Regenerating ion exchange resin

[skyshrimp]

Here is video showing how to regenerate and seperate mixed bead resin with hydrochloric acid and sodium hydroxide.



There is a product called Nitra-Zorb which I assume is a anionic ion exchange resin and some kind of zeolite. They advise customers to recharge it with sodium chloride.

Mixed bead ion exchange resins are preloaded with hydroxide and hydronium.

From what I understand from the video, the cationic beads need to be washed with hydrochloric acid. The chloride pulls the metals off and they are replaced with hydronium again.

The anionic beads need to be washed with sodium hydroxide, The sodium pulls the negatively charged molecules off the beads and they are replaced with hydroxide again.

There is a product on the market called Nitra-Zorb which is for aquarium use which removes negatively charged molecules like NO3 and PO4 etc. I think it's a mixture of anionic beads and zeolites. https://www.apifishcare.com/product/nitra-zorb

They state that the product can be recharged with sodium chloride. This is what confuses me as I don't fully understand hydrolysis. If the media is saturated with chloride ions after the soak, how could it be used again in an aquarium? Doesn't chloride have a stronger electronegative charge than NO3?

Would it be best to use sodium hydroxide to recharge it? I'm assuming they can't advise people to handle strong bases so went with table salt, but I don't understand how it can be reused after being saturated with chloride instead of hydroxide.

 

[Nik_2213]

IIRC, from swapping weary cartridges on our lab's RO pre-conditioners, there's also a rinse phase to flush excess 'regeneration' chemicals...

 

[skyshrimp]

Sorry, I confused electronegative charge with negative charge. NO3 doesn't have an electronegative charge. It just has a negative charge of -1. (stupid meds...)

I've read that people usually use sodium chloride to regenerate mixed bead resin, but that will add sodium choride back to the treated water.