Regenerating Soda lime for CO2 Scrubbing

[atoll]

Hi, RandyI wonder if you would be so kind to help with the following question?

I have a Marine Scourses CO2 scrubber using Soda lime pellets to remove CO2. I use the following media here. https://www.medistock.co.uk/products/soda-lime-can-5-litre-spherasorb
Do you know if there is a simple way to regenerate the media say in the oven or using a microwave for instance?
Thanks.

 

[Andy G]

Eager to hear if there's a way.

 

[Randy Holmes-Farley]

Hi, RandyI wonder if you would be so kind to help with the following question?

I have a Marine Scourses CO2 scrubber using Soda lime pellets to remove CO2. I use the following media here. https://www.medistock.co.uk/products/soda-lime-can-5-litre-spherasorb
Do you know if there is a simple way to regenerate the media say in the oven or using a microwave for instance?
Thanks.

I don't believe there's any way to regenerate significant capacity:

https://www.shearwater.com/wp-content/uploads/2012/08/Sodasorb_Manual.pdf

Color Reversion Color reversion is the phrase used to describe the reversion of exhausted Sodasorb absorbent from purple to white when allowed to sit idle for a few hours or more. In the past, the term regeneration of soda lime has been incorrectly used to describe this process. This color reversion is the result of subsurface calcium hydroxide regenerating active hydroxide at the surface of the granule. This alters the pH of the surface and, consequently, causes the indicator dye to revert back to white, even though the Sodasorb may be near exhaustion. Soda lime does not regenerate. Instead, there has been a reversion of the indicator dye from purple to white. Although there may be some additional carbon dioxide uptake due to the migration of these hydroxides, the absorptive capacity of soda lime, previously saturated with CO2, is minimal and should be relied upon, even if the color of the granules has reverted back to white. It is important, therefore, for operating room personnel to determine how much absorptive capacity is left in Sodasorb absorbent immediately at the end of a surgical procedure. Visual inspection at the end of the procedure will yield an approximate estimate of the remaining absorptive capacity. If it is purple a quarter of the way down, the Sodasorb is exhausted by approximately 25%, half way down equals approximately 50%, and so on.

 

[atoll]

Thanks, Randy, much appreciated. I guess it's not so expensive to discard and replace after all. I was hoping, however, the media would stay active 100% until the colour of all the beads had changed. I would be loathed to discard all the media with just around 50% having changed colour.

 

[W@tchm@n]

Bump..
Thinking about using thus soda lime from tgr same place... How have u found it, would you recommend?

Thanks

Hi, RandyI wonder if you would be so kind to help with the following question?

I have a Marine Scourses CO2 scrubber using Soda lime pellets to remove CO2. I use the following media here. https://www.medistock.co.uk/products/soda-lime-can-5-litre-spherasorb
Do you know if there is a simple way to regenerate the media say in the oven or using a microwave for instance?
Thanks.

 

[atoll]

Bump..
Thinking about using thus soda lime from tgr same place... How have u found it, would you recommend?

Thanks

Yep does the job fine and makes around a +03/04 increase in PH

 

[W@tchm@n]

Yep does the job fine and makes around a +03/04 increase in PH

Thanks mate...
What are u running this in.. As in what type of cannister /reactor?
Also, how often do u replace media.. I know this all depends on the factors of the room the tank is on etc.. But. Just trying to get some ideas.

Thanks again

 

[atoll]

Thanks mate...
What are u running this in.. As in what type of cannister /reactor?
Also, how often do u replace media.. I know this all depends on the factors of the room the tank is on etc.. But. Just trying to get some ideas.

Thanks again

As above, I have a Marine Scourses CO2 scrubber connected to the air intake of my skimmer. This lasts me about a month before it needs changing.

 

[W@tchm@n]

Cool...
Thanks mate..

 

[kecked]

I see this is an old thread but wanted to ask. If you simply strip the CO2 with media for the air feeding your skimmer, would not the exchange rate of the top surface be large enough that it might make no difference? IE you would not see a huge drop in CO2 effects or is the rate from the skimmer dramatically larger than then ambient diffusion on the surface. The surface area of the skimmer bubbles must be an order of magnitude or more larger than the top surface of the water. Think I just answered my own question.

 

[Randy Holmes-Farley]

I see this is an old thread but wanted to ask. If you simply strip the CO2 with media for the air feeding your skimmer, would not the exchange rate of the top surface be large enough that it might make no difference? IE you would not see a huge drop in CO2 effects or is the rate from the skimmer dramatically larger than then ambient diffusion on the surface. The surface area of the skimmer bubbles must be an order of magnitude or more larger than the top surface of the water. Think I just answered my own question.

Surface exchange can limit the effectiveness, yes. It is not enough prevent the effect for most people, however.

 

[kecked]

wonder if tech like this might be more effective. Strip everything out but the oxygen. Was thinking those membranes for nitrogen separation. The waste gas stream then feeding this. Might be scaleable for a fishtank. Now you put straight or say 50% oxygen into the skimmer. That should increase O2 in the water, keep CO2 out, and maybe even increase efficiency since it might oxidize some organics. Not sure if too much of a good thing would be a problem but I think the flow and mixing should prevent a giant spike in O2. Just don't know if the membranes exclude the CO2. O2 Kinetic is 346 and CO2 is 330. Different but not by much. PDMS Zeolite? Not sure but it sure would eliminate a lot of media.

https://www.oxygenconcentrator.shop/products/portable-oxygen-concentrator-tip-9?variant=19764801241147&utm_medium=cpc&utm_source=google&utm_campaign=Google Shopping&gclid=Cj0KCQjwrJ7nBRD5ARIsAATMxsvlGKC8cyAbezOH7V0F9oJOuhlM7w0Nc6NTwKlavS-jdJrpVWRtiXMaAqunEALw_wcB

Should stick these on cars to knock down nox and sox https://patents.google.com/patent/US20090223494

 

[Randy Holmes-Farley]

wonder if tech like this might be more effective. Strip everything out but the oxygen. Was thinking those membranes for nitrogen separation. The waste gas stream then feeding this. Might be scaleable for a fishtank. Now you put straight or say 50% oxygen into the skimmer. That should increase O2 in the water, keep CO2 out, and maybe even increase efficiency since it might oxidize some organics. Not sure if too much of a good thing would be a problem but I think the flow and mixing should prevent a giant spike in O2. Just don't know if the membranes exclude the CO2. O2 Kinetic is 346 and CO2 is 330. Different but not by much. PDMS Zeolite? Not sure but it sure would eliminate a lot of media.

https://www.oxygenconcentrator.shop/products/portable-oxygen-concentrator-tip-9?variant=19764801241147&utm_medium=cpc&utm_source=google&utm_campaign=Google Shopping&gclid=Cj0KCQjwrJ7nBRD5ARIsAATMxsvlGKC8cyAbezOH7V0F9oJOuhlM7w0Nc6NTwKlavS-jdJrpVWRtiXMaAqunEALw_wcB

Should stick these on cars to knock down nox and sox https://patents.google.com/patent/US20090223494

My concern would be excessively high O2. It might rise several fold over normal saturation.

 

[kecked]

And fire. We could do it safe but less educated might use it in too small a space. Well guess it could be back blended with the purified nitrogen stream so the net result was neutral to the room but the co2 got stripped from the skimmer stream.

I think I’ll try it. Not that expensive. My actual solution was a lot of plants. I mean lots. I have a greenhouse of coffee trees, orchids, jasmine, and elephant ears..... guess what they use o2 at night and make co2! It made it worse.

Edit: if I use 90% enrichment and say it does not remove co2 and ambient is 450ppm co2. Residual is 45ppm CO2. Blend with regular air 80% enriched 20%. I think roughly the decrease in CO2 is only about 10% to 400ppm. Lot of work for little gain. Guess you could use nitrogen gas but that’s a hassle and anew disposable. Bah can’t win.

Hey wanted to say thank you. You done so much for us. I rarely see anyone thank you.

 

[Gribbliest]

@Randy Holmes-Farley
Sorry for reviving an old thread. As above I really appreciate your feedback on all things Reef Chemistry related!!!

My understanding, is that once the CO2 Media is spent, you are left with what's effectively Calcium Carbonate. Is this correct?

If so, if I were to use a Calcium Hydroxide without the pH dye, could there be a secondary use for the media once spent - to maybe use in a calcium reactor or some other method, to provide that Calcium Carbonate back to the system for the corals to utilise?

 

[Randy Holmes-Farley]

@Randy Holmes-Farley
Sorry for reviving an old thread. As above I really appreciate your feedback on all things Reef Chemistry related!!!

My understanding, is that once the CO2 Media is spent, you are left with what's effectively Calcium Carbonate. Is this correct?

If so, if I were to use a Calcium Hydroxide without the pH dye, could there be a secondary use for the media once spent - to maybe use in a calcium reactor or some other method, to provide that Calcium Carbonate back to the system for the corals to utilise?

Fully spent soda lime will contain sodium carbonate, sodium bicarbonate, and calcium carbonate.

I would not put that into a reactor as it will boost alkalinity excessively relative to calcium.

 

[Gribbliest]

Thanks Randy,

Thought I'd ask, as I hate throwing things out that may have a use!