How Is Ion Exchange Resin Preserved

Resin pretreatment

Because in the process of synthetic resin, the surface and void of the resin are mixed with low molecular and some inorganic impurities (such as copper, iron, etc.), molecular monomer substances, and pore-causing agents, etc., so before the resin is officially put into operation, these impurities must be removed, otherwise it will pollute the resin in various ways during use. In particular, it should be pointed out that in the wastewater containing chromium, because chromic acid is an oxidizing agent, such as copper and iron in the resin, it has a catalytic oxidation effect, thereby speeding up the oxidation of the resin. The pretreatment method is as follows:

1. Wash in hot water

The new resin to be used is washed repeatedly with hot water. Yang resin can be used in hot water of 70 ~ 80℃, Yin resin (especially strong alkali Yin resin) has poor heat resistance, and can be used in hot water of 50 ~ 60℃. When starting to soak, change the water every 15 minutes or so, if it is not stirred when washing, change the water 4-5 times, you can change the water every 30 minutes or so, a total of 7 to 8 times, soak until the washing water is not brown and the foam is very little.

2. acid, alkali treatment

The resin is washed in hot water and then filled into the column and treated with acid and alkali. Positive resin with 1mol/1HCL slowly flow through the resin layer, the amount is about 2 to 3 times the volume of the resin, about 2 hours to finish the flow, slightly washed with water, and then with 1mol/1NaOH flow through the resin layer, the amount and flow rate are the same as before. After the alkali flow is finished, the resin is washed with water until the effluent ph9 is about, and then 1mol/1HCL or 0.5mol/1H2SO4 is used to convert the resin into H+ type, the dosage is 3-4 times the volume of the resin, and the flow rate is the same as before. After the acid flow is finished, wash with water until the water is above ph6, you can put into operation.

Resin care

In the process of using the resin, the pollution of suspended matter, organic matter and oil should be prevented, and the violent oxidation of some wastewater on the resin should be prevented. Therefore, heavy metal ions should be removed before the acid oxidation wastewater enters the negative resin to prevent the catalytic effect of heavy metals on the resin. After each operation of the equipment, the waste water in the exchange column should be discharged back to the waste water tank and soaked in tap water or purified water instead. The resin should be regenerated in time after saturation, and should not be soaked in the stock solution for a long time after regeneration, and should be washed in time.

Resin activation

Whether it is positive resin or negative resin, when used for several cycles, the exchange capacity will decrease. On the one hand, due to incomplete regeneration, a certain amount of unregenerated ions on the resin gradually accumulate, affecting the normal exchange; On the other hand, for example, H2CrO4 and H2Cr2O7 in the wastewater containing chromium have oxidation effects on the resin, so that more and more Cr3+ in the resin affects the normal work of the resin. Therefore, when the resin capacity has a significant decline trend, the activation of the resin should be carried out.

1. the activation of anion ion exchange resin

The activation measures of negative resin should vary according to the wastewater being treated. There are some successful experiences on negative resin activation in treating wastewater containing chromium in China. The principle of operation is as follows: After normal regeneration of Yin resin, soak in 2-2.5mol //1H2SO4 solution, and then add NaHSO3 under slow stirring to reduce Cr6+ on the resin to Cr3+. The resin is soaked in the above solution for one day and night, and then washed with clean water. The above process is repeated for 1-2 words, and Cr6+ and Cr3+ in the resin can be removed, and then transformed with NaOH for use.

2. Activation of cation ion exchange resin

The main purpose of positive resin activation is to remove the heavy metal ions accumulated on the resin, especially those valant cations with strong binding force with the resin, such as Fe3+, Cr3+, etc. It can be activated in the body, the amount of activation liquid is 2 times the volume of resin, and the hydrochloric acid configuration with a concentration of 3.0mol/1 is used to pass through the resin layer at the regeneration flow rate, and then the resin is soaked in sulfuric acid solution with 1 ~ 2 times the volume of resin and a concentration of 2.0 ~ 2.5mol/1 for one day and night (at least 8 hours). Cr3+ and other heavy metal ions are basically removed, and the resin can be used after washing.