The principle of water purification using workshop ion exchange method is based on the exchangeability between various ions in resin and natural water. H-type cation exchange resin, in which the exchange groups can exchange with various cations in the raw water, allowing equal cations in natural water to bind to the resin and enter the water, thus removing metal cation impurities from the water. When the raw water passes through an anion exchange resin, the exchangeable groups in the exchange group will undergo a neutralization reaction, resulting in high-purity deionized water.

离子交换法处理原水的工艺一般可采用阳床、阴床、混合床的组合形式，混合床为阴阳树脂以一定比例混合组成。大生产时为减轻阴树脂的负担，常在阳床后加脱气塔，除去二氧化碳，树脂使用一段时间后，需再生或更换。

The process of treating raw water using ion exchange method can generally adopt a combination of cation bed, anion bed, and mixed bed. The mixed bed is composed of anion and cation resins mixed in a certain proportion. In order to reduce the burden of anion resin during large-scale production, a degassing tower is often added after the cation bed to remove carbon dioxide. After a period of use, the resin needs to be regenerated or replaced.

电渗析法是在外加电场作用下，利用离子定向迁移及交换膜的选择透过性而设计的，由于阳膜荷负电，排斥阴离子，允许溶液中的阳离子通过，并使其向阴极运动。电渗析法较离子交换法经济、节约酸碱，但制得的水纯度不高，比电阻较低，一般在当原水含盐量高达3000mg/L时，用离子交换法制备纯化水时树脂会很快老化，故此时将电渗析法与离子交换法结合应用来制备纯化水较适合。

The electrodialysis method is designed by utilizing the directional migration of ions and the selective permeability of the exchange membrane under the action of an external electric field. Due to the negative charge on the cation membrane, it repels anions, allows cations in the solution to pass through, and causes them to move towards the cathode. The electrodialysis method is more economical and saves acid and alkali compared to the ion exchange method, but the purity of the water produced is not high and the specific resistance is low. Generally, when the salt content of the raw water reaches 3000mg/L, the resin will quickly age when using the ion exchange method to prepare purified water. Therefore, combining the electrodialysis method with the ion exchange method is more suitable for preparing purified water.

反渗透装置是靠外界压力使原水中的水通过半透膜，而杂质被膜阻挡下来，得到纯化水的一种操作，原水中的杂质浓度将越来越高车间厂房反渗透装置与一般微孔膜过滤装置结构一样，只是由于它需要较高的压力（一般在2.5-7MPa),所以结构强度要求高。由于水透过膜的速率较低，故一般反渗透装置中单位体积的膜面积要大，工业生产使用较多的反渗透装置采用的是螺旋卷绕式及中空纤维式。

Reverse osmosis device is an operation that uses external pressure to make the water in the raw water pass through a semi permeable membrane, and impurities are blocked by the membrane to obtain purified water. The concentration of impurities in the raw water will increase. The structure of the reverse osmosis device in the workshop building is the same as that of ordinary microporous membrane filtration devices, but it requires high pressure (usually 2.5-7MPa), so the structural strength requirement is high. Due to the low rate of water penetration through the membrane, the membrane area per unit volume in general reverse osmosis devices is larger. The reverse osmosis devices commonly used in industrial production are spiral wound and hollow fiber.

反渗透法制纯水时可采用适当的设计来强化系统的控制功能，改善系统的可靠性、出水的质量和系统的处理能力，例如采用“多级串联”设计，可以提高水的质量；采用“多级并联”设计，可以提高水的产量。

When using reverse osmosis method for pure water, appropriate design can be adopted to strengthen the control function of the system, improve the reliability of the system, the quality of the effluent, and the processing capacity of the system. For example, using a "multi-stage series" design can improve the quality of the water; Adopting a "multi-level parallel" design can increase water production.