Ion Exchange Systems and their Role in Water Softening
Most efforts to purify water and other liquids involve mechanical methods such as sedimentation and filtration. These techniques are used mainly to remove dirt. However, they can be adapted to separate any insoluble chemicals present in the untreated source. In the latter case, the objective of the exercise is sometimes not purification but recovering a valuable substance or something that might be reusable. However, removing dissolved chemicals poses more of a problem for which ion exchange systems can often be the best solution.
The name given to this technology provides a clue to how it works. It suggests that the process involves swapping something undesirable that forms ions when dissolved in water for a harmless alternative. In contrast to conventional filtration methods, the underlying principle is electrochemical rather than mechanical. There are numerous applications for this technology, and one of the most common is the treatment of hard water. The affected water contains a high concentration of calcium and magnesium salts that can prove troublesome. Fortunately, particle exchange systems offer a safe, convenient, and effective way to overcome this annoying phenomenon.
In the home, the salts in hard water reduce lather formation by soaps and detergents and cause scale to build up in kettles, dishwashers, and washing machines, reducing their performance and lifespan. In industry, hard water can take its toll on boilers, pumps, and pipelines. However, passing hard water through a bed of suitably charged resin can remove the offending ions and end those problems. So, how exactly do these exchange systems work?
For this purpose, tiny beads of a resinous polymer with a structure that includes fixed negative ions are treated with brine, allowing a positively charged sodium ion to attach to each immovable negative ion, rather like the opposing poles of magnets. When hard water passes over the treated resin beads, the strongly positive calcium and magnesium particles displace the weakly charged sodium ions to become firmly embedded in the resin. Because sodium salts are much more soluble than those of the replaced elements, they will not precipitate and cause problems.
These exchange systems have many other uses. By preparing the resins appropriately, they can be induced to remove either anions, cations, or both. Some typical applications of this technology include removing specific elements like arsenic from water, recovering valuable metals from wastewater, and preparing ultra-pure water for use in medical laboratories and the pharmaceutical and food and beverage industries.
Contact the experts at WaterIcon for more in-depth advice on filtration technology in general or to purchase high-quality equipment and reagents for use in ion exchange systems.