Yes. I can break down plastics that way, using ordinary tap water.

Actually, the tap water is optional.

And instead of monomers, the end product is carbon - which is even more recyclable!

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 deal imo is that it recovers PET monomers from mixed plastics, which means avoiding manufacturing more plastic.

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 precursors of mass produced plastics cost about 50 cents a pound which makes it hard for any kind of recycling process to be competitive.

[1] https://en.wikipedia.org/wiki/BTX_(chemistry)

[2] https://en.wikipedia.org/wiki/Terephthalic_acid

[3] https://en.wikipedia.org/wiki/Acetaldehyde

> 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.

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.

Cleanup is impossible though. How are you going to clean up a trillion nanoplastic dust particles? What is the effective difference between phasing out fleece clothing vs charging $100M for a jacket?

One includes freedom and creates an economic incentive for the development of environmental rehabilitation, recycling, and carbon negative technologies.

If some celebrity wants to single-handedly fund the development of a microplastics recovery technology as part of a red carpet fashion item, I'm OK with that.

The problem with this is it doesn't give any consideration to the feasibility of alternatives or timelines to change things. If you just drop a blanket "every product must include it's cleanup costs", you're telling the public that their current life essentials are now unbelievably expensive.

Vs selectively picking products which have easy alternatives and providing phase out periods which match the difficulty of replacing them. If you tell the public you are going to make car tires cost millions of dollars, you'll be voted out. If you tell them that plastic confetti will be replaced with paper confetti in 12 months you'll make real progress.

This doesn't prevent innovation. Scientists will still do research, develop new recycling tech and processes.

The trouble is that the market allocation of funding is dependent on the valuation of goods and services. Until the externalized costs are accurately represented, the market will under-allocate capital toward solving the problem. To push the transition to happen faster without internalizing costs, you'd have to subsidize development with significantly more cash than the market would be willing to allocate with accurately internalized costs. Which I'm not sure is possible.

There are definitely reasons to subsidize some products - medical devices, for instance - as you say, things without readily available alternatives. I'm not writing a detailed transition plan here, just pointing out observations.

If $100M is what it would cost to internalize the economic externalities of fleece then that is the true fair price of the item. Anything less than that is a subsidy

We are subsidizing these materials with our health and our environment. And it affects certain people more than others—usually people who have the least say in it

A 100% linen shirt currently costs around $40 and, when cared for properly, can last a lifetime. Rubber bands made out of natural rubber are much stronger and will last at least 10x as long as plastic ones and are about the same price. I could go on, but the alternatives exist and are already often much cheaper in the long run.

But a $100M price tag is exactly equivalent to a blanket ban, so you're not fundamentally disagreeing with the person you're responding.

You're just over rationalizing it with 101-level economics ;).

$100M is certainly an overestimation and some types of pollution are more solvable than others. In general I think it's important for price tags to communicate the full price of an item

Also no need for the patronizing comment. Economic externalities are a valid criticism of market failures and you haven't provided the more convincing, "advanced economics" jargon-laden analysis you're pretending to harbor

The original comment was talking about cleanup costs. You realistically can not clean up shed microplastics. A fleece jacket sheds millions of them every wash as well as just wearing it. How are you meant to collect all of those microplastics that just blew off in to the air.

So just a blanket "Charge everything based on it's cleanup costs" doesn't work.

Same way you do asbestos remediation. Enclose the area, filter the air, create a clean room around the entire area.

Maybe in the future you laser-atomize every spec that floats past the actor inside an 8ft cube. Who knows?

I don't think it'd be practical to switch overnight - much of our societal infrastructure needs re-engineering for sustainability which will take time - perhaps a gradually increasing percentage of externalized costs can be integrated over time. It'd be real progress toward a Venus Project style resource based economy.

> $100M is certainly an overestimation and some types of pollution are more solvable than others. In general I think it's important for price tags to communicate the full price of an item

In theory, I agree with you, but trying to internalize these cost is itself extremely costly. That's why the criticism about econ-101 level reasoning: it's a convincing idea in theory that isn't tractable at all in practice and can only end up with a bureaucratic nightmare.

The EU has many such rules that are designed around economics first principle like that, in order to build an “efficient market”, and they are all extremely burdensome and at the same time ineffective (see EU-ETS, the single Electricity market, CBAM, etc.)

In the realm of policies, tractability is always preferable to theoretical elegance.

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.

Yeah, these are pizza oven temperatures. The temperature appears to be just above the melting point for PET. It is also in the liquid phase for PBT, PEN and PEF.

I think most recycling methods for PET require melting anyway.

Also manufacturing, so importantly this might be more energy efficient and maybe even cheaper than making new plastic. Depending on how the monomer->PET part gets solved.

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.

The authors' claim is that it is cheaper than other catalytic methods that have been explored/invented to depolymerize PET into TPA monomers. These qualitative cost estimates are based on the reaction conditions (temperature, solvent, other reactants (in this case, humid air)) and the unit operations involved in the downstream separation processes that isolate the TPA product from unreacted PET. The largest hurdle that precludes widespread deployment of technologies for PET recycling, as well as those for most other plastics, occurs (way) upstream of the reaction and separation train. The highest cost is related to collecting and sorting used PET bottles and TPA-derived textiles.

Mechanical recycling or any flavor of chemical recycling (pyrolysis, hydrolysis, etc.) all suffer from the same hurdle. If the target product of the recycling process is a TPA-derived plastic (be it for clothing or soda bottles), then mechanical recycling is usually cheaper, since it produces a product that only needs to be reshaped and remolded to give shirts or jugs. Chemical recycling converts PET into its constitutive monomers, and to (re)produce a TPA-derived plastic from the monomers requires a not inexpensive (re)polymerization step, in addition to reshaping and remolding.

Chemists, even highly regarded ones like Tobin Marks, are less interested in "solving" the PET recycling issue and more interested in the fundamental chemistry involved in chemical recycling. Issues of Green Chemistry (or blurbs in phys.org) are not the appropriate reading materials to get insight into costs, scale-up, etc.. Very few, if any, academic journals are focused on such matters, and rightly so, in my opinion.

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

Short answer: yes.

All industrial processes recycle heat extensively. Heck even distillation based desalination isn't that inefficient because you do in fact recover the heat.

Keep seeing these "possible breakthroughs" in breaking down plastic waste, but no concrete time frames on expanding to scale nor real world costs. Meanwhile, the mountains of plastic continues.

Finding it also odd that biodegradable plastics and safer alternatives are going quiet. As if the new scheme is to keep fossil fuel companies rolling, with the promise that one day a solution to get rid of incalculable mountains of plastic will be found. Don't worry, feel free to plastic pollute, because one day there will be a solution.

Incalculable mountains aren't a real environmental problem. People just believe that for some reason. We can just leave them there forever. The actual environmental value in recycling is reducing the CO2 emissions from making new plastic by reducing production of new plastic. I don't know if biodegradable plastic actually helps at all or just placates the people worried about the fake problem of incalculable mountains.

I'm not sure why you have the take that plastic pollution is not a problem. If anything, it is a massive catastrophe that threatens the environment and possibly the human race. Plastic pollution is destroying the environment[1], wildlife[2], and damaging humans[3][4]. That includes newborn babies[5].

[1] https://www.unep.org/plastic-pollution

[2] https://www.biologicaldiversity.org/campaigns/ocean_plastics...

[3] https://www.nationalgeographic.com/science/article/microplas...

[4] https://www.nationalgeographic.com/premium/article/microplas...

[5] https://scitechdaily.com/startling-discovery-scientists-find...

I'm talking about plastic waste in landfills ("mountains").

Biodegradable plastics suffer from either being hard to degraded or hard to use without degrading. It's a difficult conundrum

> Finding it also odd that biodegradable plastics and safer alternatives are going quiet.

They tend not to be a good solution to anything.

There are a couple of ways of making degradable plastic. One is to add something to their manufacture so they break down into shorter chains which their supporters tell you will then further break down. These are generally referred to as OXO degradable.

Another is to use bio based plastics such as PLA or cellulose. These both have poor performance compares to oil based plastics.

All of these also require industrial composting where they add no nutrition to the compost, effectively just bulking it out. They [generally] do not break down when littered or even placed in a domestic compost heap.

There is also a problem because these plastics are virtually impossible to sort from recyclable plastics so if they get in each other waste stream the whole batch can be rendered contaminated and useless.