Ion exchange resins are specialized materials used to remove unwanted ions from liquids, particularly in water treatment processes. They consist of small beads made from organic polymers that can exchange specific ions with those in the surrounding solution. This process helps purify water by replacing harmful ions, such as calcium or magnesium, with more desirable ones, like sodium. These resins are commonly used in various applications, including water softening, demineralization, and chemical processing. They come in two main types: cation exchange resins, which target positively charged ions, and anion exchange resins, which target negatively charged ions.