DI Regeneration

[Garf]

I've been regenerating my DI resins for 10 years, but have found information that both GFO (chemical regen) and activated carbon (microwave regen) can also be regenerated. Has anyone tried it?

[Ace25]

Stumbled on those last year.. nope, seems like too much effort to me, but every person has to weigh their own cost to benefits. GFO regen works but the carbon regen I heard doesn't work, even in a kiln you can only clean so much of it, so if is last 7 days new, after regen only last 3 days because it can't cook out/unclog all the pores.

[CHOMPERS]

Can you post the links you have? I'm interested in regenerating all three. I had found a teacher that was begging for everyones used carbon, so it occurred to me that there must be a regeneration procedure but didn't find anything. Just recently, I found a proceedure for the GFO.

[CHOMPERS]

http://www.advancedaquarist.com/2010/10/chemistry

http://www.alibaba.com/product-free/112871128/Phospha_Guard_RE_CYCLE.html

[CHOMPERS]

http://alcoholpurification.com/recycling-activated-carbon/

I found this by searching "activated carbon recycling" rather than "regeneration".

[Garf]

Here's how I regenerate DI resin;

You need a few things first. Spent mixed bed resin, Hydrochloric Acid 16%, Sodium Hydroxide 16%'. Couple of jugs, old spoon, 20 ltrs RO (preferably RODI - the cleaner the better).


http://i1269.photobucket.com/albums/jj597/Garf1971/9637b4ff62dcad4d031506a094c2a2f6.jpg


First pour in SODIUM HYDROXIDE into the spent resin. This acts as a separating agent and a regenerant for the ANION RESIN.


http://i1269.photobucket.com/albums/jj597/Garf1971/121b32b4e1136f4e42e7e95189df6eb5.jpg


Stir the resins with an old metal spoon for a few seconds and put the container out of the way for an hour or so (you do not want to accidentally spill or splash these chemicals, they are sufficiently strong to cause real damage). You will notice that the two types of resins (CATION and ANION) separate, with the CATION at the bottom whilst the ANION floats to the top as regeneration is underway.


http://i1269.photobucket.com/albums/jj597/Garf1971/014e30df3e3294c0494be9479bf0a521.jpg


After a further small stir, leave it for ten minutes or so then pour off the ANION resin into another container slowly (try not to get the CATION into the ANION). You should end up with two containers (pale one ANION, dark one CATION).


http://i1269.photobucket.com/albums/jj597/Garf1971/32ac1a9bd0d6b84590e357f5fef22510.jpghttp://i1269.photobucket.com/albums/jj597/Garf1971/30d84deb950eb2e7508d834b0f9eebf7.jpg


The pale one is now regenerating (stir every 30 minutes) in the SODIUM HYDROXIDE that was used to separate the resins. The CATION requires a few extra steps though.
1). Rinse the CATION (dark one) with tap water to remove all traces of Sodium Hydroxide (fill the jug give it a stir, empty the water, then repeat about 10 times)
2). Add HYDROCHLORIC ACID to the CATION RESIN (dark one)
3). Put container somewhere safe and stir it every 30 minutes, for a couple of hours.


Now the resins have regenerated, rinse each one with RO or RODI (you can use tap water but this drastically reduces the life of the newly regenerated resins). I suggest using about 10 litres to rinse each resin (filling the jug, quick stir then ditching the water [ x10ish]) works best (the anion needs more water in so that the resin sinks. Each subsequent rinse becomes easier as the resin sinks faster with each rinse).


Now recombine the two recharged resins and stir thoroughly so the beads are well and truly mixed together and your ready to reload the resin chamber.


Run 10 litres of RO through the chamber whilst connected to the RO unit and discard. Job done. Sounds more complicated than it is, after a few regenerations it takes next to no time, as the majority of the time is just waiting for the regenerants to do there job.

[Garf]

GFO regeneration test.


1 litre of 1M (ish) sodium hydroxide solution (150mls 16% NaOH in 1 litre RODI), exhausted GFO. Leave the regenerant to replace phosphate ions with hyroxyl ions on the binding sites of the GFO is the first stage. This takes 3 days with an occassional gentle mix.


http://i1269.photobucket.com/albums/jj597/Garf1971/16abc6c9d71643fd2432d186607a17f9.jpg


After 3 days I will dilute the regenerant (1:100) so that I can test for phosphate presence, therefore indicating its effectiveness. Then I need to rinse the GFO.

[Garf]

Tested the regenerant (used 4.5 litres in total), took samples from each 1.5 litre batch and averaged the reading after neutralisation with a few mls of HCL.


http://i1269.photobucket.com/albums/jj597/Garf1971/42c10f73605f807ff50bfb07338143ec.jpg


Got a reading of 1.1ppm (diluted by 200), so 220ppm in 4.5ltrs is 2.2ppm in a 450 litre tank from 250grms of GFO. So now this regenerated GFO is capable of removing another 2.2ppm (450 ltr tank), over time. The regenerated GFO shows no to little degradation.


All that's needed now is a bloody good rinse in lots of RODI, as described in the above link, and it's done, almost free of cost. Gonna rinse slowly, over next few days with about 20ltrs RODI to be sure, then test it.

[Garf]

Returned the GFO to the tank, pH remained stable. Conclusion, it works.

Next to test the CARBON regeneration as linked by Chompers, thanks. There is also a microwave version which I'll get around to sooner or later.

[Garf]

Found a patent that makes lots of sense for activated carbon regeneration, sodium hydroxide (1 to 4%), ethanol (10 to 40%) remainder water, then soaked and boiled for 6 to 24hrs (more boiling, the better the results).
http://www.freepatentsonline.com/6423657.html

[Floyd R Turbo]

Geez. Sounds like a PITA. Unless you're regenerating a lot of carbon, isn't it just cheaper and easier to buy more?

[Ace25]

You also have to take into account even with all the work, and finding a Kiln to cook the carbon in afterwards (a critical step from what I have read other places), you get an extra 10-25% more use out of the spent carbon from doing all that work (meaning maybe a days worth of usage in our hobby). It just doesn't seem worth it to me. I have never seen or heard of anyone regenerating carbon to the point it is back to anywhere close to 100% efficiency. Heck, even Purigen I have noticed doesn't clean/regenerate back to 100% after first usage, at best I would say 80% and each time afterwards it goes down, which is why they say it only lasts for up to 10 regenerations/bleaching before it needs to be replaced.

Regenerating works for DI and GFO, I can see how both of those can save you money long term, but not carbon. I would love someone to prove me wrong but I am not holding by breath on that one.

[FrozenReef]

I have regened DI years ago. I have a stockpile ( entire Oceanic 5g salt bucket ) full of it. In our local club we are planning a regen party to do on a large scale and make a day of it. Will let you know how it goes.

We do similar parties several times a year and make a big vat of homemade fish food. That works well and always has a good turnout.

Will see if people have to stock piling the resins for the winter for the DI party late spring early summer.

[kaskiles]

Hey, maybe you can regen the GAC with an ozone generator:
http://www.ncbi.nlm.nih.gov/pubmed/15087197

[Floyd R Turbo]

I have regened DI years ago. I have a stockpile ( entire Oceanic 5g salt bucket ) full of it. In our local club we are planning a regen party to do on a large scale and make a day of it. Will let you know how it goes.

We do similar parties several times a year and make a big vat of homemade fish food. That works well and always has a good turnout.

Will see if people have to stock piling the resins for the winter for the DI party late spring early summer.

LOL I never thought of doing a DIY DI Regen event, I've hosted the DIY Food event twice and organized it 3 times total, that's one heck of an undertaking when you are making enough food to fill up a 5 gallon bucket!

[alum]

http://i1269.photobucket.com/albums/jj597/Garf1971/9637b4ff62dcad4d031506a094c2a2f6.jpg

I bough RO/DI resin, but my DI resin anion and kation already mixed in 1 tube.
Q: can I regenerate all anion kation all together in NaOH.. then HCl in it ?

[Garf]

Gotta follow the steps from post 6, you can't regenerate them without separating them first.

[Floyd R Turbo]

Go back to post #6. The two will separate during the regen process.

[alum]

Oh sorry I did not read it.....

then it can be done for me.... ok thanks.

[alum]

I ever read GFO can be regenerate too, but only iron base only... can not work for alumunium base...
have you ever read that too ?

[Garf]

I ever read GFO can be regenerate too, but only iron base only... can not work for alumunium base...
have you ever read that too ?

Back to posts 7 and 8 alum ;)

[Ace25]

I would not attempt to regenerate aluminum based phosphate remover (Phosguard).


Aluminum oxide can be partially regenerated by using sodium hydroxide. The principal behind this regeneration is that at pH levels below 8-8.5 aluminum oxide particles has a positive surface charge and can thus take up phosphate ions To release the phosphate, the pH level is increased by the addition of sodium hydroxide.

However, the solubility of the aluminum oxide increases with increasing pH level. Therefore, regeneration with a too strong sodium hydroxide solution gives loss of ion exchange resins. The concentration of the sodium hydroxide solution must thus adjusted to give a maximum phosphate release without a too large loss of ion exchange resins. Typical industrial process includes activation of aluminum oxide at 600 °C and usage of sodium hydroxide for the regeneration.

Due to the extreme caustic and hazardous nature of sodium hydroxide and the extreme temperature required, it is not recommended for any home user to regenerate aluminum oxide.

[Garf]

I would not attempt to regenerate aluminum based phosphate remover (Phosguard).

Nope, me neither. GFO only, ie Ferric (iron) Oxide.

[alum]

Back to posts 7 and 8 alum ;)

Op! miss again :D