Can chelating resins be used in acidic conditions?
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This post was last edited by sunjl1981 on 2013-1-6 at 23:48. To improve the purity of chlorine gas, it is necessary to add acid to the slightly saline water. Can the point where the acid is added be located before the resin tower? Can chelating resins be used in acidic conditions? Let’s discuss this. # ， ， &
It seems that the original poster still doesn’t understand the principle of resin adsorption. Resins can only adsorb high-valency ions such as calcium and magnesium when they are in the Na-type state; therefore, they can only function in alkaline liquids. In acidic environments, the resins transform into the hydrogen-type form and can no longer adsorb high-valency ions like calcium and magnesium. Brackish water, acids, and resin columns should have no connection; resin columns are used to treat saturated saltwater. There is no need to discuss the issues with the building’s structure.
One of the optimal operating conditions for chelating resins is to maintain the pH of the saline solution between 8 and 10; it is clear that acidic saline solutions are not suitable for the operation of chelating resins, as these resins cannot be used in acidic conditions.
The operating conditions for different chelating resins vary; for example, those of the aminophosphoric acid type require a pH value of 9–11, while those of the iminodiacetic acid type need a pH value of 8.5–9.5, but this must be under alkaline conditions. If the brine entering the tower is acidic, it will convert the sodium-type resin into a hydrogen-type resin, causing it to lose its adsorption capacity; as a result, the quality of the brine will be severely compromised! !
I also think it won’t work; under acidic conditions, the resin uses hydrogen ions to displace sodium ions, which then flow out of the resin tower along with the saltwater. As a result, only the inactive light-type resin remains, and it is unable to remove calcium and magnesium from the saltwater. Therefore, after acid regeneration during resin regeneration, alkali regeneration is also required.
I fully agree with everyone’s views. I think since the regeneration process takes place under acidic conditions, during which the resin first turns into the H+ form and then into the sodium form, it means that the resin groups are more likely to bind with H+. Therefore, under acidic conditions, ions such as calcium and magnesium cannot be adsorbed by the resin. Thank you all. This discussion can now be closed; I’m not sure if the forum has such a function
It’s impossible; under acidic conditions, the resin is in the hydrogen form
In secondary brine purification applications, chelating resins cannot selectively adsorb calcium and magnesium ions under acidic conditions； However, for other applications, such as the adsorption of specific heavy metals in wastewater treatment, chelating resins can be used under acidic conditions.