Ion exchanger for water softening

Too much lime In water, water makes it hard. Very hard and calcareous water can leave unsightly marks on faucets, irritate sensitive skin and permanently damage electronic devices. To counteract this, water softening is useful. The ion exchanger is one of various ways to soften water, i.e. to reduce the amount of lime in it. Read here about the advantages and disadvantages of this method and how it works.

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Water science: ions in water

The water quality in Germany is generally very good, because the water is extensively treated using a special process so that it is of drinking water quality in the end and can flow through our pipes. In this process, the water is produced by harmful bacteria and frees substances so that almost pure and healthy water is produced. However, dissolved substances may still be present in the water.

Our tap water contains minerals such as calcium, sodium and magnesium. These minerals, for example, are dissolved substances in water and belong to the electrical charge carriers, the so-called ions. The positively charged ions are called cations, the negatively charged ions are called anions. Cations include the minerals calcium and magnesium. A large amount of these two substances is responsible for a high proportion of lime in the water and leads to increased calcium formation. This information is important to understand the process and functioning of a ion exchanger to understand.

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What is an ion exchanger?

Ion exchangers are used to make water softer by removing electrical charge carriers (ions) from the water.

But what exactly is an ion exchanger? To answer this question, you need a bit of chemical knowledge: Salts, acids and bases are made up of ions. These substances break down more or less when they are dissolved in water. Ion exchangers have the ability to bind certain ions from solutions and replace them with other ions of the same charge.

A distinction is made between cation and anion exchangers in terms of the charge that is to be filtered. If an ion exchanger is used to soften water, the calcium and magnesium cations are removed from the water, as they are responsible for calcium formation in the water. These cations are then replaced by sodium ions. In addition, chloride is released into the waste water in this process. That is why ion exchangers regularly require sodium chloride. The ion exchangers themselves consist of synthetic resins or polymers (plastics), which serve as a carrier medium for the exchange of ions.

Ion exchanger: How it works explained step by step

The ions give water certain properties, such as electrical conductivity, which water hardness or even the pH value. The solubility of these substances is significantly influenced by their quantity in water and water temperature. Ion exchangers treat water in a targeted manner by removing the electrical charge carriers or exchanging them with other ions.

The ion exchange process works as follows:

1. Step: A special solution flows through the ion exchanger. There are either positively or negatively charged ions in this solution. In domestic use, a solution of sodium chloride is often used for this purpose. This process is called “regeneration.”
2. Step: If tap water now flows into the ion exchanger, the ions to be removed (calcium and magnesium) from the tap water stick to the ion exchanger resin in order to be replaced with the sodium ions of the previous solution.
3. Step: The calcium and magnesium ions get “stuck” in the exchange resin. Sodium is released into tap water.
4. Step: If there are no more sodium ions left, the ion exchanger is considered “exhausted.” At this point, the calcium, magnesium and chloride solution remaining in the ion exchanger is flushed into the waste water. That is why ion exchangers also require a waste water connection.
5. Step: Next, a new “regeneration” starts and the process starts again at step 1.