Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Scientists break down plastic using a simple, inexpensive catalyst and air

phys.org

Post reply on HN
Print view View original

21–30 of 113 posts

Re: Scientists break down plastic using a simple, inexpensive catalyst and air

#21

Post by PaulHoule »

culi wrote: post #20
PaulHoule wrote: post #7

Earlier quoted context omitted.

This is contrast to the pyrolysis-based "chemical recycling of plastics" which makes a mix of petrochemicals similar to what you find in the BTX stage of a petrochemical factories [1], especially for condensation polymers like PET. That is, this process produces fairly pure Terephthalic acid [2] and Acetaldehyde [3] and the first of those could be recycled into more PET. The thing is BTX chemicals and other precursor…

> about 50 cents a pound which makes it hard for any kind of recycling process to be competitive. We've had almost a century of subsidization of the oil industry. The gov't needs to play a bigger similar role if the recycling industry is ever gonna be able to compete We need a tax on the full lifecycle cost of plastics so we can stop treating waste as an economic externality

Landfilling plastics on the other costs about 4 cents a pound. The nightmare scenario about plastics is not that they get landfilled but that people chuck them on the ground and they find their way to the ocean and get ground up into microplastics.

Re: Scientists break down plastic using a simple, inexpensive catalyst and air

#22

Post by hinkley »

kibibu wrote: post #5
kikokikokiko wrote: post #2

Well, they used a "simple, inexpensive catalyst" and then HEATED the plastic/catalyst mysture. Nowhere in the article it gives you an estimate of the final cost of the process.

The journal article is open access. https://pubs.rsc.org/en/content/articlelanding/2025/gc/d4gc0... > Catalytic amounts of AC/MoO2 selectively convert waste PET into its monomer, terephthalic acid (TPA), within 4 h at 265 °C with yields as high as 94% under 1 atm air. I'm not a chemist so don't know if you can find a way to calculate the cost, but the authors claim that it's cheaper than current methods. The bigger d…

4 hours sounds like a lot of factory space to generate a substantial flow of output.

Re: Scientists break down plastic using a simple, inexpensive catalyst and air

#23

Post by hinkley »

roughly wrote: post #16
jandrese wrote: post #8

Earlier quoted context omitted.

That's within the range of a kitchen oven. The biggest problem is that plastic is so cheap that even that relatively modest energy use may make it uneconomic compared to virgin TPA, especially if you have to clean the inputs thoroughly first.

In fairness, that’s mostly because current plastic production externalizes the cost of everything about the lifecycle before and after manufacturing and use.

Tariff on virgin, and at least half the same for recycled material.

Re: Scientists break down plastic using a simple, inexpensive catalyst and air

#24

Post by iwontberude »

culi wrote: post #18

This is great but PET (symbol #1) is one of the few plastics that ARE recyclable. I wonder if any of these techniques can be used to solve the non-recyclable plastic problems

Not infinitely so, maybe this is used on old PET

Re: Scientists break down plastic using a simple, inexpensive catalyst and air

#25

Post by ta988 »

hinkley wrote: post #22
kibibu wrote: post #5

Earlier quoted context omitted.

The journal article is open access. https://pubs.rsc.org/en/content/articlelanding/2025/gc/d4gc0... > Catalytic amounts of AC/MoO2 selectively convert waste PET into its monomer, terephthalic acid (TPA), within 4 h at 265 °C with yields as high as 94% under 1 atm air. I'm not a chemist so don't know if you can find a way to calculate the cost, but the authors claim that it's cheaper than current methods. The bigger d…

4 hours sounds like a lot of factory space to generate a substantial flow of output.

Those processes can be made continuous most of the time.

Re: Scientists break down plastic using a simple, inexpensive catalyst and air

#26

Post by Gigachad »

PaulHoule wrote: post #21
culi wrote: post #20

Earlier quoted context omitted.

> about 50 cents a pound which makes it hard for any kind of recycling process to be competitive. We've had almost a century of subsidization of the oil industry. The gov't needs to play a bigger similar role if the recycling industry is ever gonna be able to compete We need a tax on the full lifecycle cost of plastics so we can stop treating waste as an economic externality

Landfilling plastics on the other costs about 4 cents a pound. The nightmare scenario about plastics is not that they get landfilled but that people chuck them on the ground and they find their way to the ocean and get ground up into microplastics.

Or that they just shed microplastics during their lifetime. Car tires and clothing being a huge source.

It would be cheaper to just ban stuff like polyester fleece than to try to clean it up after.

Re: Scientists break down plastic using a simple, inexpensive catalyst and air

#27

Post by hinkley »

ta988 wrote: post #25
hinkley wrote: post #22

Earlier quoted context omitted.

4 hours sounds like a lot of factory space to generate a substantial flow of output.

Those processes can be made continuous most of the time.

You've still got Little's Law though. You either need a very giant machine or a very low feed rate in order to have stuff come out one end 4 hours after going in the other. I think steel recycling may be faster than that.

Re: Scientists break down plastic using a simple, inexpensive catalyst and air

#28

Post by m463 »

kikokikokiko wrote: post #2

Well, they used a "simple, inexpensive catalyst" and then HEATED the plastic/catalyst mysture. Nowhere in the article it gives you an estimate of the final cost of the process.

I wonder if processes like this can recycle the heat?

Kind of like fresh air exchange into a heated house where new air in gets heated exchanging with old air out

Re: Scientists break down plastic using a simple, inexpensive catalyst and air

#29

Post by timschmidt »

Gigachad wrote: post #26
PaulHoule wrote: post #21

Earlier quoted context omitted.

Landfilling plastics on the other costs about 4 cents a pound. The nightmare scenario about plastics is not that they get landfilled but that people chuck them on the ground and they find their way to the ocean and get ground up into microplastics.

Or that they just shed microplastics during their lifetime. Car tires and clothing being a huge source. It would be cheaper to just ban stuff like polyester fleece than to try to clean it up after.

Or we could price cleanup and recycling of the constituent materials into the purchase price by requiring manufacturers to pay to recycle all the items they manufacture.

This approach closes the loop in a way which encourages manufacturers to re-engineer their products to be less expensive to recycle.

Re: Scientists break down plastic using a simple, inexpensive catalyst and air

#30

Post by ac29 »

culi wrote: post #17

What percentage is actually broken down into monomers? How much microplastic waste is left behind. Given the reliance on "ambient air" I imagine it's not 100%. Regardless, I'm excited to hear about progress on solving the plastic waste crisis. It seems better than the current alternatives the article presents: > "The U.S. is the number one plastic polluter per capita, and we only recycle 5% of those plastics," said N…

> What percentage is actually broken down into monomers?

"In just four hours, 94% of the possible TPA was recovered."

Post reply on HN