In the process of using resin, the pollution of suspended matter, organic matter and oil should be avoided, and the severe oxidation of some wastewater on resin should be avoided. Therefore, heavy metal ions should be removed before acid oxidation wastewater enters anion resin to avoid the catalysis of heavy metals on resin. After each equipment is running, the wastewater in the AC column shall be discharged back to the waste water tank, and then soaked in tap water or purified water instead. After the resin is full, it is not suitable to soak and park in the original solution for a long time after it is full, and it should be washed in time.
Whether it is cation resin or anion resin, when used for several cycles, the AC capacity will decrease. On the one hand, the reason for the decrease of capacity is that the selection is incomplete, and the amount of ions on the resin that is not down is gradually accumulated, which affects the normal exchange; On the other hand, H2CrO4 and H2Cr2O7 in chromium containing wastewater have oxidation effect on the resin, which makes cr3+ more and more in the resin, which affects the normal operation of the resin. Therefore, when the resin capacity has a significant decline, the resin activation should be carried out.
The activation method of anion resin should be different according to the wastewater. Domestic experience in the treatment of chromium containing wastewater by anion resin activation is relatively successful. The principle operation is as follows: soak the anion resin in 2-2.5mol / 1h2so4 solution after normal, then participate in NaHSO3 under slow mixing, and reduce cr6+ on the resin to cr3+. The resin is soaked in the above solution for one day and night, then washed with clear water. Repeat the above process for 1-2 words, and then remove cr6+ and cr3+ in the resin, and then use NaOH to transform for use.
The main purpose of cation activation is to remove heavy metal ions accumulated on the resin, especially those high priced cations with strong binding force with resin, such as fe3+, cr3+. It can be activated in vivo. The amount of activated liquid is twice the volume of resin. Hydrochloric acid equipment with a concentration of 3.0mol/1 is used. The resin layer is soaked with a flow rate of 1-2 times the volume of resin, and the concentration is 2.0-2.5mol/1 sulfuric acid solution. It takes one day and a day (at least 8 hours). The fe3+, cr3+ and other heavy metal ions in the resin are basically removed. After rinsing, the resin can be used.
Post time: Jun-09-2021