Mixedbedjärjestelmät

Mixedbedjärjestelmät, or mixed-bed systems, are a type of water purification technology that utilizes a mixture of ion-exchange resins to remove ionic impurities from water. These systems typically contain both cation and anion exchange resins in a single vessel, allowing for simultaneous removal of positively and negatively charged ions.

The primary function of mixed-bed systems is to achieve a very high degree of demineralization, producing ultrapure water. This is essential in applications where even trace amounts of dissolved salts can be detrimental, such as in the semiconductor industry, pharmaceutical manufacturing, and power generation. The cation exchange resin exchanges its hydrogen ions (H+) for positively charged cations in the water (e.g., sodium, calcium, magnesium), while the anion exchange resin exchanges its hydroxide ions (OH-) for negatively charged anions (e.g., chloride, sulfate, silica). The H+ and OH- ions then combine to form water.

The regeneration of mixed-bed resins is a crucial aspect of their operation. Unlike separate cation and anion exchangers, mixed beds are regenerated by separating the resins, typically through backwashing. The lighter anion resin floats to the top, allowing for separate regeneration with an acid (for anion resin) and a base (for cation resin). After regeneration, the resins are remixed to restore the system's purification capacity. The effectiveness of a mixed-bed system is often measured by its resistivity or conductivity, with higher resistivity and lower conductivity indicating purer water.