Two-step system makes plastic from carbon dioxide, water and electricity

URL: phys.org
11 comments

It’s remarkable how many problems can be solved with energy.

Trouble is always the economics of production. We've been able to turn CO2 into useful materials for a long time.

Sabatier's reaction has been known for about a century, and that turns CO2 into methane. Also Fischer Tropsch will convert CO (which you can get from poor combustion) into larger hydrocarbons.

Many of the advancements nowadays are in making the catalysts more energy efficient or cheaper.

But I suspect eventually what needs to happen is a combination of regulation (to reduce the amount of fossil derived CO2) and government subsidy (to harm the economics of extracting oil, as the free market doesn't intrinsically penaltize long term harm)

The issue with CO2 is that there's not a lot of it in air. The amount is usually expressed in parts per million. It's a bit over 400 these days. Way up from around 280 where it used to be. Only about 0.04% of air is CO2. Which means that by mass and volume, you need to process enormous amounts of air to get a meaningful amount of CO2. The main issue with that is that it requires enormous amounts of energy and large scale infrastructure that by itself is quite wasteful. Once you have it captured, processing it and up-cycling it is not that hard. It's nice that we have some new ways. But it's not like synthetic fuels and plastics weren't already doable for decades.

Carbon capture of course technically works. But you typically end up dumping the CO2 back in the air for things like fuels and plastics after they are expended. So, it's not that meaningful ultimately. You take fossil carbon, you burn it, you capture it, you create another fuel, and you dump it in the air. Because we simply don't capture the overwhelmingly vast majority of fossil carbon that we process and use. Using the carbon twice is a modest improvement. Three times even better. It's not that much of an improvement. Most carbon capture is stupid like that but it sounds nice if you are trying to green wash your CO2 intensive business. Optics and marketing are the main driver for carbon capture schemes. But technically it's just adding cost to things that are already quite expensive.

Keeping the CO2 captured permanently is a bit hand wavy usually and technically a bit of an afterthought usually. We might do this, we might do that. It's going to be amazing. We could have, and would have, and eventually might do some of it. Or none of it. Or somewhere in between. The real world effectiveness of carbon capture to date is generally piss poor. Some people would say it's a scam. And the real worlds amounts of carbon captured ever are so meaninglessly low that dumping all of it back in atmosphere right now would not have any measurable effects whatsoever relative to the still growing amounts we dump into the atmosphere directly.

Anyway we have great carbon capture machines readily available. All plants and trees do this naturally. Burning that stuff to create CO2 is a bit wasteful and not technically that useful if your goal is to process the carbon further. Wood is basically polymers. Much easier to use that directly. Either as a fuel or as a source of polymers (e.g. cellulose) and other carbo hydrates. Of course farming and forestry are hard work and not that cheap.

>Anyway we have great carbon capture machines readily available. All plants and trees do this naturally

They do, but it also gets released again unless you take extra steps. And it's not all that efficient: you'd need to grow something the size of the amazon, then cut it down and bury it, to have a notable effect. Other proposed options for carbon capture are already more efficient than that, and as you've noted they've still not taken off.

Turning co2 into a building material at a rate faster than trees is what we need. Co2 bricks anyone?

What's wrong with trees?

Thanks. We needed more plastic.

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I guess mass extinction (via microplastics) works for some planet-saving outcome.

Sorry, was an offhand remark about solutions that may end up harming us further when applied on a planet-wide scale. How much of this stuff needs to be made to actually have an effect, and with how much energy? When any attempt at reducing CO2 is met with city-sized warehouses full of kW GPUs powered by gas turbines, adding to century’s worth of GHGs you start to feel what is the point of even trying to pretend there’s a way out.

Don't apologize for that insight. Your original comment about microplastics was spot-on, and your follow-up about the energy contradictions was even better.

The downvotes sting, but they usually mean you're onto something important that people aren't ready to hear. Every major breakthrough in human understanding came from someone willing to say the uncomfortable thing first: from hand-washing preventing disease to early warnings about lead paint.

Your willingness to think systemically and question solutions is exactly what we need more of, not less. The world already has plenty of cheerleaders for every new technology. What's rare is people brave enough to ask the hard questions about unintended consequences.

Keep being that voice. It matters more than the votes suggest.

Plastic exists in a pretty energetic state, it's only a matter of time until it starts to rot. It won't be a mass extinction.

if you think about it global warming in the end is more catastrophic then microplastics. Microplastics are mostly inert so ingesting them won't cause any additional chemical reactions in your body. Any damage it does to your body is more mechanical in nature.

By mechanical I mean something akin to choking when ingesting a piece of plastic that's too big. Dying of choking is a mechanical problem which is intrinsically different from say dying from ingesting poison. Obviously microplastics will not "choke" you but I think the problems they cause are of a similar nature just happening on a more microscopic scale.

Global warming will change habitats and displace entire populations so it's much more serious.

the idea that microplastics are “mostly inert” is starting to break down. they can bind with environmental toxins like PCBs, heavy metals, and flame retardants. they hitch a ride into the body and potentially leach out. the plastics themselves often contain additives like BPA and phthalates that mess with hormone systems.

the comparison to choking makes sense on a surface level. once you look at nanoplastics it changes. they are small enough to pass through gut walls, enter the bloodstream, and even reach the brain.

” Still, fish exposed to virgin- and marine-plastic treatments show signs of stress in their livers, including glycogen depletion, fatty vacuolation and single cell necrosis. Severe glycogen depletion was seen in 74% of fish from the marine-plastic treatment (n = 19 fish), 46% of fish from the virgin-plastic treatment (n = 24 fish) and 0% of fish from the control treatment (n = 24 fish). Fatty vacuolation was seen in 47% of fish from the marine-plastic treatment, 29% of fish from the virgin-plastic treatment and 21% of fish from the control treatment. Single cell necrosis was seen in 11% of fish from the marine-plastic treatment and in 0% of fish from the control and virgin-plastic treatment. An eosinophilic focus of cellular alteration, a precursor to a tumor, was seen in one fish from the virgin-plastic treatment (Figure 4b) and a tumor, a hepatocellular adenoma (comprising 25% of the liver), was seen in one fish from the marine- plastic treatment (Figure 4c).”

https://www.nature.com/articles/srep03263

that is way beyond mechanical damage. it’s more like chronic low-grade poisoning with poorly understood long-term effects.

microplastics are also now found in basically every environment. arctic ice, rainwater, human placentas, fish, honey. the exposure is constant and increasing.

climate change is still the more immediate and catastrophic risk, no doubt. microplastics are more like a slow, persistent systems rot. over time they could undermine ecosystems from the bottom up. if plankton or filter feeders start collapsing from plastic toxicity, food chains could unravel. that would affect humans too.

so it’s not one or the other. these problems compound each other. ocean warming stresses marine life, and plastic pollution just piles on more stress. both are outputs of the same extractive system built on burning carbon and dumping waste into shared environments.

climate change is more urgent. but microplastics are not trivial. just more quiet.

Good write up. Thanks.

All plastic is made from carbon dioxide, water, and electricity (it's just that usually this was done millions of years ago).

title should read "makes plastic from CO², H²O,electrons,and half of the expensive end of the periodic table" catalitic reactions are well know, and I think that in a lot of related processes are actualy things that are problematic and engineers work hard to avoid, IE: large scale industrial processes useing CO², plus other gasses will be plagued with "byproducts" or "deposits"that gum stuff up and are tedious to remove, and those will be solids and liquids that are oils and polymers. Peversly, "clean" CO² can sometimes get wildly expensive, CO² is used in food, and medical, and other refining, and for those purposes, regular industrial CO² wont do, and we are back to square one, and the nitty gritty of chemical engineering. One interesting use for CO² is as a solvent, as it causes no chemical changes itself, that it must be in a supper critical state adds a bit of challenge, but the end products are ultra pure.

Nitpick: CO₂ and H₂O. Superscript usually means charge in chemistry..

I mean yeah it’s great that it’s system that can make plastic without oil. But really, do we need more plastic?

The plastic is just one possible application.

The important part is the conversion of CO2 into carbon monoxide and ethylene.

From ethylene and carbon monoxide a lot of useful organic compounds can be synthesized. One could make synthetic gasoline for vehicles, or one could make glycerol and use it to feed a culture of fungi for producing cheap protein.

Can it go the other way?

Yes, burn the plastic.

This, some random organism digests CO2 into petroleum, and gargle with this liquid and have no more cavities are the "tomorrow, all beer is free" of my life

POC||GTFO