How to carry out systematic maintenance and maintenance of waterproof breathable membrane

First, the preservation of waterproof breathable membrane

When the membrane is stored for a long time, it must maintain good performance and external energy to have use value, so the life of waterproof and breathable membrane is an important issue. Therefore, special attention should be paid to the actual storage.

Waterproof and breathable microfiltration membranes are stored in two ways: wet storage and dry storage. Either way, the purpose is to prevent hydrolysis of the membrane, 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 with preservation solution in a moist state. The following formula can be used for the preservation solution: water: glycerol: formaldehyde = 79.5: 20 : 0.5. The function of formaldehyde is to prevent the growth and reproduction of microorganisms on the surface of the membrane and prevent the erosion of the membrane. The purpose of adding glycerin is to reduce the freezing point of the preservation solution and prevent the membrane from being damaged by freezing. The formaldehyde in the formula can also be replaced by copper sulfate and other fungicides that are not harmful to the membrane. The preservation requirements of cellulose acetate film are temperature 5~40℃, PH=4.5~5, and the temperature and pH of non-cellulose acetate film can be wider.

② Dry preservation

Water-repellent and breathable microfiltration membranes are often marketed as dry membranes because of their ease of storage and transportation. In addition, if the wet film is to be replaced by a dry method, the film must also be treated by the following methods before proceeding. The specific method is as follows: 50% glycerin aqueous solution or 0.1% sodium dodecyl sulfonate aqueous solution can be used to soak the cellulose acetate membrane for 5 to 6 days, and the membrane is dried at a relative humidity of 88%. Polysulfone membranes can be dried at room temperature with 10% glycerol, sulfonated oil, polyethylene glycol and other solutions as dehydrating agents. In addition, the surfactant also has a good effect on the deformation of the protective film pores.

Second, the maintenance and maintenance of the waterproof and breathable membrane system should pay attention to the problems

The maintenance and maintenance of the membrane system should focus on the following issues.

① According to the difference of the membrane, special attention should be paid to the environment of use, especially the temperature, pH value of the feed liquid, and even the chlorine content in the feed liquid.

② When the membrane system is stopped for a short time, attention should be paid to the moisturizing of the membrane, because once the membrane surface loses water and there is no remedy, the pores of the waterproof and breathable membrane will shrink and deform, which will reduce the performance of the membrane.

③When it is stopped, it should avoid contact with high-concentration feed liquid.

④ Regularly wash 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 overloading for long-term operation, so as to avoid irreversible damage to the membrane.