Cautions for Cation Exchange Resin

　　1. Ion exchange resins contain certain moisture and should not be stored in the open air. During storage and transportation, they should be kept moist, avoid air-drying dehydration, and break up the resin. If the resin is dehydrated during storage, they should be soaked in concentrated salt water (10%) first, then gradually diluted. They should not be directly put into the water, so as to avoid rapid expansion and breakage of the resin.

　　2. In winter storage and transportation, we should adhere to the temperature environment of 5-40 C, avoid supercooling or overheating, and affect the quality. If there is no thermal insulation equipment in winter, we can store the resin in salt water. The concentration of salt water can be determined by temperature.

　　3. Ion exchange resins in industrial products often contain a small number of low-polymer and non-reactive monomers. They also contain inorganic impurities such as iron, lead and copper. When the resin touches water, acid, alkali or other solutions, the above-mentioned substances will be transferred into the solution, affecting the quality of the effluent water. Therefore, it is necessary to pretreat the new resin before use. Generally, water is used first to make the resin full of swelling. Then, the inorganic impurities (mainly iron compounds) can be removed with 4-5% dilute hydrochloric acid, and the organic impurities can be removed with 2-4% dilute sodium hydroxide solution and washed to near neutral. If it is used in pharmaceutical preparation, it must be soaked in ethanol.

　　4. In the application of resin, avoid touching with metal (such as iron, copper, etc.) oil pollution, organic molecular microorganisms, strong oxidizer, etc., so as to avoid ion exchange decreasing or even losing its function. Therefore, it is necessary to activate the resin irregularly according to the situation, and the activation method can be determined according to the pollution situation and conditions. In softening of ordinary anodic resin, the pollution of Fe can be easily leached with hydrochloric acid. The anion resin can be soaked or leached in 10% NaC1+2-5% NaOH mixed solution, soaked in 1% hydrogen peroxide solution for several minutes if necessary, and other treatment methods such as acid-base replacement, bleaching, alcohol treatment and various sterilization methods can also be used.

　　5. Pretreatment of new resins: Ion exchange resins in industrial products often contain a small number of oligomers and monomers that do not participate in the reaction, but also contain inorganic impurities such as iron, lead and copper. When the resin touches water, acid, alkali or other solutions, the above substances will be transferred into the solution, affecting the quality of the effluent. Therefore, it is necessary to pretreat the new resin before use. Generally, the resin is swelled by water, then the inorganic impurities (mainly iron compounds) can be removed by 4-5% dilute hydrochloric acid, and the organic impurities can be removed by 2-4% dilute sodium hydroxide solution and washed to near neutral.