Note that the chloralkali process requires electricity, which, at least right now, comes mostly from fossil fuels. I guarantee this process is not as carbon-negative as the company claims.
The problem is that’s not sequestering the carbon. It will be exhaled or released at the wastewater treatment plant that is the destination of human-edibled creatures.
NO NO NO! We don’t want something like that contaminating the natural habitat!
Solfy: The only way to have more trees is to have fewer people. The only way to have fewer people is to have more wars. (Yes, that includes wars to introduce the concept of family planning.) Wars are never carbon-neutral. Humans are eternally fucked.
I think one or the other of us just got whooshed. When Malacandra mentioned having an organism sequester carbon in calcium carbonate the first thing I thought of were clams. AIUI the shells are mostly CaCO[sub]3[/sub], so they were the first critter I thought of. And, normally, most people don’t eat the shells with the meat.
AIUI, CaCO[sub]3[/sub] from shells makes one of the sources of supplemental calcium sold in stores, so some of it does get digested - but it’s not the normal mode when people have clams.
Mala whooshed a bunch of folks, I think. There’s a ton of different creatures that use CO2 to make shells. The White Cliffs of Dover are a perfect example of ancient shells becoming stone and thus sequestering the CO2.
Swimming pools for everybody!
*points and laughs at a bunch of folks, but mostly *Quercus 
It’s that whole Cretaceous Period thing.
The thought that comes up for me is the difference between finding new uses for already created “waste” products, which is what I understand the eggshells in the linked article to be, and expressly farming a critter to sequester carbon. I’m also not sure that the process mentioned is suitable for sequestering, rather than simply controlling emissions, which I understand to have two differening (though obviously related) sets of criteria.
My gut feeling (and it’s one I’ll admit that I can’t substantiate at this time) is that for carbon sequestering the goal would be to maximize the amount of carbon bonded into CaCO[sub]3[/sub] matrixes, while minimizing the metabolic carbon that those same critters would be releasing. With the exception of the cuttlefishes my impression is that most critters that make shells for themselves (instead of putting a shell around thier eggs) can be considered as having that same shell describing their external boundaries. It would seem to me that to take advantage of cube-square relationships, you’d get the most bang for your metabolic carbon by farming small critters that would be putting a lot more of their energy budget (percentage-wise) into creating that shell. So, I would think that the ideal critter would really be a coral, or one of the carbonate shelled plankton.
The next question would then become: How durable is the shell? Which is where I suspect microfauna would lose out. One of the reasons that clam shells seemed so good to me was that they’re relatively hard to digest, requiring more in the way of mechanical processing to make the components avaiable for use by other organisms. There are probably ways around these issues, of course. I imagine making bales of microfauna shells and dumping them over the abyssal plains would do pretty well for sequestering that carbon.
Of course, such mechanical processes would increase the carbon release for this sequestering plan… :smack:
Hey, watch that. That is only a small part of our small state.
This is a prime example of the idiots out there touting CO2 absorbing schemes. From the cite
“That brought them to eggshells, which mostly consist of calcium carbonate – one of nature’s most absorbent materials. It is a common ingredient in calcium supplements and antacids. With heat processing, calcium carbonate becomes calcium oxide, which will then absorb any acidic gas, such as carbon dioxide.”
Wait a minute - use expensive heat to turn CaC03 into CaO and CO2, and use that CaO to capture a different batch of CO2 - what are you going to do with the first CO2 you produced?. And where are you going to get millions (billions?) of tons of eggs shells needed? This guy should be sacked form his department for being a wasted space. [/spleen vented]
The researchers in the article are not trying to sequester carbon. They are trying to remove CO2 from a Hydrogen-CO2 mix, leaving just the H2. (But you’re right that this won’t result in a net reduction of CO2.)
whoops, mea culpa. I still think they are way off beam, for instance
“About 10 percent of the membrane consists of collagen, which sells for about $ 1000/gram. This collagen, once extracted, can be used in food or pharmaceuticals, or for medical treatments. Doctors use collagen to help burn victims regenerate skin; it’s also used in cosmetic surgery.”
Collagen is the most abundant protein around and one of the cheapest - bulk prices probably less than 5$/kg. The stuff they use in surgery is from specially bred cows, and I suspect some post modification to make it hypoallergenic.
It would probably still be cheaper to use NaOH as the absorbant than heated chicken eggs.