How to store PVDF ultrafiltration membrane for a long time?

PVDF ultrafiltration membrane modules should be cleaned before long-term storage, and any of the following solutions should be used as protective solutions:
1. 80~100% glycerol (best), the examples of liquids that can be configured are water: glycerol: sodium bisulfite = 79: 20: 1, the concentration is 1000~5000ppm sodium bisulfite or sodium metabisulfite. Membrane modules stored in sodium bisulfite or sodium metabisulfite need to be rinsed with clean water every 6 months and then soaked with newly prepared liquid medicine. The soaked membrane assembly can be left in the system with all valves closed or the seal and plastic bag removed from the system. The storage conditions for new membrane modules described above are also applicable to the storage of used membrane modules. The stored membrane module should be drained of the protective liquid before being put into use. And clean as above.

2. The temperature of the preservation solution is 5~40℃. The function of sodium bisulfite is to prevent microorganisms from multiplying on the membrane surface and eroding the membrane. The purpose of glycerol is to lower the freezing point of the preservation solution. To prevent damage to the membrane due to icing, the sodium bisulfite in the formula can be replaced by glutaraldehyde, copper sulfate and other bacteriostatic agents that do not harm the membrane.

Attention should be paid to the long-term storage conditions of the membrane, especially in the case of long-term storage, PVDF ultrafiltration membranes, including hollow fiber ultrafiltration membranes and other components must be stored in a state full of protective liquid or water at all times, and must not be allowed to be stored. Dehydration. Once the membrane module is dehydrated and dried, the flux of the membrane will be irreversibly attenuated and cannot be recovered. The wet membrane will shrink and deform due to dehydration, which will greatly reduce the membrane pores, or damage the membrane structure, and at the same time make the texture of the membrane brittle, and even make the filtration effect of the membrane completely invalid.