Microporous filtration membraneDue to its high precision and high-throughput characteristics, it is widely used in fields such as biopharmaceuticals, food and beverage, environmental monitoring, and electronic semiconductors. To ensure its filtering effect and extend its service life, the following operating procedures should be followed:
1、 Preparation before use
Choose the appropriate filter membrane
Material selection: Choose compatible filter membrane materials based on the chemical properties of the filter medium.
Hydrophilic materials (such as mixed cellulose ester MCE, polyether sulfone PES, nylon Nylon): suitable for aqueous solutions, biologics, etc.
Hydrophobic materials (such as polytetrafluoroethylene PTFE, polyvinylidene fluoride PVDF): suitable for organic solvents, gas filtration, etc.
Aperture selection: Select the appropriate aperture based on the filtering target (such as 0.1 μ m, 0.22 μ m, 0.45 μ m, etc.).
Sterilization filtration: Usually 0.22 μ m pore size is selected.
Clarification filtration: Optional pore size of 0.45 μ m or larger.
Check the integrity of the filter membrane
Observe the appearance of the filter membrane to ensure no damage, wrinkles, or foreign objects.
Before use, integrity testing (such as bubble point testing, diffusion flow testing) can be conducted to ensure that the membrane seal and pore size meet the requirements.
Preprocessing (if necessary)
Hydrophilic filter membrane: directly used or wetted with pure water.
Hydrophobic filter membrane: It needs to be wetted with organic solvents such as ethanol and then replaced with pure water.
2、 Installation and Connection
Install filter membrane
Place the filter membrane flat in the filter or filter cartridge, avoiding folding or twisting.
Ensure that the filter membrane is tightly attached to the filter sealing ring to prevent leakage.
Connecting pipelines
Connect the filter to the inlet and outlet using sterile tubing.
Ensure that there is no leakage at the connection, and use clamps or fixtures to secure if necessary.
Pre rinse (if necessary)
Pre rinse the filter membrane with a small amount of pure water or buffer solution to remove surface impurities and residues.
3、 Filtering operation
Control filtration pressure
Select the appropriate pressure range based on the filter membrane material and pore size.
Low pressure filtration (such as 0.1-0.3 bar): suitable for liquids that are prone to clogging or high viscosity.
High pressure filtration (such as 1-5 bar): suitable for low viscosity liquids, but it is necessary to avoid exceeding the pressure resistance limit of the filter membrane.
Use a pressure gauge to monitor the filtration pressure and avoid membrane rupture caused by excessive pressure.
Control filtering speed
During initial filtration, the flow rate should be slow, and the flow rate should be gradually increased after a filter cake layer is formed on the surface of the filter membrane.
Avoid membrane blockage or damage caused by excessive flow rate.
Monitor the filtering effect
Regularly check the quality of the filtrate (such as turbidity, microbial content, etc.) to ensure that the filtration effect meets the requirements.
Record parameters such as filtration time, flow rate, pressure, etc. for subsequent optimization.
4、 Cleaning and maintenance
Clean the filter membrane
Reusable filter membrane:
Rinse back with pure water or buffer solution to remove the filter cake layer.
For stubborn stains, soak them in mild cleaning agents such as sodium hydroxide or hydrogen peroxide, and then rinse with pure water.
Disposable filter membrane: Discard it directly after use to avoid reuse.
disinfection and sterilization
High temperature sterilization: suitable for high-temperature resistant filter membranes (such as PES, PVDF), usually sterilized at 121 ℃ for 15-30 minutes.
Chemical sterilization: Soak in disinfectants such as ethanol and hydrogen peroxide, and rinse with pure water.
Storage filter membrane
Unused filter membranes should be sealed and stored in a dry, cool place to avoid moisture or contamination.
The wetted filter membrane should be soaked in pure water or buffer solution to prevent drying and deformation of the filter membrane.
5、 Common problems and solutions
Filter membrane blockage
Reason: There are too many particles in the filtrate, the flow rate is too fast, and the pore size of the filter membrane is too small.
Solution: Reduce flow rate, pre filter large particles, and choose larger pore size filter membranes.
Membrane rupture
Reason: High pressure, improper installation of filter membrane, and insufficient pressure resistance of filter membrane material.
Solution: Reduce pressure, reinstall the filter membrane, and choose a filter membrane with higher pressure resistance.
Leakage of filtrate
Reason: Poor sealing between filter membranes and damaged filter membranes.
Solution: Check the sealing ring and replace the filter membrane.
Decreased filtration efficiency
Reason: Membrane fouling, filtrate temperature too high or too low.
Solution: Clean the filter membrane and adjust the temperature of the filtrate to the applicable range of the filter membrane.
6、 Safety precautions
Operation protection:
Wear gloves and goggles during operation to avoid skin or eye contact with filter membrane fragments or chemical reagents.
Waste disposal:
The used filter membrane may contain harmful substances and should be disposed of according to laboratory or industrial waste disposal regulations.
Equipment maintenance:
Regularly inspect equipment such as filters and pipelines to ensure no leaks or damage.
summary
Microporous filtration membraneThe correct use requires full control from selection, installation, operation to maintenance. By selecting filter membrane materials and pore sizes reasonably, strictly controlling filtration conditions, and regularly cleaning and maintaining, stable filtration efficiency can be ensured, the service life of the filter membrane can be extended, and the cost of use can be reduced.