Kapillärfiltration

Kapillärfiltration, also known as ultrafiltration, is a process that uses a semipermeable membrane to separate water and small solutes from larger molecules like proteins or cells. This separation occurs under pressure, forcing the fluid through the membrane while retaining the larger particles.

The driving force for kapillärfiltration is the pressure gradient across the membrane. This can be hydrostatic pressure, generated by a pump or gravity, or osmotic pressure, created by a difference in solute concentration. As the fluid moves through the membrane's pores, molecules larger than the pore size are retained, while smaller molecules and the solvent (usually water) pass through.

Kapillärfiltration finds widespread application in various fields. In medicine, it is a key component of hemodialysis and hemofiltration, used to remove waste products and excess fluid from the blood of patients with kidney failure. In laboratories, it is employed for concentrating protein solutions, purifying biological samples, and sterilizing liquids. Industrially, it is used in the food and beverage industry for clarifying juices and milk, and in water treatment to remove suspended solids and microorganisms.

The effectiveness of kapillärfiltration depends on several factors, including the pore size of the membrane, the transmembrane pressure, and the characteristics of the fluid being filtered. Careful selection of the membrane material and operating conditions is crucial to achieve efficient separation and prevent membrane fouling, which can reduce flow rates and efficiency.