Why is weak resin relatively easy to regenerate?
The resin used for a period of time after ion exchange, adsorption of impurities is close to saturation, must carry on the regeneration treatment, chemical agent ion adsorption resin and other impurities was removed, so as to restore the original composition and performance. In practice, in order to reduce the cost of regeneration, it is necessary to appropriately control the dosage of regeneration agent, so that the performance of the resin can be restored to the most economical and reasonable regeneration level, and the recovery degree of the control performance is usually from 70 to 80%. If higher levels of regeneration are achieved, the regeneration dose will increase considerably, and the utilization of the recycled agent will decrease.The regeneration of the resin shall be based on the kind and characteristics of the resin, as well as the economy of the operation, and the proper regeneration agent and working conditions shall be chosen.The regeneration characteristics of resin are closely related to its type and structure. The regeneration of strong acid and strong alkaline resin is difficult. The regeneration dose is much higher than the theoretical value, while the weak acid or weak base resin is easy to regenerate, and the regeneration dose needs only a little more than the theoretical value. In addition, resins with large pass and low cross linking degree are easy to regenerate, while those with gel type and high crosslinking degree have longer regeneration reaction time.
Special regeneration treatmentThe resin with serious pollution, acid or alkaline salt solution such as repeated treatment with 10%NaCl alkali salt solution +1%NaOH dissolved organic matter, and 4%HCl or 10%NaOH were used and 1%HCl dissolved inorganic compounds, followed by 10%NaCl +1%NaOH, at about 70 DEG C.If the above treatment does not meet the requirements, the oxidation process can be used. After washing the resin with water, the sodium hypochlorite solution with a concentration of 0.5% is used to control the flow rate from 2 to 4BV/h, and the amount is 10 to 20BV. Then the water is washed by water and treated with salt water. It should be noted that oxidation treatment may lead to the bonding of macromolecules in the resin structure, resulting in degradation of the resin, swelling degree, easy to crack, so it is not suitable for use. 50 cycles are usually used before an oxidation treatment takes place. Because of the strong oxidation resistance of the chlorinated resin, the resin is treated with brine before it is oxidized and changed into chlorine, which can avoid the change of pH value in the treatment process and make the oxidation more stable.
Disposal of regenerated waste liquidThe sugar factory uses resin decolorization, resin regeneration waste liquid contains a large number of pigments and organic substances, the color is very deep. With the production of refined sugar sugar, every 100 tons of recycled waste sugar is about 6 ~ 9m3. It is also a difficult problem to be discharged (or recycled) after treatment.Bento has studied in detail the treatment of regeneration liquid by chemical methods, which can precipitate pigments and other organic compounds, remove impurities, recycle them, reduce emissions, and take full advantage of sodium chloride. Because the concentration of pigment regeneration in liquid ratio of juice is 10 times higher than the amount of liquid is small, no sugar viscosity, and can allow strong conditions such as strong alkali and high temperature and no need to worry about the decomposition of sugar, chemical processing more convenient. The regeneration liquid is added to the lime milk of 5 ~ 10% volume (the concentration is CaO100g/ L), heated to 60 DEG C and slightly stirred, and a large number of colored precipitates are precipitated. Add sodium carbonate or carbon dioxide, sodium phosphate or phosphoric acid, and maintain alkaline, can make more colored precipitate. The treated liquid, with a small amount of salt, can be returned to the primary recycling liquid for the resin, which is then regenerated with new brine.Treatment of waste liquid of various methods: using granular activated carbon adsorption, sodium hypochlorite, calcium hypochlorite, chlorine or ozone to oxidation, separation of organic compounds from it by ultrafiltration or reverse osmosis, or powdered resin etc.. Recently, Guimaraes and other studies have used microorganisms to degrade their colored products and achieve better results
