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

phys.org

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

#71

Post by XorNot »

lxmorj wrote: post #37

Wouldn't (fully) burning all single-use plastics effectively make them no more long-lived and problematic than burning crude oil at sea? I know that's a low bar, but it seems like at least you're getting two uses out of them at that point...

Landfilling plastics avoids even putting CO2 back into the environment.

Modern landfill is highly engineered and extremely stable: what goes in there stays there.

Plastic starts as oil in the ground. Replacing it as solids in the ground isn't a problem.

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

#72

Post by XorNot »

m463 wrote: post #28
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

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.

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

#73

Post by PaulHoule »

piokoch wrote: post #50

There is no such a thing like "plastic". The article is about PET - polyethylene terephthalate, there are hundreds other "plastics", which different chemical propensities. The problem is not actual act of recycling, but figuring out what a given piece is made of. PET is popular - 70% of all bottles are made of it, but there are those 30%, so the most expensive part - sorting - has to be carried anyway. Plus we target…

The first few numbered plastics have different physical properties and can be sorted roughly by physical processes such as floating them on water. Past that you need more sophisticated techniques, maybe robots.

Those clear PET bottles for instance are common and worth recycling, but if a brand makes green PET bottles those need to be separated from the clear ones if you want good-quality clear PET which can be used to make clear PET bottles or blending with a colorant to make green bottles.

Many of the big brands are standardizing on clear PET, both Coke and Pepsi are even using 100% post-consumer bottles in some geographies. In gas stations in upstate NY I frequently see Coke products bottled in 100% post-consumer recycled clear PET bottles.

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

#74

Post by harrall »

nervousvarun wrote: post #56
mc32 wrote: post #54

Earlier quoted context omitted.

Only in some ways. Mostly it’s due to use case and desired characteristics of the container, one of which can be cost. As another poster noted, different products need different packaging solutions.

That's an important point you're making here...Can you expand on that with an example? A specific use of plastic as a container that gives the desired characteristics...specifically where those characteristics could not be met by another (if expense isn't a consideration) material? If there are less toxic materials that could "do the job" but are more expensive then it really is about money no?

If you look at it holistically, I might get boxed cereal from the grocery store that’s bagged in a cheap, microbe-blocking, shelf-stable and lightweight plastic bag in a cardboard box.

I could also go to a bulk goods store instead and fill a container.

But one of these options is much more convenient… and that’s fundamentally why society is having hell of a time getting rid of plastic. These plastics are bad for the environment but they bring a lot of material properties that other materials like metal, wood or glass don’t provide.

Obviously bagged cereal is a drop in the bucket but this materials calculus is applied everywhere and at every stage.

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

#75

Post by neilknowsbest »

Mashimo wrote: post #49
lxmorj wrote: post #37

Wouldn't (fully) burning all single-use plastics effectively make them no more long-lived and problematic than burning crude oil at sea? I know that's a low bar, but it seems like at least you're getting two uses out of them at that point...

And if you produce heat / energy from burning it, you can technically call it recycling :) Put some filters on top of the power plant exhausts and it's clean enough to build a ski slope on top of it.

The reference: https://en.m.wikipedia.org/wiki/Amager_Bakke

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

#76

Post by youcouldalwayz »

01HNNWZ0MV43FF wrote: post #40
whynotnowplz wrote: post #38

Why don't we throw all our trash into a volcano?

It's expensive to get the trucks there. Some toxic landfills like Florida don't even have any volcanoes: https://osm4wiki.toolforge.org/cgi-bin/wiki/wiki-osm.pl?proj...

I guess you can incinerate it and then use the byproduct to line the beaches since it might be cheaper than sand...

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

#77

Post by Certhas »

dwighttk wrote: post #53
piokoch wrote: post #50

There is no such a thing like "plastic". The article is about PET - polyethylene terephthalate, there are hundreds other "plastics", which different chemical propensities. The problem is not actual act of recycling, but figuring out what a given piece is made of. PET is popular - 70% of all bottles are made of it, but there are those 30%, so the most expensive part - sorting - has to be carried anyway. Plus we target…

There are actual reasons different plastics are used in different situations… it’s not just companies saying “ha ha this will be extremely difficult on the recyclers!” Some plastic needs to be heat resistant, some, it doesn’t matter. Some plastic needs to be easy to tear, some needs to resist tearing. Some plastic needs to be flexible, some needs to be stiff. Easily removable labels often fall off before they are act…

Of course there are always reasons. But as long as the costs of recycling are not borne by businesses doing the packaging, the business will always go with the 1 cent cheaper option, even if it makes recycling 100 times harder.

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

#78

Post by elzbardico »

piokoch wrote: post #50

There is no such a thing like "plastic". The article is about PET - polyethylene terephthalate, there are hundreds other "plastics", which different chemical propensities. The problem is not actual act of recycling, but figuring out what a given piece is made of. PET is popular - 70% of all bottles are made of it, but there are those 30%, so the most expensive part - sorting - has to be carried anyway. Plus we target…

Some times recycling, while possible, is not the best solution. Biodegradability makes a lot more sense in a lot of cases.

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

#79

Post by whywhywhywhy »

thrance wrote: post #51
Synaesthesia wrote: post #45

This is a realm where government regulations can really make a big difference. China banned single-use plastics. A lot of plastic use is really unnecessary.

And Trump reverted the ban on plastic straws. One step forward, three steps backwards...

Always seemed like greenwashing to care about the straw in the drink that’s on a plastic cup with a plastic lid from the beans shipped in a plastic bag and render the experience of trying to drink it as tedious as possible.

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

#80

Post by globnomulous »

unification_fan wrote: post #58
mbreese wrote: post #57

Earlier quoted context omitted.

This is actually one of the use cases the authors discuss in their paper. Sending mixed plastics through this process to extract the PET/PBT containing bits, and send the rest along their way.

The top comment could have been prevented had the OC read the article...

And as someone who is interested in the discussion and doesn't have time to read the article, I appreciate it.
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