The ocean carbon cycle can lend some ways to render carbon dioxide into other forms that will not be used to associate with climate change.
Carbon dioxide and calcium compounds have always been in an enduring relationship responsible for buffering the pH of the sea thus maintaining the marine life. Nature itself made this chemistry. We may borrow this concept; it has no patent: it’s free.
When I was a freshman, we were asked in our biology class to submit a term paper for the conversion of food-based kitchen waste into something useful. Mine was turning sweet potato peelings into ethanol. I got the idea in the walkway of our campus leading to the thoroughfare area, where there were small food carts selling a good budget afternoon snack, fried sweet potatoes. Whenever I passed the walkway, I noticed the pile of the peelings dumped by the wall. I thought about converting it into something else and my professor gladly accepted it for my topic. It was in 1995.
For help, I approached a graduating schoolmate, a senior, and asked if the sweet potato peelings could be converted into something flammable because of the noticeable volatile smell similar to our lab’s during organic chemistry class. I was advised to quit the fancy because it was just a term paper, not a thesis. He went on to burst my bubble telling me as freshman in the first semester at that, I wasn’t ready for organic synthesis. He then asked me to ask to meet his biochem professor in the faculty who subsequently gave me a crash course on saccharification and fermentation while complaining about my being a slow learner.
While this was my baptism of fire to saccharification and fermentation, this write-up is not about ethanol; this is about the possible way of saving carbon dioxide for its industrial value.
After my class, I rushed up to the lab to check out my setup. I saw my bottle of saturated CaCl2(aq) solution still bubbling through and a 6 mm, 2 feet transparent hose attached to the lid of my fermentation bottle. In this setup, I need to bubble the CO2(g) from my fermentation bottle into a bottle filled with saturated CaCl2(aq) solution. The CO2(g) was bubbling off more robustly that it was the day before. The natural ambient temperature in my tropical country kept the fermentation condition at an optimum.
When I came back from a boring class, I saw white flakes at the bottom of CaCl2 bottle. It was a sight to behold during my naïve days. I find it amazing that some gas bubbled into some clear salt solution could produce white flaky precipitates. My sleepless nights paid off. The boiling of sweet potato peelings in dilute sulfuric acid until the refractometer readings of the aliquot is constant. The neutralization and pH adjustment of the filtrate and finally the days of fermentation while observing the formation of the CaCO3(S) at the bottom of the CaCl2(aq) bottle was very rewarding. The utter simplicity of it all surprised me. We can emulate the carbon cycle from the ocean with a little modification. I remember my freshman project while thinking about calcium and its forms.
It is no hallmark that calcium could lock the CO2(g) in solid form. Currently, we are reminded over and over that anthropogenic CO2(g) is at critical levels. We can only strive to feel better.
Air can be bubbled into a solution of CaCl2(aq) in the hope of scrubbing out the CO2(g) and convert them to CaCO3(S). Maybe, with the amount of CO2(g) we’re told to be already in the atmosphere, we could produce enough CaCO3(S) that there was no need to mine limestone at all. Well, mining is an environmentally disastrous activity no matter how we sugarcoat it, and no euphemism can change the fact that mining could mean balling of trees, chemical tailings and of course, more carbon dioxide, SOx and NOx from heavy equipment.
Calcium carbonate has a lot more to offer than being an ingredient for cement. Upon heating, it gives off CO2(g) that can be compressed in cylinders which can be turned into dry ice. It can be fed into vertical farms for artificial photosynthesis that grows food in a fertilizer and pesticide free environment with small land footprint which helps avoid deforestation.
In the event that the surface air may not enough produce CO2(g) for the production of CaCO3(S) to an industrial level, this is perhaps despite their density, CO2(g) reside in upper layers of the atmosphere. If so, it is inconvenient to tap into that abundance.
Alternately, the farm has a potential to produce CO2(g) in an amount that could sustain a small and decentralized system. The cellulosic farm residue can be enzymatically converted to ethanol. Ethanol burns to produce 2 moles of CO2(g) per mole ethanol. If ethanol is fed into a spark-ignited engine of a power generator, the exhaust can be bubbled into a solution of CaCl2(aq) to produce CaCO3(S) while producing the electricity needed in the farm. The CaCO3(S) can be reacted with HCl to produce CO2(g) and CaCl2(aq). This CaCl2(aq) can be split into elemental calcium and chlorine gas by a well-established electrochemical technic. It goes without saying that the Cl2(g) is also an important reagent with an industrial role. It should be collected and compressed into tanks for future use. The elemental calcium can dissolve in water. Not as animated and fiery as some of its Alkali metal cousins like sodium, potassium and lithium, but can dissolve nonetheless to form Ca(OH)2(s) and hydrogen molecules, H2(g) can also be compressed into tanks for future use.
Of all the clean technology innovations, H2(g) seems to be the best with the number of practical applications and all emit only one GHG which is the water vapor. The H2(g) can be fed into an internal combustion engines and fuel cells, but I can only enumerate two. Carbon dioxide is more compressible than air. Perhaps it is possible to blow it into gas turbines to produce electricity. But this is too optimistic for simple farm living.
While the modified carbon absorption style is simplistic due to its concept which is too elementary, it might work. If you’re onto a decentralized and minimalist lifestyle tucked away from Tinseltown, this might be a life for you. Imagine sitting in the middle of some farm watching “Chicken Little” made possible by a CO2-less electricity from ethanol synthesized from farm residue.
This is opinionated. This was not academically reviewed. Kindly do your own research before believing anything I wrote here. Thanks.
By: AJ Martirez
Edited and Proofread by: Kristine Paraiso
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