离子交换是指采用离子交换树脂，与水溶液中的各种离子之间发生等物质的可逆交换，从而使水质改善，而离子交换树脂的结构并不发生实质性变化的水处理方式。用来装载离子交换树脂的设备称为离子交换器。根据所装载的树脂种类不同，其去除的例子种类和实现的功能也不同。离子交换法是早期最常使用，最普及的水处理方法，无论是锅炉用水得软化，脱碱软化，除盐水，纯水，超纯水的设备，还是工业废水处理，重金属及贵重金属回收等场合均可采用的离子交换法来进行。离子交换设备是一种传统的、工艺成熟的脱盐处理设备，其原理是在一定条件下，依靠离子交换剂(树脂)所具有的某种离子和预处理水中同电性的离子相互交换而达到软化、除碱、除盐等功能。用于深度脱盐处理，产水电阻率动态可达到18MΩ·cm。
Ion exchange refers to the use of ion exchange resin, and a variety of ions in the water solution between the reversibility of material exchange, so as to improve the water quality, and the structure of ion exchange resin does not change substantially.The equipment used to load ion exchange resins is called an ion exchanger.Depending on the type of resin loaded, the types of examples removed and the functions implemented vary.Ion exchange method is the most commonly used and the most popular water treatment method in the early days, whether it is boiler water softening, alkali softening, demineralization, pure water, ultra-pure water equipment, or industrial wastewater treatment, heavy metals and precious metal recovery occasions can be used for ion exchange method.Ion exchange equipment is a traditional and mature desalination treatment equipment, its principle is that under certain conditions, the ion exchange agent (resin) has a certain ion and the pretreatment water with the same electrical ion exchange to achieve softening, alkali, salt and other functions.For deep desalting treatment, water resistivity can be up to 18 m dynamic Ω · cm.