logoalt Hacker News

condimenttoday at 3:08 PM10 repliesview on HN

At current rates of emissions, we’re only about 20 years away from people needing to install CO2 scrubbers in their homes.

Soda lime, or calcium hydroxide, is the current state of the art. We use that in an anesthesia and in saltwater aquariums and in scuba rebreathers. An idealized system can capture 500 mg per gram, but in practice you only capture around 250mg/g. This outperforms the method in the article but it’s one-shot. There are interesting proposals to use this for direct capture at industrial facilities and to turn the waste material into bricks for building.

The key advantage of this new material appears to be that it can be heated and reused. That would be very valuable in an interior direct air capture use case. Think about filtering the CO2 from an office or a home to get us back to pre-industrial levels indoors.


Replies

UniverseHackertoday at 3:34 PM

I think it’s little appreciated that high CO2 levels cause cognitive impairment, and with the same amount of (often very poor) air exchange, higher outdoor concentrations can push indoor spaces to levels that cause impaired cognition and poor sleep. I’ve already been seeing this in my home, and will often open windows even when cold just to keep co2 levels reasonable. One solution that can help is an external air heat exchanger, which can exchange air with the outdoors without compromising your homes heating and cooling like an open window will do.

Noticeable cognitive impairment starts in the 700-1000ppm range, whereas it is very common for homes to reach 2000-3000ppm, especially when in a closed bedroom.

show 10 replies
marcosdumaytoday at 3:35 PM

> The ease of releasing CO2 is the key advantage of the new compound.

I have no idea why the journalist that wrote this article choose to highlight the carbon density of the sub-header. It's almost completely irrelevant for carbon capture plants.

Another clear benefit is that it's a liquid.

Today people mostly use the substances that you called non-reversible in research plants (AFAIK, all plants are research right now). They are perfectly reversible, but that uses a lot of energy.

show 1 reply
netcrafttoday at 3:15 PM

160F, non toxic, this already sounds like something that could feasibly be used in the home. I would already be interested in installing one. And would absolutely love to see what it would do to school performance.

The hard part is capture and disposal.

bilsbietoday at 5:37 PM

Just to counter your extreme prediction, if co2 levels halve from here all life on earth goes extinct.

https://www.researchgate.net/post/Minimum_necessary_concentr...

show 1 reply
yodontoday at 3:13 PM

Do you have a citation for that 20 years estimate?

show 4 replies
jiehongtoday at 3:34 PM

Could something like this be used to make cement?

Imagine capturing CO2 to turn it into cement, used for constructions.

Pardon my ignorance, though.

show 2 replies
DivingForGoldtoday at 5:36 PM

"outperform" by only one metric too often fails usefulness. It's a one shot unless you heat the calcium carbonate to 900C, the compound in the article only requires 70C, and has quite a bit of ability to re-process CO2 absorption multiple times. Although solar ovens could reach over 900C, probably too dangerous for residential use.

adrianNtoday at 3:17 PM

You can heat definitely heat NaHCO3 to get CO2 and NaOH back. It just takes a lot of energy.

omgJustTesttoday at 3:38 PM

citation for the co2 scrubbers in home need?

show 1 reply
29athrowawaytoday at 3:28 PM

Maybe we just need to make cyanobacteria that multiplies faster.