C02 Scrubber by Solution

[Urville]

I like the idea of a C02 scrubber. I love that it is something easy to DIY which brings the cost down.

I'm not terribly fond of the cost of the media. I'd like to get that down even more, even over the 5 gallon bucket prices.

Then it occurs to me, I've seen this done in a school lab environment, I'm positive. So, I do some video watching and research. Several companies are using similar tech to offer climate change CO2 reclamation and removal.

In the experiment, essentially you mix a kalkwasser solution and bubble the ambient air through it to remove CO2 in the same way you use the soda lime pellets. You don't get a color change, but when you can get bulk buys of lime for rock bottom prices, you're dropping the bottom out of the cost of scrubbing C02 out of the air and using a reagent many of us already have or acquire regularly.

Additionally, with two chambers, ph metering, and the right solenoid you could set up rotating cylinders further minimizing maintenance impact.

My intent is to give this a try, by building the reactor and testing it on a friends tank since I lack access at this time to a controller/ph monitor.

 

[clsanchez77]

Not sure about CO2 scrubbing media costs but I am always for a better and cheaper mouse trap. The only flaw I see is getting a pH probe to work in the range of kalkwasser. Saturated kalkwasser is 12.6 or in that range and there are no pH calibration solutions in that range. I do suppose you could make your own...using saturated kalkwasser. At 25 degrees C, it is a known standard.

 

[Urville]

I should have been more clear. The PH probe would be part of a larger controller solution. When the kalwasser solution stopped absorbing CO2 as efficiently or at all, the ph would start swinging in the reef system. The system could detect this swing via probe and switch to the unused kalkwasser solution. This would give ample time to discard and prepare a new solution. I know right now many whom use the soda lime pellets with color changing reaction use a PH probe to determine when the media is depleted. I assume the CO2 absorbing ability depleted solution could not be used to dose KW.

 

[clsanchez77]

I should have been more clear. The PH probe would be part of a larger controller solution. When the kalwasser solution stopped absorbing CO2 as efficiently or at all, the ph would start swinging in the reef system. The system could detect this swing via probe and switch to the unused kalkwasser solution. This would give ample time to discard and prepare a new solution. I know right now many whom use the soda lime pellets with color changing reaction use a PH probe to determine when the media is depleted. I assume the CO2 absorbing ability depleted solution could not be used to dose KW.

Ok, that makes a lot more sense! Now, you can use a conductivity probe to monitor the kalkwasser saturation. As you scrub CO2, the kalkwasser will be converted to calcium carbonate and precipitate out. Once the Calcium Hydroxide is no longer saturated, the conductivity of the solution will rapidly drop. Supposedly the standard conductivity is 10.4, but mine hovers around 7.4. Im sure the difference is temperature related as my stand stays around 85 instead of 77, but Im not sure that accounts for all of it.

 

[Urville]

I'm doing some research and planning/preliminary experimentation. I plan to update as soon as I have something at least marginally viable. The idea would be that it is easy to build and inexpensive. Then I can test it and chart some figures on cost vs. effectiveness. No point if it cant beat common commercial soda lime solutions on cost and effectiveness.

 

[Justfbilly]

I have also been looking into a more cost effective medai to use for a CO2 scrubber. I stumbled upon a video where some kids did a science experiment using Cat Litter with Carbon to see if it would reduce the CO2. They used Alka Seltzer as the source of the CO2 and a very small amount of cat litter in a small peice of PVC pipe and then ran an air line into and out of the PVC tubing and checked the results with a lab grab CO2 tester and i was amazed that it dropped the amount of CO2? I am going to set up a scrubber and intall it on my 125 gallon reef to see if it works.

 

[clsanchez77]

Cat litter lol. I would have never guess. Was it a specific type? How would you know when its exhausted? I suppose the pH level will indicate it.

I am getting ready to run a closed loop outside for a small chiller and while I am at it I may run a fresh air line as well. At the moment I don't plan to add a scrubber but I will keep watching in case I decide to add one later.

 

[Justfbilly]

Cat litter lol. I would have never guess. Was it a specific type? How would you know when its exhausted? I suppose the pH level will indicate it.

I am getting ready to run a closed loop outside for a small chiller and while I am at it I may run a fresh air line as well. At the moment I don't plan to add a scrubber but I will keep watching in case I decide to add one later.

It was fresh step with carbon. I thought the same thing when I saw the video but the results looked promising. I am not sure if it will work under a large load like a reef tank but it's certainly worth a try

 

[Lasse]

I have also have some ideas about using limewater instead of the crystals. The problem is that you probably have to use an airpump.

I have also been thinking of regenerate the media. To work as Crystals - the media needs some water - it needs to have some humidity. During use - it will dry out and stop to working - but most of it is still calcium hydoxide.

I have one idea that i will test - its include potato

Sincerely Lasse

 

[Urville]

This is based on an experiment I saw done in either high school or college. I think it was college.
Relevant links:
The Degradation of Limewater in Air by Randy Holmes-Farley
https://goo.gl/nqmYMo

Limewater and Carbon Dioxide - Flinn Scientific
https://goo.gl/E48L3Y

Dry Ice and Limewater (Heat to recharge?)
https://goo.gl/zGHpZ6

 

[CoralWealth]

any update on this stuff?