I’m encountering severe overheating when using 32% nitric acid to adsorb organic substances with resin and then applying an alkali for desorption. What are some good solutions?
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I’m encountering severe overheating when using 32% nitric acid to adsorb organic substances with resin and then applying an alkali for desorption. What are some good solutions?
The concentration of nitric acid remaining in the resin gaps is too high, leading to a vigorous neutralization reaction with the alkali and thereby overheating； There are two methods: 1. If draining the resin is no problem, the nitric acid contained in the resin can be drained first, and then it can be eluted with an alkali ； 2. It is also possible to pass nitric acid through first, rinse the resin with water to reduce the concentration of nitric acid inside, and then apply an alkali.
In terms of engineering, even after washing with water and then applying alkali, it still doesn’t work; the process of draining out the resin is not feasible
Intense heat release leads to overheating; in that case, wash it more often, or reduce the concentration of the alkali, as this will result in a larger volume.
First wash with water, then neutralize with alkali; the washing water is used to prepare the alkali
Should caustic soda be used for desorption, or can soda ash be used instead? Washing with water before desorption can reduce nitric acid residues, but what is trapped within the resin’s adsorption pores is not easy to wash out
Set up a circulating stream with a high circulation ratio!
Industrial wastewater containing basic organic compounds has its pH adjusted to the pKb of those organic compounds at 25°C, followed by filtration to remove the suspended solids. The resulting filtrate is passed through an adsorption tower filled with basic composite functional adsorption resin; adsorption is stopped once the leakage point is reached, and dilute hydrochloric acid or dilute sulfuric acid is used as a desorbent to release the basic composite functional adsorption resin. This invention does not affect the adsorption performance, but enhances the regeneration capacity of the adsorption resin, thereby reducing the amount of desorbent used and lowering the desorption temperature
Personally, I think it’s because the acid cannot be cleaned thoroughly by washing alone; one can use a rinsing step after washing with acid, and by testing the acid concentration after this rinsing, the number of rinsing times can be determined