Does the microporous membrane have to be soaked before use? This question should be discussed from two aspects. Some membranes do not need to be soaked before use, such as PES (polyethersulfone) microporous membranes. They usually do not need to be soaked before use because these membranes are designed to be directly installed and used in filtration systems or other applications; some membranes need to be soaked before use, such as cellulose acetate membranes, mixed cellulose ester (MCE) membranes, including some hydrophobic membranes, etc. Let's focus on this type of microporous membrane that needs to be soaked before use.
What is the purpose and reason for soaking the membrane before use:
1. Soaking the membrane helps hydration, especially for membranes stored under dry conditions. After hydration, the membrane will perform better in terms of filtration efficiency and flow rate.
2. Remove preservatives or storage solutions on or inside the membrane, because some membranes are stored in preservative solutions, mainly to ensure their integrity during storage and transportation. Soaking can remove these solutions and prevent potential interference with the filtration process or the sample being filtered.
3. The role of degassing, soaking the membrane helps to remove any trapped air in the pores, and bubbles in or on the surface of the membrane will affect the interruption of filtration flow.
4. Pretreat the membrane, reasonable soaking is a form of membrane pretreatment to ensure that it is stable and achieves balanced performance in the working environment before actual use.
5. Soaking the membrane in the expected filtration solution before use is a way to test its compatibility with specific samples or buffers, which helps to identify some potential problems before starting the filtration process.
6. Improve the performance of the membrane, pre-soaking puts the membrane in an optimal filtration state, thereby improving the overall performance of the membrane, obtaining better results and extending the service life of the membrane.
7. Reduce membrane fouling, soaking can help reduce fouling and prevent particles from clogging the pores by pretreating the membrane and forming a more stable filtration layer.
8. Leaching can be minimized, because in some applications, soaking can minimize the leaching of membrane components into the filtrate and ensure the purity of the filtered solution.
What are the requirements for the solution used to soak the filter membrane?
The liquid used to soak the filter membrane before use must meet certain requirements to ensure the effectiveness and performance of the membrane, such as the liquid should be compatible with the filter membrane material and the intended application; the liquid used for soaking should be of high purity to prevent the membrane from being contaminated; the soaking liquid should be chemically inert to the membrane material to avoid any reaction that may change the properties of the membrane or impair its performance; the liquid should not degrade or damage the membrane structure; the soaking liquid should not leach components that may contaminate the filtrate or interfere with the filtration process; in some special applications, the buffering capacity of the soaking liquid helps to maintain a stable pH environment; in addition, the sterility, non-foaming, viscosity, solubility, etc. of the soaking liquid are all important factors that must be considered.
In short, before using a microporous filtration membrane, we must first determine whether it needs to be soaked according to its properties, and then determine what kind of soaking liquid to use. Of course, all membrane manufacturers will give reasonable suggestions for the use of membrane soaking, and will also give specific guidance on the type of liquid used and any other pretreatment requirements.
