membrane

1. Storage of waterproof and breathable membrane
When the membrane is stored for a long time, it must maintain good performance and have use value, so the life of the waterproof and breathable membrane is an important issue. Therefore, special care should be taken in actual storage.
The storage of waterproof and breathable microfiltration membranes can be divided into wet storage and dry storage. Either way, the purpose is to prevent the hydrolysis of the membrane, prevent the growth and erosion of microorganisms, shrinkage and deformation of the membrane, and the like.
① Wet storage
The key to wet preservation is to always keep the membrane surface wet with the preservation solution. Preservation solution can use the following formula: water: glycerin: formaldehyde = 79.5: 20: 0.5. The role of formaldehyde is to prevent the growth and reproduction of microorganisms on the surface of the membrane and to prevent erosion of the membrane. The purpose of adding glycerin is to lower the freezing point of the preservation solution and prevent damage to the membrane due to freezing. The formaldehyde in the formula can also be replaced by copper sulfate and other fungicides that do not harm the membrane. The preservation requirement of cellulose acetate film is temperature 5～40 ℃, pH=4.5～5, and the temperature and pH of non-cellulose acetate film preservation can be wider.
② Dry storage
Waterproof and breathable microfiltration membranes are often supplied on the market in a dry state, because it is easy to store and transport. In addition, if the wet film is to be stored in a dry method, the film must also be treated by the following methods. The specific method is: the cellulose acetate membrane can be soaked in 50% glycerin aqueous solution or 0.1% sodium dodecylsulfonate aqueous solution for 5-6 days, and dried at a relative humidity of 88%. Polysulfone membranes can be dried at room temperature with 10% glycerin, sulfonated oil, polyethylene glycol and other solutions as dehydrating agents. In addition, the surfactant also has a good effect on the deformation of the pores of the protective film.
2. Problems that should be paid attention to in the maintenance and maintenance of the waterproof and breathable membrane system
The care and maintenance of the membrane system should focus on the following issues.
① According to the different membranes, special attention should be paid to the environment of use, especially the temperature and pH value of the feed liquid, and even the chlorine content in the feed liquid.
② When the membrane system is shut down for a short period of time, attention should be paid to the moisture retention of the membrane, because once the membrane surface loses water without remedial measures, the pores of the waterproof and breathable membrane will shrink and deform, reducing the performance of the membrane.
③ When stopping, avoid contact with high-concentration feed liquid.
④Regularly clean and maintain the membrane with maintenance solution to reduce membrane pollution.
⑤ In use, operate according to the operating conditions that the membrane system can withstand, and avoid long-term overload operation to avoid irreversible damage to the membrane.