Kalvoerotusmenetelmä

Kalvoerotusmenetelmä, also known as membrane filtration, is a separation process that uses a semipermeable membrane to physically separate particles, molecules, or ions from a fluid (liquid or gas). The separation is driven by pressure differences, concentration gradients, or electrical potential. Different types of membranes, characterized by their pore size or other properties, are used to achieve specific separation goals.

The process involves pumping the fluid containing the components to be separated through a module containing the membrane. As the fluid passes over the membrane surface, smaller molecules or ions that can pass through the membrane pores are retained as permeate, while larger molecules or particles are blocked and remain as retentate. The effectiveness of the separation depends on the membrane material, pore size, operating pressure, and the properties of the feed stream.

Kalvoerotusmenetelmä encompasses several distinct techniques, including microfiltration, ultrafiltration, nanofiltration, and reverse osmosis. Microfiltration removes particles down to 0.1 micrometers. Ultrafiltration separates molecules with molecular weights typically above 1,000 Daltons. Nanofiltration allows some salts and divalent ions to pass while retaining larger molecules. Reverse osmosis is the most selective, capable of removing ions and small molecules to produce highly purified water.

This method is widely applied in various industries. It is used in water treatment and wastewater purification, food and beverage processing for clarification and concentration, the pharmaceutical industry for drug purification and sterilization, and in biotechnology for cell harvesting and protein separation. Its advantages include energy efficiency compared to some thermal separation methods, the ability to operate at ambient temperatures preserving sensitive components, and its effectiveness in removing a wide range of contaminants.